E M M E T T A N D G R I N D L E Y O N C H E M I S T R Y OF F L E S H . 1 2 give decided increases on samples No. 5 and No. 13 and will recover potash in many cases where the official method loses it. I,ABORATORY A M E R I C A N AGRICULTURAL C H E M I C A L
CO.,
CARTERET, N. J.
CHEMISTRY OF FLESH. (SEVENTH PAPER.)
A PRELIMINARY STUDY OF THE EFFECT OF COLD STORAGE UPON BEEF AND POULTRY. (FIRST COMMUNICATION.) B y A. D . EMMETT A N D H. S. GRINDLEY. Received March 10, 1909.
U p to the present time, the modern method of cold storage must be considered as the best means of preserving flesh from the standpoint of supplying a product which closely resembles the freshly killed meats. Further, i t gives a safe and convenient medium wherein the physico-chemical changes of fresh meats can take place, as for example, rigor mortis which may occur almost immediately after death, later giving way to release rigor and thereby causing the flesh to become softer and more tender. Further in the continued hanging of the meats, they are supposed to become juicier, better in flavor and tenderer, or in the trade sense ripened and in prime condition for domestic use. Naturally, the influence of the factor of time of keeping meats in cold storage is an interesting one, especially if we consider the transportation of meat products both a t home and abroad. During a cold storage transit period of 2 2 days, the time required to go from Argentina to England, or of 40 days, the time to‘go from Australia to England, i t would be instructive and perhaps of economic value to know more of the chemical changes which take place in the stored meats during transit, Whether cold storage influences the nutritive value of the food stuff, appreciably affecting its palatability or its comestibility, and if so an approximation as to the time when the changes take place would add to our present knowledge. Another factor which is also of interest a t the present time is the effect of cold storage upon frozen fowl, whether the drawn or undrawn bird is preserved equally well for the same length of time, and what are the differences, if any, in nutritive value in the two cases as compared with fresh fowl.
With the object of making a chemical study of the influence of cold storage upon flesh, this investigation was undertaken. The present paper, which takes up the preliminary work in applying the improved methods of analyzing flesh,‘ to fresh arid refrigerated products, deals as nearly as possible with the existing conditions first, as they relate to the storage of chilled or refrigerated beef for periods of time which may be counted as comparable to those required to ship and transport our products to their destination, and second to the storage of drawn and undrawn frozen fowl. I n the meantime, W. D. Richardson2has applied the methods to a study of the deterioration and commercial preservation of flesh foods, and has proved that they are of real value in this connection. H. W. Wiley3 has also used our improved methods for the analysis of flesh in his study of the effects of cold storage upon poultry. HISTORICAL.
Among the investigators who have studied the effect of cold upon meats, may be mentioned Bouley4 who in 1874 presented a paper before the French Academy of Science. He stated, in using Tellier’s process of refrigeration, that a t a temperature between t-3’ C. and - 2 O C. meat would keep indefinitely as far as putrescibility was concerned b u t not so from the standpoint of an edible food, for while the tenderness of the meat was increased with the time of storage a peculiar fatty odor developed toward the end of the second month which affected the flavor. Pogziale and a little later, in 1889, a commission appointed by the French minister of war confirmed Bouley’s conclusions. In 1892, Grassmans found in making a study of beef, pork, and mutton: that flesh kept in cold storage for 8 months a t -2’ to -4’ C. did not deteriorate; that considered upon the dry basis the data indicated that there was no loss of nutritive material, this statement being based upon the following chemical determinations, moisture, total nitrogen, protein nitrogen by Stutzer’s method, and f a t ; that refrigerated meats cook by roasting and boiling in a shorter time than do the fresh 1
Grindley and Emmett, Journ. A m e r . Chem. Sac., xxvii. 658-678 Emmett and Grindley, I b i d . , xxviii, 25-63, (1906). Journ. Amer. Chem. S o c . , 3 0 , 1515-1564 (1908); THIS JOURNAL,
(1905). 2
H . S. Grindley, Journ. of the Amer. Chem. S o c . . xxvi, p . 1086 (1904); H . S. Grindley and A. D. Emmett, Ibid., xxvii, p . 658 (1905); A. D . Emmett and H . S. Grindley, I b i d . , xxviii, p , 25 (1905); P. F. Trowbridge and € I, S. Grindley. I b i d . . xxviii, p. 469 (1906); H . S. Grindley and H . S . Woods, Journ. o j B i d . Chem., 2 , p . 309 (1907); A. D . Emmett and H. S. Grindley, I b i d . . iii, p. 491 (1907).
4’3
1, 95-102. 3 “A Preliminary Study of the Effects of Cold Storage on Eggs, Quail, and Chickens,” U .S. Degartment of Agricullure, Bur. of Chem.,
Bu12. 115 4
(1908).
Comfit. rend., 79. Lamdw. Jahrb., 21.
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T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y . July, 1909
meats and that they are excellent in quality and tenderness; and that the loss of water by evaporation in storage was not a n appreciable one. He concluded by recommending cold storage as a means of keeping meats. I n 1897, A. Gautier' published the results of a detailed study upon the differences between fresh and stored frozen niutton and beef. His fresh meats were obtained from steers and sheep which had been raised in France, while his frozen meats were procured, frozen, and stored in Argentina. The method of preparing these cold storage products was to subject the carcass of the animal to -15' C., until frozen to the center and then to keep i t in a room at -5' C. I n this case, the meats were held in storage for 5 to 6 months. Gautier took for his chemical investigation samples from the shoulder cut for the mutton and from the rump steak cut for the beef. In all cases the visible fat and tendon were removed before making the analyses. The author made a d r y thorough examination, determining: moisture, fatty matter by ether, soluble matter by cold water and by hot water (using the residue from the fornier in the latter case), xnyosine, myostrom, peptones, extractive matter, glycogen, reducing substances, gelatin, and indigestible matter. We quote in part from his own summary: Meats frozen and thus preserved for 5 to 6 months a t -3' to -5' C. contain about I per cent. less of water than fresh butcher's meat. The assiniilable albuminoids are a little more increased in the frozen than in the fresh meats, being 1.25 per cent. greater for mutton and 0.39 per cent. for beef. Frozen meats contain less gelatin than fresh meats. The weight and composition of the fatty matter are the same in both cases, b u t in the frozen meat the fat takes on a slight characteristic taste which allows i t to be recognized after roasting. The extractive matters are not sensibly more abundant after storage, glycogen excepted. The peptonized parts of these meats have not appreciably varied. Boiled frozen meat is excellent and difficult to distinguish from fresh boiled meat. The cells of frozen meat remain unbroken on thawing, Frozen meats will remain untainted in the air for several days after being brought out of cold storage. By means of artificial digestion experiments with pepsin, there appears to be practically no difference in digestibility between fresh and frozen meats. 1 Rev.
d. hyg., 19.
I n 1901, C. Mail claimed that by proper cold storage treatment putrefactive changes could be prevented, but that the action of ferments or enzymes would still continue to some extent and either directly or indirectly cause the changes which take place in the so-called ripening of meats. Two years later, in 1903, M. Muller2 emphasized in a discussion upon the ripening of meat: that besides a temperature of oo C., the dryness of the air had a great deal to do in preventing the decay of such products. Under these conditions, the putrefying bacteria did not act, b u t the ferments or enzymes gradually made the meat more tender, juicy, and better in flavor. That the ripening of flesh which takes place throughout the entire mass and is not due in any sense to bacteria, is accompanied by a slow increase in acidity, while, on the other hand, decay of animal matter which is due to bacteria, produces an increase in alkalinity by the splitting off of ammonia. T h a t the odor of ripened meat which is often taken by the inexperienced as indicating putrescibility is an entirely distinct one. T h a t meats which have been ripened for roasting to the extent which the English fancy, will not do for boiling since they impart to the broth a disagreeable flavor. Finally, that broths from ripened meats are higher in extractives than those from fresh meats. In 1905, in a paper upon Ship Refrigeration read before the Cold Storage and Ice Association of Great Britain, maintained that chilled meats could be carried longer than 2 5 days, as was then cotisidered to be the limit for preservation. He added that at times meats from Australasia were on board as long as 40 days and yet when received were in perfectly satisfactory condition. It should be mentioned that Australasian chilled meats are slightly frozen and kept a t about ~ 9 . F., 5 ~ and hence they do not compare with our chilled meats which are not frozen and are held in cold storage a t approximately 33 O F. S.Ridea14 made a report, late in 1906, of a chcmical investigation which he had carried on for W. Weddels and Company of England. It contained data relating to the differences between Australian cold storage meats, both the chilled and frozen, and English and Welsh fresh meats. The beef, lamb, and mutton samples which he used were procured h'ahr. Gens., 4. Arch. f. Hyg., 47. 3 Cold Storage wnd Ice Trade Journal, Vol 15. No. 6. June, 1906. 1 Zert zc.
2
p . 22. 4
Cold Storage, England.
E M M E T T A N D G R I N D L E Y ON C H E M I S T R Y OF F L E S H in the open market, b u t a fairly good descriptive history of each was obtained. Of the imported Australian meats, the chilled beef was from a bullock 8 months old. It was kept in storage a t 29.5’ F. during the voyage of 31 days. The frozen beef was from a River Plate ox about three years old, and was held in storage a t 20’ F. during the transit of 31 days. No data were given as to how long these animals had been slaughtered before shipment. The leg cuts, “ Champion” brand, of frozen lamb and mutton, which were used, were held in storage two months and during shipping were kept a t about 20’ F. The domestic fresh beef was obtained from a Norfolk steer freshly slaughtered. The fresh lamb meat was of the Welsh-Raynor breed, and the mutton of the Leicester breed. I n making the comparative tests in studying the differences in nutritive value and digestibility of the fresh, chilled, and frozen meats, the author procured for the beef the shin cut and two pounds of steak, and for the lamb and mutton, the leg cut. The percentage of lean, bone, and excessive fat were determined. The lean of the beef shin was analyzed chemically for moisture, fat, and total nitrogen. Portions were also taken and boiled six hours with water and the resulting extracts, which the writer designated as beef tea, were analyzed for mineral matter, fat, total nitrogen, and total solids. The lean of the beefsteak was examined as to the ease of digestibility with pepsin and hydrochloric acid. I n the case of the leg of lamb and mutton, the meats were roasted in the usual manner, without removing the bone. The percentage loss in cooking and the amount of drippings were ascertained. The lean of the cooked meats was analyzed chemically for moisture, fat, and total nitrogen, and also as to differences in digestibility. The author, who had done some work in 1896 upon fresh and frozen domestic meats, concluded from this study, which confirmed the earlier one, that “ no incipient decomposition or hydrolysis takes place under cold storage,” and that the differences in nutritive value and digestibility of iresh, chilled, and frozen beef, lamb, and mutton were too slight to be of any economic importance. In this same year, following the agitation regarding the packing houses of United States, the question relating to the proper preservation of food products q y cold storage was brought before Congress. As a result, i t authorized that a “bacteriologicalchemical study of the effect of cold storage upon the
415
wholesomeness of food products” be made, and that special stress be put upon the chemical phase of the work. Among the first things to be taken up was the influence of cold storage upon flesh and in particular, the preservation of drawn and undrawn fowl. About this time H. S. Grindley made a report‘ to the Chicago City Council upon some work that had been done in this laboratory upon the differences between fresh and undrawn frozen fowl. The chemical data relating thereto are included in this paper. He stated that as far as could be found in the literature nothing had been done up to that time to prove scientifically: ‘‘First, that even slight decomposition takes place in the entrails of undrawn fowl during refrigeration ; second, that the contents of the entrails infiltrate, diffuse, or by osmosis pass into the flesh; third, that refrigerated poultry, drawn or undrawn, decomposes more readily or more quickly than does fresh poultry.” I n making some practical tests for this report upon undrawn fowl which had been held in cold storage for two seasons, from September 16, 1904, to October 16, 1906, i t was noted: that the general appearance of the undrawn refrigerated birds was not markedly different from the fresh birds; that the odor and appearance of the entrails were the same in both cases; that the refrigerated fowl, cooked by roasting and boiling, were exceedingly tender; that the roasted refrigerated fowl before adding any seasoning or condiments had a characteristic flavor which was not due to putrefaction but perhaps, as Muller2 states, to the ripening of meats; that the fresh and refrigerated fowl cooked by the ordinary household methods were eaten and relished by two families who did not know anything of their previous cold storage; that no injurious effects resulted in the eating of these meats, and that undrawn fowl after removal from cold storage kept as long in a n ordinary house refrigerator as did sound fresh chicken. Early in 1906, J. D. Bird,3 of Washington, D. C., made a practical test with drawn and undrawn turkeys. He hung the fowl, during the month of February, in the open air and found that a t the end of the first week the undrawn turkey was perfectly sound while the drawn one showed distinct signs of decay. E. M. Eckard, Commissioner of Health of Peoria, Illinois, made a bacteriological study of drawn and 1
Ice and Refrigeration, 31 (1906).
2 L O C . czt.
Ice and Refrigeration, 3 2 , 1 (1907).
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T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y . July, 1909
undrawn cold storage fowl. His results which were published’ in 1907 were based upon samples procured in the open market, and nothing was known concerning the condition of the chickens before they were placed in cold storage. His conclusions were very decidedly in favor of the drawn fowl as compared with the undrawn. Early in 1907, C. Harrington,2 Secretary of the Massachusetts State Board of Health, made a preliminary report to the state legislature upon an extended investigation of the question of the changes taking place by cold storing drawn and undrawn fowl. I n 1908, the final report3 of the investigation was made and presented by W. F. Boos under the title of the “Chemical Examination of Drawn and Undrawn Poultry Kept in Cold Storage.” The temperature of the storage room was maintained a t about oo F. Both chicken and duck were examined in the study. The problem resolved itself into the following questions: ( a ) Will the flesh of drawn or undrawn fowl undergo chemical change during cold storage? ( b ) Will drawn or undrawn fowl, after removal from cold storage, decompose with equal rapidity? (c) How will sterile drawn fowl compare with ordinary drawn and undrawn fowl as to their respective keeping qualities? The conclusions were : (u) That no chemical changes take place in cold storage in either drawn or undrawn poultry. This was determined by the fact that no ptomaines were found in using both Rrieger’s, and Baumann and von Udranszky’s methods, and by the fact that when extracts of the flesh, prepared by using alcohol, and then taking up the evaporated residue with water, were injected intravenousl-y into rabbits, no reaction was obtained. ( b ) That the undrawn fowl, when removed from coid storage, thawed in the open air, and kept a t 68’ F. for six days, showed less tendency to break down than did the drawn birds under exactly the same conditions. (c) That comparing the properly drawn, the ordinary drawn and the undrawn fowl when prepared fresh and left to hang a t 68’ F., the first showed the best keeping qualities, the second the next best, and the third the poorest. For the first 24 hours, the undrawn fowl kept equally as well as those properly drawn. (d) That the best means of preparing fowl for storage is to first draw them but properly, adding that ordinary drawing is wvrse by far than no drawing a t all.” “
Chicago Clinic, 20, 1 . New York Produce Review and American Creamery 23--25 (1907). a Thirty-ninth Annual Report of the State Board of Health of Massachusetts. 1
2
H. A. Higley,‘ of the Brooklyn Diagnosis and Research Laboratory, prepared a detailed report as to the differences between fresh and refrigerated, drawn and undrawn fowl. Basing his conclusions upon established bacteriological facts, he found that the edible portions of healthy, dead, undrawn poultry and game do not contain any bacteria, toxines, or ptomaines that are harmful when eaten by man so long as such poultry is kept free from putrefaction; that poultry that goes into cold storage in good bacterial condition comes out in exactly the same condition that i t went in, so long as the temperature of the poultry is kept low enough (joC., or below) to prevent the growth of putrefactive bacteria, and finally that the longer poultry remains frozen, the less bacteria does i t contain.” I n January, 1908,Wiley and associates2 made a preliminary report upon an investigation which was being carried out a t Washington, on the effect of cold storage upon eggs, quail and chickens. The bulletin5 giving the detailed results of this work, was issued in November. I n the case of t h e eggs, a bacteriological, microscopical and chemical examination was made. The first showed that a t the end of three months, the whites and yolks were still separate but at the end of six months, they were more or less intermixed, the limiting membrane having been dissolved by the bacteria. The microscopical study indicated that a t the end of 3%- and 6-month periods, the eggs were not unlike the fresh, but that a t the end of 12% months, the yolks of the cold storage product were flattened and contained rosette crystals. The chemical examination showed: That the cold storage eggs lost, during a period of one year, IO per cent. of their weight, due chiefly to water; that the amount of coagulable protein and the lecithin phosphorus in samples, which were boiled, was less; that the proteose and peptone nitrogen increased, and that the amido constituents decreased. I n taking up the study of fowl, the work was divided somewhat : First, a preliminary investigation with quail and chicken, under known conditions as to cold storage, was undertaken in which organoleptic tests and bacteriological examinations were made, and second, a comparison of market cold storage chicken was undertaken upon a histological, bacteriological and chemical basis. I n the former, drawn and undrawn birds were used. From the organoleptic tests, there seemed to be no ‘ I
1
The Natwnal Provisioner. 38, 13.
2
Science, 27, p. 295 (1908).
3
U.S. Depariment Agr., Bur. C h n . ,Bull. 110.
E M M E T T A N D GRINDLEY ON C H E M I S T R Y OF FLESH.
417
marked distinctive points between the two. Com- of the cell, might produce abrasion of the cell wall paring them with fresh samples, there was no depending, as Gautier' also stated, upon the rapidity apparent difference at the end of six weeks; how- of the freezing and the subsequent thawing, and ever, after a period of three months or longer, the that the solidifying point does not occur at any stored fowl showed a perceptible difference in the specific temperature but that it depends upon the uncooked condition and in some cases in the cooked. soluble solids. From the bacteriological examinaThe bacteriological examination gave positive evi- tion, it was found that in the freezing the bacteria dence of bacterial growth during the storage period. became surrounded by solid barriers of ice through The reduced temperature retarded their growth, which they could not penetrate and hence they but it did not destroy the organisms-a fact which would cease to grow. In the chemical study, a comparison of the composition of the frozen sample Penningtonl also found in the case of milk. I n the study of the market cold storage chickens, was made with that of the fresh meat. There the samples were compared with fresh fowl. The appeared to be no general tendency for the amprevious history of the birds was not known. I n moniacal, the coagulable or the albumose nitrogen the chemical work, the light and dark meats were to increase or decrease and hence chemically the each analyzed. A special study was made of the products of bacterial growth, if there were any, fat, the usual determinations being followed out. were inappreciable. The authors concluded from For the lean meat, the method, as published from their results that frozen meats can be kept in cold this laboratory,2 was used with some modifications. storage under proper conditions for a period of The conclusions, which were of a tentative nature, 554 days or perhaps longer. were: (a) The histological examination of the I n a second paper,2 Richardson and Scherubel muscle of the stored and unstored fowl showed have made a study of the preservation of meats distinct and progressive changes in the structure stored at temperatures of 2 to 4' C., that is, above of the fibre. ( b ) The bacteriological study gave the freezing point. The same chemical methods evidence of the presence of an appreciable number were used here as in the preceding two studies; of bacteria in the edible stored flesh but none in however, the data for the phosphorus and sulphur the fresh samples. ( c ) The cheniical analysis in- are not reported. Tests were made to ascertain dicated only slight variations for the different whether the chemical methods would detect any nitrogenous constituents but marked ones for the changes resulting from known bacterial decomposifat. tion of meat. I n the first experiment, samples of At the same time that Wiley and associates chopped beef knuckle were prepared, and to the made their preliminary report, Richardson read same, I cc. of a putrefying meat infusion was added. a papers on "The Criteria of the Deterioration of These tests were kept for definite periods of time Flesh Foods." He used, in general, the methods a t room temperature. It was found that the of this laboratory with further improvements. total nitrogen, the meat base nitrogen, the coaguSpecial emphasis was laid upon the value of the lable nitrogen, the albumose nitrogen, the ammoniadetermination of ammoniacal nitrogen. Later cal nitrogen, and the total solids all increased up Richardson and Scherube14 published an elaborate to and including the ninth day. The total nitrogen investigation upon experiments with samples of and the meat base nitrogen showed a general infrozen beef knuckle kept a t -9 to -12' C. His- crease throughout, while the albumose and coagutological, bacteriological, and chemical studies lable nitrogen increased regularly a t first, but later were made. In the chemical work, the authors began to decrease, yet always remaining higher than reported, in addition to the determinations made a t the start. The total acidity determinations in our study, those for the ammoniacal nitrogen, were of no definite value. I n the second test, acidity and sulphur. The histological data showed : chopped meat was again used and in some cases That the physical changes in frozen meats were preservatives were added. The samples were kept due either to the evaporation of the water, or to in Mason jars a t z to 4 O C. The authors state that the pressure produced by expansion in the freezing these experiments were not very satisfactory but, of the water; that the formed ice which was outside in general, they seemed to show that the added 1 Journ B z o l . Chem., 4 , 3 5 3 (1908) preservatives assisted in arresting the bacterial Loc czt a Sclence. 2 7 , 6 8 7 (1908) Journ Amer Chem S o ' , 3 0 . 1515 (1908). 2
'
1LOC.
cit.
THISJOURNAL, I, p . 9 5 (1909).
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i
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y .
action. The low temperature, however, was the chief agent. In a third test, cuts of beef knuckle were used. They were held in cold storage at 2 to 4O C. for varying lengths of time. It was found on the 31st day, and thereafter the samples were covered with a slimy layer. The analysis of the entire cut then showed the ammoniacal nitrogen to be twice as high as in the case of the sample for the seventh, fourteenth, and twenty-first days, and i t also showed the albumose nitrogen to be about 30 per cent. higher. Analyses of samples on the thirty-ninth, forty-sixth, and fifty-third days were about the same as those for the thirty-first day. On and after the sixty-fifth day, there was a marked increase in the total, the coagulable, the albumose, and the ammoniacal nitrogens and in the total solids. In a fourth test, pieces of knuckle which had begun to decompose on keeping a t 2 to 4 O C. were transferred on the fifty-fourth day to a room whose temperature was -9 to -12O C. It was found that the reduced temperature arrested the bacterial decomposition. From the above historical review, it is evident: first, that up to within the last two and a half years, comparatively little has been done outside of Gautier's work in making a n extensive chemical study of the differences between fresh and cold storage flesh; second, that in all the cases reported, excepting those of Wiley, Richardson and Scherubel, and Grinclley, either the conditions as to the teniperature of the cooling room and the methods of preparing the meats for storage did not correspond with those in common usage in United States at present, or else, in the most comparable cases the chemical constituents determined and reported were quite few; third, that the tests in these cases, again excepting Wiley, Richardson and Scherubel, and Grindley, were made on the one hand, with chilled or frozen meats and on the other, with those used either soon after slaughtering or after hanging in the air for 30 to 60 hours at a temperature of approximately 9' C. and not in the strict sense of the word with meats which had been properly cold stored immediately after killing and then examined at different periods of time; fourth, that practically nothing has been reported, outside of Grindley's work, in making a chemical study in comparing the composition and nutritive value of fresh fowl with drawn and undrawn frozen fowl; and finally, that no one, as far as could be discerned, has published any results where the fresh, refrigerated, or frozen meats were all procured from the same
July, 1909
animal, the same breed of animals, or from animals reared in the same locality, and hence as far as our present knowledge shows us, i t might be assumed that the differences reported could have been still less, more, or perhaps of a different nature, and therefore, it can be stated that the actual influence of cold storage upon the chemical composition of flesh has not been accurately and properly determined. It was therefore thought to be of interest, as has previously been stated, to make a preliminary chemical study along the lines just suggested and thus to get a working basis for a more extensive and elaborate investigation upon the chemistry of cold storage flesh products. EXPERIMENTAL.
The method of refrigerating beef in this country is to rapidly chill the carcass as soon as slaughtered in order to remove the animal heat and thus to prepare i t for the cooling chamber. It is then transferred to a well-ventilated room where the air is properly dried and kept in circulation. The temperature of the room is generally about 34' F., but in cases of long storage i t may be almost freezing. The meat is not allowed to freeze. I n the case of fowl, the most satisfactory method is to gradually freeze them solid as soon as killed, either drawn or undrawn, and then to keep them in cold storage a t IO' F. Technically speaking, the former procedure of preparing flesh for storage gives the chilled or refrigerated meats, and the latter method the frozen meats. I n the present study, three experiments are reported: two upon beef and one upon fowl. Two of the experiments upon beef relate to the uncooked meat held in storage for different periods of time. In the first, the analyses of eight wholesale cuts are given and in the second, the analyses of four wholesale cuts. The third experiment, which is upon uncooked fowl, consists of the analyses of one lot of fresh unstored chicken, two lots of drawn frozen chicken, and two lots of undrawn frozen chicken. Experiment No. I.-In this experiment which was made in December, 1905, a registered Hereford steer, 18 months old, and fed for the market by the Station in connection with a n extensive feeding experiment, was slaughtered by a private cold storage company. The above-described niethod of preparing the animal for cold storage was followed as closely as possible. The two halves of the
E M M E T T A N D G R I N D L E Y ON C H E M I S T R Y OF F L E S H . carcass, after being chilled, were placed in cooling rooms a t 33-35O F. After two days the left half was removed from cold storage and cut up by a n experienced cutter. All the wholesale cuts, the analysis of only four being reported here, were freed from excessive visible f a t , tendon and all bone. The portions of the resulting lean beef were each thoroughly sampled by grinding them in a chopper. The right half of the carcass was held in storage for 22 days or practically three weeks longer than the left half. I n this case, the wholesale cuts, the round, rib, plate, and full loin were freed from excessive visible fat, tendon, and all bone. The lean meats were then sampled in the same manner as those obtained from the left half and analyzed. From the several data, we have, on the one hand, to compare the composition of the lean of the round, rib, plate, and full loin cuts held in cold storage for two days with the corresponding wholesale cuts of the right half of the same animal held in cold storage for 22 days. In the former case, the laboratory numbers are 1924, 1927,1929,and 1926 respectively, and in the latter case, they are 1954, 1957, 1959,and 1956 respectively. Experiment No. 2.-A well fed, registered Durham steer about one year old was used in this experiment. He was slaughtered in January, 1906,and prepared for cold storage in the manner described in Experiment I. The two halves of the carcass were kept in cold storage 6 days when they were hoth removed and the square chuck and full loin cuts were taken from each. Those from the right half were immediately returned to cold storage and held there for 37 days more or practically five weeks a t a temperature of 33 to 35' F. The cuts from the left half were immediately sampled as in the previous experiment and analyzed. The cuts from the right half were also prepared for analysis in this manner. The laboratory numbers for these samples are for left chuck and loin 1993 and 1988, and for the right corresponding cuts 1973 and 1969, respectively. The data obtained in these two experiments are assumed to be more comparable, when calculated to the same basis, than if the samples for examination had been taken from neighboring cuts of onehalf or from corresponding cuts of different animals which had not necessarily been raised in the same locality. I t can hardly be doubted that the lean of the corresponding cuts of the right and left half of the same animal are essentially the same chemi-
419
cally, while data herein reported show that the same wholesale cuts from the same half of different animals are not necessarily alike. Experimeizt Nu. 3.-In this experiment, cold storage frozen drawn poultry are compared with undrawn fowl similarly prepared and kept, and further, fresh unstored poultry are compared with drawn and undrawn frozen fowl. The first lot, laboratory No. 2057, was undrawn, frozen, and held in storage for 21 months. The second lot, laboratory No. 2 1 1 0 , was drawn, frozen, and held in storage for an unknown period. The third lot, laboratory No. 2 1 1 1 , was undrawn, frozen and held in storage 4 months. The fourth lot, laboratory No. 2 1 1 2 , was drawn, frozen, and kept in storage 4 months. The fifth lot, laboratory No. 2067, was unstored and fresh. Lots three, four, and five were procured and prepared a t the same time. In all cases the fowl when selected appeared perfectly sound. Nothing was known as to the strain, or kind of poultry, or as to their feed or the methods of preparing them for the market. The third, fourth and fifth lots of poultry were killed, dressed, and packed by a large wholesale firm in Chicago, under the direction and continuous supervision of one of us. The same day that the poultry were killed and dressed, they were placed in one of the best cold storage warehouses in Chicago and immediately frozen. The storage poultry was maintained a t a temperature of 10' F. The fact should here be noted that this supply of poultry used in our investigation was immediately placed in cold storage after it was killed and dressed. The dressed poultry was not allowed to stand nor was it shipped from outlying districts before being stored. In preparing the samples for analysis, several chickens were taken from each lot and thus a fair representative of the lots was obtained. The skin and any large lumps of fat were removed. After removal of the bone, the flesh thus obtained ineach case was ground in the chopper, and then sampled and analyzed. CHEMICAL METHODS USED.
In making the chemical study of the cold storage samples of flesh for these experiments, the methods used in the chemical analysis were essentially the ones as previously published from this laboratory. Briefly stated the custoniary method of analyzing flesh was modified so as not only to aid in adding Grindley and Emmett, J o u m . Amer. Chem. SOC..27, 658-678 Emmett and Grindley, Ibid., 28, 25-63 (1906).
(1905).
420
T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y . July, 1909
much more to our limited specific knowledge of the subject but to give a systematic and applicable means of ascertaining these data. The ordinary method as used by all experiment stations, consisted mainly in determining, in the air-dried samples, the total nitrogen, total ash, fat, and moisture. The first improvement lay in the fact that it was found that fresh flesh could be so sampled that it could be analyzed directly without previously air-drying it. Naturally, this gave a ready and more rapid means of determining the above four constituents. Further, it did away with the questionable changes that take place in the air-drying of the sample such as the coagulation and cleavage of some of the proteins and the possible loss of nitrogen, volatile fatty acids, etc. The second step was the adoption of the method of extracting the fresh sample with cold, neutral, distilled water. By this means, a distinct differentiation was made in separating out several of the important constituents of flesh. Among the constituents so separated are : first, those substances which are most easily digested and of service in the nutritional economy as the albumins, some of the globulins, the proteoses, and any protamins; second, those substances which are thought to contribute in part to the flavor of cooked meats and to aid in stimulating the action of the gastric glands, as the nitrogenous extractives, of which creatin and the purin bases in some complex combination are members; third, those substances which aid in furnishing heat and energy to the body as the non-nitrogenous extractives, glycogen and para-lactic acid, the latter being also considered by some to play a part in the ripening of meats; and fourth, those substances which aid in maintaining the osmotic pressure of the body liquids, assist in carrying on the normal functions of irritabilitv of muscle and nerve, and add flavor or increase the palatability of the cooked meats as sodium chloride, potassium chloride, potassium phosphates, and doubtless some calcium salts. The next improvement in the method was the estimation of the different forms of phosphorus and more especially the soluble phosphorus according to a modification of H a r t and Andrews' method' of separating the inorganic and organic forms in seeds and seedlings. By this means the total soluble, the soluble inorganic, the soluble organic, the insoluble and the total phosphorus were estimated. The data thus obtained upon phosphorus 1. Am. Chem. I., 8 0 , 4 7 0 (1903).
were found to give an insight into the differences in the flesh from animals of different ages, in the different cuts of meat, in cooked meats, and in broths. I n applying this method of analysis to the cold storage flesh, the following determinations are reported : ( a ) Water-soluble matter, including the coagulable, the non-coagulable, the protein, the non-protein, and total nitrogen ; the coagulable, the non-coagulable. and total protein; the nitrogenous, non-nitrogenous, and total organic extractives ; the ash; and the inorganic, organic, and total phosphorus. ( b ) Water-insoluble matter, including the total nitrogen; the protein; the f a t ; the ash; and the phosphorus. (c) Total matter, including the water; the dry substance; the protein; the nitrogen; the phosphorus; the ash; and the fat. I t should be added in connection with the chemical analysis, that a t the time of making this preliminary study upon cold storage flesh, the methods of determining creatin,' ammonia,2 and total acidity were not sufficiently developed for use. DISCUSSION.
I n the following discussion, first, the d a t a for the refrigerated uncooked beef will be taken up, this including Experiment I , where the halves of beef were held in cold storage for two days and three weeks, and also Experiment 2 , where the chuck and loin wholesale cuts of the right and left halves were kept in storage for periods of 6 and 43 days; second, the drawn and undrawn frozen fowl will be studied; third, the drawn and undrawn frozen fowl will be compared with the fresh fowl; and fourth the differences in the cases of refrigerated uncooked beef and the frozen fowl will be contrasted. THE INFLUENCE OF COLD STORAGE UPON LNCOOKEL) REEF.
Fresh S d s t a n c e . I n the two experiments which relate to uncooked beef, the data from the analysis of the lean of the twelve wholesale cuts are reported in Table I , as calculated in per cent. of the fresh substance. I t will subsequently be seen that these several d a t a thus presented are not comparable from the standpoint in question. I n the above paragraphs it was stated that in preparing the samples of beef for analysis, the excessive visible f a t was first removed and the resulting lean meats were then taken for the chemical study. 1 Grindley and Woods, J . Biol. Chem., 1,309 (1907). Grindley, I b i d . , 3,491 (1907). 2 Gill and Grindley, Science, 27, 497 (1908).
Emmett and
E M M E T T A N D G R I N D L E Y O N C H E M I S T R Y OF FLESH.
.
In the removal of the excessive fat in the trimming of the cuts, i t was naturally quite impossible to make a quantitative separation from the lean and no attempt was made to do so. A glance at the data in Table I, Experiment I , will show that in a number of instances the amount of fat remaining in the samples analyzed was more in some of the 2-day samples, while in others, i t was less than in the 22-day samples. For example, in the plate cuts (1929 and 1959) the percentages of fat are 19.56 and 21.53 respectively, and in the loin cuts (1926 and 1956) they are 12.66 and 1 1 . 9 9 respectively. Such differences in the data, calculated to the fresh suhstance, influence in a reverse manner the percentages of the other constituents as is shown in this case where the data in Table I, Experiment I , indicate that the round cut (1954), the rib cut (1957), and the plate cut (1959) lost, during the storage of 20 days, from i to 1.7 per cent. of water, while the loin cut (1956) showed no
42 1
change. Similarly, the d a t a of Experiment 2 , show that the chuck cut (1993) gained during the cold storage period of 37 days I per cent. of water and the loin cut (1988) lost 0.6 per cent., all of which is quite contradictory to the general expectation and belief. Further, attention should be called to the fact that if the d a t a from the analysis of the lean beef were calculated to the original fat content of the wholesale cut, the resulting figures would show similar variations to those above for the corresponding cuts. In Table I, the total percentages of fat and water calculated to the wholesale cut without bone are given in brackets to illustrate this fact. In the rib cuts (1927 and 1957), the percentages of fat are 36.02 and 35.55 respectively which are nearly the same, while in the loin cut (1926) i t is 34.76 per cent. and in the corresponding cut (1956), i t is 30.79-a difference of 4 per cent. It is evident from the above statements, that the
TABLEI.-CHEMICALCOMPOSITIONOF COLD STORAGE FLESH.
EXPERIMENT LEAN OF WHOLESALE CUTS OF BEEF,UNCOOKED. Description oi sample..
...............
..................... .......
Laboratory N o . . Time held iu cold storage (days)
Water: I n fresh substance.. In original wholesale c u t . . D r y substance: Soluble.. Insoluble.. Total Protein: Soluble coagulable.. Soluble non-coagulable.. Total Insoluble. Total Organic extractives: Nitrogenous Non-nitrogenous. Total Fat (by ether): In fresh substance.. I n original wholesale cut. Ash : Soluble Insoluble.. Total Nitrogen: As soluble coagulable protein. As soluble non-coagulable protein.. Total As soluble non-protein substance.. Total. Insoluble.. Total... Phosphorus: Soluble inorganic. Soluble organic.. Total Insoluble.. Total
(Calculated to the Fresh Substance.) Lean beef, Lean beef, rib. round. 1954 22 P . Ct.
1927 2 P. ct.
1957 22 P. Ct.
1929 2 P. ct.
1959 22 P. Ct.
1926 2 P.ct.
1956 22 P. ct.
70.19 (61.98)
65.92 (49.08)
64.45 (49.28)
61.66 (40.69)
59.98 (42.72)
67.26 (50.02)
67.27 (52.84)
5.77 22.67
5.72 24.11
4.77 29.70
4.85 31.17
4.25 34.22
3.81 36.06
5.57 27.96
5.33 27.61
28.44
29.83
34.47
36.02
38.47
39.87
33 * 53
32.94
2.29 0.15
2.04 0.25
1.77 0.18
1.88 0.26
1.45 0.17
2.06 0.21
1.90 0.20
2.27
2.IZ
15.26
15.52
1924 2 P. ct.
.......... (61.75)
................
........... ............................ ........................
...........................
....... ... ........................... ...
.......................... ........................ ........................ .................. ................... ........................... ........................ ...........................
Lean beef, loin, 7 -
................71.29
.......................... ........................ ........................... ................ ............ ........................... ......................... ........................... ....................... ................... ...........................
Lean beef, plate.
2.44
2.29
I .95
2.I4
1.62
16.18
15.85
15.10
15.12
14.55
1.37 0.20 I .57 14.33
18.62
18.14
17.05
17.26
16.17
15.90
17.53
17.64
1.24 1 .22
1.14 1.37
0.99 1.06
0.89 1.09
0.88 1.01
0.74 0.95
1.07 1.29
2.46
2.51
2.05
1.98
1.89
1.69
1.15 1.35 2.50
2.36
6.32 (18.73)
8.20 (17.84)
14.46 (36.02)
15.90 (35.55)
19.56 (46 56)
21.53 (43.99)
12.66 (34.76)
11.99 (30.79)
0.87 0.17
0.92 0.06
0.73 0.15
0.74 0.11
0.55 0.20
0.80 0.04
1.04
0.98
0.77 0.14 0.91
0.88
0:85
0.75
0.84
0.85 0.10 0.95
0.366 0.024
0.326 0.040
0.284 0.028
0.300 0.043
0.233 0.026
0.219 0.031
0.329 0.034
0.304 0.035
0.390
0.366
0.312
0.343
0.259
0.250
0.363
0.339
0.396
0.366
0.317
0.286
0.282
0.237
0.368
0.342
0.786
0.732
0.629
0.629
0.541
0.487
0.731
0.681
2.588
2.537
2.416
2.418
2.328
2.294
2.442
2.483
3.374
3.269
3.045
3.047
2.869
2.781
3.173
3.16.1
0.098 0.050
0.118 0.052
0.097 0.042
0,105
0.043
0.078 0.052
0.096 0.029
0.096 0.045
0.110 0.044
0.148
0.170
0 . I39
0.148
0 .I30
0.125
0.141
0.154
0.082
0.055
0.055
0.046
0.053
0.072
0.061
0.230
0.225
0.194
0.I94
0.183
0.044 0.169
0.213
0.215
422
T H E J O U R N A L OF INDU.STRIAIa A N D ENGINEERING C H E M I S T R Y . July, 1909 TABLEI.-CHEMICAL COMPOSITION OF COLD STORAGEFLESH-(Comt&zued). EXPERIMENT LEAN OF WHOLESALE CUTS OF BEEF.UNCOOKED. (Calculated to the Fresh Substance.) Description of sample . . . Lean beef, Lean beef, chuck. loin.
. . .. . . . . .
.
. .. . . . . . . . . . . . . . . .
Laboratory N o . . . Time held in cold storage (days) . ..
7
1973 6
P.ct. Water: 70.71 I n fresh substance.. . . ,, (60.77) In original wholesale cut. Dry substance: 4.81 Soluble. . , , 24.37 Insoluble. Total 29.22 Protein: 1.68 Solublc coagulable.. 0.26 Soluble non-coagulable. . ,, Total 1.94 15.66 Insoluble.. , Total 17.60 Organic extractives: Nitrogenous 0.89 Non-nitrogenous.. . 1.24 Total.. . . , , 2.13 Fat (by ether). In fresh substance. . . , 8.51 In original wholesale cut. , (20.98) Ash: Soluble. . . . 0.78 Insoluble.. 0.20 Total 0.98 Nitrogen: As soluble coagulable protein.. 0.268 As soluble non-coagulableprotein.. 0.042 Total 0.310 As soluble non-protein substance.. 0.285 Total 0.595 Insoluble. . . . 2.506 Total 3.101 Phosphorus: Soluble inorganic.. . , . 0.097 Soluble organic. , 0.047 Totcl 0.144 Insoluble.. . . . , . 0.069 Total.. .. 0.213
. ......
.. . . . . .. . . . . . . .. ... . . .. ... . . . . . . . . . . . . . . . . . . . . . .. . . . I
........................ .. . . . . . . . . . . . . .. . . . . ........................ . . . . . . . . . . . . . . . . . . .. ........................ .................... . . .. . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . .. . . . . . . . .... . .. . . .. . . . . . . .. . . . . . . . . . ... . . . . . .. . . . . . . . . . . . ........................ .. .
........................
........................ . . .. . . . . . . . . . . . . . .. .................... ... . . .. . . . . . . . . . .. . . . . . . . . . . . . . ........................ .. ... . . . . . . . . . . . . .. .... .. .. . ... .. . . . .
d a t a of the lean of the beef of the wholesale cuts, when calculated as in Table I, upon the fresh basis, cannot be compared directly as to the chemical changes which may have taken place during cold storage, and i t is also evident that if this data were calculated back to the original fat content, they would still not be strictly comparable for the same reasons, Therefore, in order to remove both the small and large errors and put the data upon a fair basis for comparison, all the results for the experiments were calculated to the fat-free basis as shownjn Table 11.
Fresh Substance, CalczLlated to the Fat-free Basis. Chemical composition of cold storage uncooked beef, calculated tb the fat-free basis: I n considering the results of Experiments I and 2 , where the difference in time of storage of the several corresponding cuts was 20 days in the former case
-
1993 43 P. ct.
-
1969 6 P.ct.
1988 43 P. ct.
71.69 (61.03)
71.12 (56.27)
70.50 (54.18)
5.56 23.26
5.52 23.18
28.82
28.70
6.43 23.88 30.31
2.05 0.22
2.03 0.18
2.27
2.2I
16.34
15.69
2.13 0.28 2.41 15.93
18.61
17.00
18.34
1.02 1.55
1.02 1.44
2.57
2.46
1 .26 1.89 3.15
6.69 (19.67)
7.35 (26.02)
7.76 (28.77)
0.72 0.23
0.85 0.14
0.87 0.17
0.95
0.99
1.v4
0.328 0.035
0.325 0.029
0.340 0.045
0.363
0 ‘354
0.385
0.325
0.329
0.405
0.688
0.683
0,790
2.614
2.510
2.549
3.302
3.195
3.339
0.125 0.018
0.134 0.064
0.085
0.101 0 .os5 0 .I57 0.083
0.228
0.240
0.215
0.I43
0.198 0.017
and 37 days in the latter, i t will be seen, as regards the general opinion that meats lose water during cold storage, that of the 22-day samples only one shows any apparent decrease. It should be noted in this connection that the air of the storage room in which these meats were kept was moist, thus preventing to a considerable extent desiccation. The percentages of water in the round, plate, and loin cuts are practically the same, while in the rib cut (I9j7), i t is 0.51 per cent. lower than in the corresponding cut (1927). The averages of these four respective samples are 76.47 per cent. for the 2-day period and 76.3%per cent. for the 22-day period, showing a difference of only 0 . 0 9 per cent. On the other hand, the chuck and loin cuts in Experiment 2 show that during the 37-day period there was a distinct loss of water, there being a decrease of 0.94 per cent. for the former (1993) and 1.13 per cent. for the latter ( 1 9 8 8 ) ~with an average difference of 1 . 0 4 per cent, This distinct loss of moisture
E M M E T T A N D G R I N D L E Y ON C H E M I S T R Y OF F L E S H . in Experiment 2 may be explained in three ways: first, as due to the additional time during which the meats were held in cold storage; second, to the fact that these wholesale cuts (1993 and 1988) were cut from the right half a t the same time that the corresponding ones (1973 and 1961) were cut from the left half, and hence the difference in the size of the pieces might possibly allow of a more extensive drying out during the subsequent period of cold storage than in the case of Experiment I where the entire halves were allowed to hang; and third, to the fact that the air of the storage room was not as moist as it was in the case of Experiment I . Muller,l however, claims that the size of the cut bears no relation to the percentage of loss of water during the period of hanging in cold storage. In Experiment I , the soluble dry substance tends to increase slightly during storage in the round cut (1954) and in the rib cut (1957), the
423
maximum amount being in the latter 0 . 1 8 per cent., which is 3.2 per cent. of the total soluble dry substance. The plate (1959) and loin (1956) cuts show a decrease of from 0.41 to 0.28 per cent. respectively, or 7 . 7 to 4.4 per cent. of their total amounts. The averages in all four cases are 5.83 per cent. for the 2-day samples and 5 . 7 1 per cent. for the 22-day samples which indicates very little difference due to storage. The data in Experiment 2 are noticeably higher in soluble dry substance in the samples held in storage for a longer time. In the chuck cut (1973) the percentage of water-soluble dry substance is 5.30, while in the corresponding cut (1993) which was stored 37 days longer, it is 5.92, or 1 1 . 7 per cent. gain. In the loin cuts (1969 and 1988) the respective percentages of soluble dry substance are 5.97 and 6.91, showing a gain of 15.75 per cent. The average of the two cuts indicates a difference in the constituents of 0.78 per cent. which is equal
TABLE~ ~ . - - ~ H E M X C A LCOMPOSITION OF
COLD
STORAGE FLESH.
EXPEKIMENT LEAN OF WHOLESALE CUTSOF BEEP,UNCOOKED. (Calculated to the Fat-free Basis.) Lean beef, Lean beef, Lean’beef, plate. round rib.
Description of sample.. .... Laboratory N o . . .................. Time held in cold storage (days).
... Water. ...........................
Dry Substance: Soluble. ..... Insoluble.. , Total.. Protein: Soluble coagulable. . . . . . . . . . . . . . . Soluble non-coagulable.
. ...
.........
Total. ....................... Organic extractives: Nitrogenous.. Non-nitrogenous. . Total.. ...................... Ash: Soluble. ........................
...
......................
Total.. Nitrogen: As soluble coagulable protein..
.........
...
Total. As soluble non-protein substance Total. Insoluble. Total.. Ratio of non-protein to protein: In water extract.. In meats.. Phosphorus: Soluble inorganic.. Soluble organic.. ................ Total. Insoluble. Total
....................... ...................... ......................
.
...............
..................... .............. ....................... ...................... ........................
1 LOG.
cir.
Lean beef, loin.
76.58
1926 2 P.ct. 76.32
1956 22 P.ct. 76.25
Average of (4). 2 P.Ct. 76.47
5.27 18.20
4.86 18.56
6.32 17.36
6.01 17.71
17.70
5.71 17.92
23.80
23.47
23.42
23.68
23.75
23.53
23.63
2.21 0.32
1 .80 0.21
1.75 0.25
2.34 0.24
2.15 0.25
2.16 0.21
c _ -
1924
76.32
1954 22 P.ct. 76.44
1927 2 P.ct. 76.71
76.20
1929 2 P.ct. 76.53
6.18 17.50
6.23 17.32
5.55 17.74
5.73 18.07
23.68
23.55
23.29
2.23 0.27
2.06 0.21
2
P.ct.
2.45 0.16
1957 22
P.Ct.
1959 22
P.c t .
S ,113
Average of (4). 22 P.Ct. 76.38
2.61
2.50
2.27
2.53
2.01
2.00
2.58
2.40
2.37
17.32
17.26
17.57
17.90
18.06
18.31
17.32
17.60
17.57
2.09 0.27 2 .36 17.79
19.93
19.76
19.84
20.43
20.07
20.31
I9.90
20.00
19.94
20.13
1.32 1.31
1 .24 1.49
1.15 1.23
1 .05 1.29
1.09 1.25
0.95 1.21
1.30 1.53
1.21 1.46
1.21 1.33
1.11 1.36
2.63
2.73
2.38
2.34
2.34
2.16
3.83
2.67
2
54
2.47
0.93 0.18
1 .oo 0.06
0.90 0.16
0.86 0.18
0.92 0.14
0.70 0.26
0.91 0.04
0.97 0.11
0.91 0.13
0.88 0.15
I.II
I .06
1.06
1.04
1.06
0.96
0.95
1.08
I .04
1.03
0.392 0.026
0.355 0.044
0.330 0.033
0.355 0.051
0.289 0.032
0.280 0.040
0.373 0.039
0.344 0.040
0.346 0.032
0.334 0.043
0.08
0,399
0.363
0.406
0.321
o ,320
0.412
0.384
0.378
0.377
0.423
0.399
0.369
0.338
0.350
0.302
0.417
0.388
0.390
0.357
0.744
0.671
0.622
0.829
0.772
0.768
0,734
2.889
2.929
2.771
2.814
2.811
2.841
3.551
3.600
3.586
3.579
3.575
1: 1.06 1: 0.99 1: 10.74 1: 7.63
1: 0.99
1: 0.97 1: 8.18
1: 1.06 1: 9.01
0.050
0.106 0.054
0.125 0.048
0.841
0.798
0,732
2.771
2.812
3.612
2.762 3.560
3.544
3.605
3.560
1: 0.98 1: 7.52
1: 1 .oo 1: 7.92
1: 0.98 1: 8.60
I: 1.20 I: 9.67
1: 0.92 1: 9.17
0.104 0.053
0.128 0.056
0.113 0.049
0.124 0.051
0.097 0.064
2.861
0.123 0.037
0 . I57
0.184
0.162
0.I75
0.161
0.160
0.088
0.060
0.064
0.054
0.066
0.056
0.109 0.051 0.160 0.082
0,245
0-244
0.226
0 ,229
0.227
0.216
0.242
1: 8.24 0.125 0.I75
0.160
0 . I73
0.069
0.244
0.075 0.235
0.060 0,233
424
T H E J O U R N A L OF I N D U S T R I A L A N D ENGI&VEERING C H E M I S T R Y . July, 1909 TABLEII.-cHEMICAL
COMPOSITION OF COLD STORAGE FLESH.--(CO&W~~).
EXPERIMENT 2.-LEAN
Description of sample..
. . . .. . . . . . , , . . . .
. ...
. . .. . . . . . . . ..
Lahoratory N o . . , . , . Time held in cold storage (days) ...
.. . . . Water. . . . . . . . . . . . . . . . . . . . . . . . . , . . . . . D r y Substance: Soluble. . .. . . . . . . . .. . . . . . ... . . . . . . . Insoluhle.. . . . .. . . . .. . . . . . . .. .. . . . . Total ........................... Protein: Soluble coagulable. . . . . . . .. . .. . . . . . . Soluble non-coagulable. . . . . . . .. . . . . . Total ...,....................... Insoluble. . . . . . , . . ... . . . ..... . . . . ..
...........................
Total Organic extractives: Nitrogenous. , , Non-nitrogenous . Total Ash : Soluble.. . . . . , , Insoluble. . Total Nitrogen: As soluble coagulable protein. As soluble non-coagulable protein.. Total As soluble aon-protein substance.. Total.. , Insoluble..,. Total Ratio of non-protein to protein: I n water extract.. In m e a t s . . . . . . . . . . . . . . . . . . . . . . . . . . Phosphorus: Soluble inorganic.. . Soluble organic.. Total Insoluble. . Tot al...........................
. . . . . . . . . . .... . . . . . . . . .. . . . . . . . . . . . . . . . . ........................... . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . .
...........................
. . . . ... .. ....................... . .. .. . . . . . . . . ..... . . . . . ... . . . . . . . . . . .. . . . . . . . . . . . . . .
.................. ......... ... . ... . . . . ..... . .
.. . . . . . . . ... . . . . . .. .. . . . . . . . .. . . . . ........................... . . . . . . . .. . . . . . . . ...... . .
OF
WHOLESALE CUTS OF BEEP, UNCOOKED.
(Calculated to the Fat-free Basis.) Lean beef. Lean beef, chuck. loiti.
----
Average of (2).
Average of (2).
6 P. ct.
P. ct.
77.13
76.09
5.63 17.23
6.41 17.49
24.22
22.87
23.90
2.29 0.30
2.02 0.23
2.24 0.26
1973 6
1993 43
1969 6
1988 43
P. ct.
P. ct.
P. ct.
P. ct.
77.35
76.41
76.91
75.78
5.30 17.35
5.92 17.67
5.97 17.12
6.91 17.31
22.65
23.59
23.09
1.84 0.28
2.18 0.23
2.20 0.19
a
43
2.12
2.4
2.39
2.59
2.25
2.50
17.13
17.43
16.97
17.12
17.27
19.25
19.84
19.36
19.71
17.05 19.30
79.77
0.98 1.35
1.09 1.65
1.10 1.56
1.35 2.03
1.04 1.45
1.22 1.84
2.33
2.74
2.66
3.38
2.49
3.06
0.85 0.22
0.92 0.15
0.94 0.19
0.89 0.18
0.85 0.22
1.07
0.77 0.24 I .OI
I .07
I.13
r .07
1.07
0.293 0.046
0.350 0.037
0.351 0.032
0.366 0.048
0.322 0.039
0.358 0.042
0.339
0487
0.383
0.414
0.361
0.400
0.312
0.346
0.356
0.435
0.334
0.391
0.651
0 * 733
0,739
0.849
0.695
0.791
‘2.741
2.786
2.714
2.740
2.727
2.727
3.392
3 -519
3.453
3.589
3.422
3.554
1: 1.09 1: 9 . 8 7
1: 1 . 1 2 1: 9 . 1 7
1: 1.07 1: 8 . 4 4
1: 1 . 9 5 1: 7 . 2 4
1: 1 . 0 8 1: 9 . 1 1
1: 1.02 1: 8 . 0 9
0.106 0.051
0.133 0.019
0.109 0.061
0.144 0.069
0.107 0.056
0.139 0.044
0-157 0.076 0.233
0 . I52
0.170
0.213
0.163
0.183
0.091
0.090
0.018
0.083
0 .OS4
0.243
0.260
0.231
0.246
0.237
to 13.9 per cent. of the total amount. This gain is sufficient to show that in Experiment 2 there is a distinct difference from Experiment I in the water-soluble dry substance. The percentages of insoluble dry substance in the samples of beef of the first experiment are inclined to be a little high in the meats which were refrigerated for 2 2 days. This difference is due chiefly to a corresponding increase in the insoluble protein. The one exception to this statement is in the round cut (1954) which is 0.18 per cent. lower in insoluble dry substance and 0.06 per cent. in insoluble protein. The other cuts, the rib (1957), the plate (1959) and the loin (1956) are each about 0.35 per cent. higher, showing a n average for the four 2-day samples of 17.70 per cent. and for the 22-day samples of 17.92 per cent., which is equivalent to a gain of only 1.2 per cent. The chuck and loin cuts in Experiment 2 are a little higher in insoluble dry substance for the samples held in storage for 43 days, being in
the former case 0.32 per cent. and in the latter o.zg per cent. with a n average increase of 0.26 per cent., or a percentage gain of 1.5. Compared in this respect, there is very little difference in the insoluble dry substance between the meats held in storage for the 2- and 22-day periods and those 1for 6- and 43-day periods. Concerning the total dry substance, it can be stated that, with the exception of the rib cut (1957), the d a t a for the 2 2 day samples are almost identical to those for the 2-day samples. The rib cut shows a gain of 0.51 per cent., due in the main to the loss of water. The average of the respective four cuts are 23.53 and 23.63 per cent, The data for the second experiment, however, show a n increase of 0.94 per cent. for the chuck cut (1993) and of 1.13 per cent. for the loin cut (1988), making an average gain of 1.03 per cent. in total dry substance which is 4.5 per cent. of the total. A comparison of the above various forms of dry substance indicates from the data in the two
E M M E T T A N D G R I N D L E Y ON C H E M I S T R Y OF F L E S H . experiments that the meats held in storage for 43 days made a distinct gain over those held for 2 2 days in the soluble form, a slight one in the insoluble form and a distinct one in the total. Regarding the different forms of protein in these experiments, practically nothing can be stated of the coagulable form. The differences in this form in the first experiment are slight and variable, averaging 2.16 and 2.09 per cent. of the coagulable protein present for the 2- and m-day samples, while in the second experiment, the 37-day samples show a tendency to gain, being for the chuck cut (1993), an increase of 0.34 per cent. and for the loin cllt (1988), an increase of only 0.09 per cent. The non-coagulable protein which includes any peptones that may be present, in the first test increases throughout the four samples, but in two of the cases, the loin and the plate cuts, the gains, 0.01 and 0.04 per cent., are so small that they may be considered within the limits of the errors of the method. The other two cases (1954 and r957), the round and rib cuts respectively, are decidedly *higher, being in the former 0 . 2 7 per cent. against 0.16 per cent. and in the latter 0.32 per cent. against 0 . 2 1 per cent. However, the total gain in these two cases is not of an amount to be of any value in indicating decomposition of the flesh by supposing the gain to be due solely to peptones; especially is this true if we take into consideration the averages of the 2 - and 22-day samples which are 0 . 2 1 and 0 . 2 7 per cent. respectively. These same statements apply to Experiment 2 where the comparative period of cold storage is 37 days. In the chuck cut (1993) there is a decrease, 0.05 per cent. of the non-coagulable protein and in the loin cut (1988) an increase of 0.11 per cent. on 0.19 per cent. The fact that these differences in the 37-day period are no greater than in the 20-day period tends to further confirm the statement that the increase in the non-coagulable protein is not due to bacterial decomposition. The influence of cold storage upon the total soluble protein is very slight in Experiment I . Here, the differences are variable, being noticeably high in but one case. This is in the 22-day rib cut (I957), where there is an increase of 0.26 per cent. The averages of total soluble protein for the corresponding 3- and =-day cuts are 2.37 and 2.36 per cent. respectively. The data for experiment 2 show a slight gain in the total soluble protein for both of the cuts, being 0.29 and 0 . 2 0 per cent. respectively for the 37-day samples of the chuck
425
and loin cuts, making an average increase of 0.24 per cent., which is 10.6 per cent. of the total soluble protein. -4s stated, in considering the insoluble dry substance, the differences there were due, in the main, t o similar differences in the insoluble protein. The increase in the insoluble protein is greater in the 37-day samples than in the 22-day samples, being on the average 0 . 2 2 per cent. in the first instance and 0 . 2 2 per cent. in the last one, which means a percentage gain of 1.3 and 1.2 respectively. The total protein in the two experiments is variahle, in the first one, where the most distinct differences are in samples 1957 and 1959 which show the former to have 0.59 and the latter 0.24 per cent. more of the constituents than the corresponding 2-day samples. The other differences are no greater than those that might occur in duplicate analyses. The averages show a very slight gain: the 2-day stored meats have 19.94 per cent. of total protein and the 22-day meats 20.13 per cent. The samples of the second experiment have an increase in the total percentage of protein of 0.59 for the 43-day refrigerated chuck sample (1993) and one of 0.35 for the similar loin sample (1988). The averages of the two cuts are 19.30 per cent. for the 6-day refrigerated meats and 19.77 for those refrigerated 43 days, making a difference of 0.47 per cent. as against 0.19 per cent. in the 2z-day samples, or a percentage gain of 2.4 in the former and 0.96 in the latter. From this discussion upon the differences in the amounts of protein in the meats held in storage for periods of 2 2 and 43 days, the data indicate that the coagulable protein tends to be a trifle higher in the latter case, the non-coagulable to be about the same in both instances, the total soluble to be slightly higher in the second experiment and the insoluble and total protein to be somewhat higher in the 43-day tests. These differences in the data appear to be due mainly to the greater loss of water, but this point will be' considered later. Of the organic extractives in Experiment I , the nitrogenous form, which is thought by some to contribute, a t least in part, to the flavor of meat, shows, contrary to expectations, if this assumption be correct, a decrease throughout for the 22-day samples of about 0.10 per cent., or 8.2 per cent. of the total nitrogenous organic extractives present. On the other hand, in the refrigerated test for 43day samples of meat, there is an increase in both cases, being in the chuck cut (1993) 0.I I per cent.
426
T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y .
and in the loin cut (1988) 0 . 2 5 per cent., averaging 0.18per cent. or 17.3 per cent. of the total amount. It is also significant to note in Experiment I , the apparent constancy of the non-nitrogenous organic extractives, which, upon the theory that the ripening of meat is due to an increase in the sarcolactic acid, i t would be expected to show an increase. In the second experiment, for the 37-day interval, these data for the non-nitrogenous extractives indicate a consistent gain for the 43-day samples, being 0.30 per cent. in the chuck cut, and 0.49 per cent. in the loin cut, averaging 0.39 per cent. against 0.03 per cent. in the 22-day samples of Experiment I , or a percentage gain of 26.9 per cent. in the former case. The per cent. of total extractives is about the same in the corresponding 2- and 22-day samples. The slight differences are variable, being in some cases greater and in others less. The averages of the four cuts are for the fornier period 2.54 per cent., and for the latter period 2.47 per cent. For the second test, the percentage of total extractives is higher in the 43-day chuck and loin samples (1993 and 1988), being for the chuck 0.41 per cent. and for the loin 0.72 per cent., with an average increase for the two cuts of 0.57 per cent., which actually means a percentage increase of 22.9. This comparison of the data for the extractives tends to show that the saniples of meat held in cold storage for 2 2 days did not approach the degree of ripeness, which would be indicated chemically by an increase in the different organic extractives, that the 43-day samples did, and hence the latter meats should be theoretically the more highly flavored and pleasing when cooked. A study of the data relating to the forms of ash in both experiments shows nothing definite. The differences in nearly all cases are very slight. They are variable and not at all consistent and hence will not be considered in detail. As regards the different kinds of nitrogen, those for the coagulable, the non-coagulable, and the total soluble protein, and the insoluble have been considered indirectly under the corresponding headings of the protein, since these latter were obtained by multiplying each of the former by 6.25. The non-protein nitrogen in Experiments I and 2 shows more distinctly the decrease in the 22-day samples and the increase in the 43-day samples than does the non-protein form proper, being about 8.5 per cent. for the former and 17.1 for the latter. In the case of the total soluble nitrogen, it will be
July, 1909
seen that in Experiment I , the 22-day samples are all, with the exception of the rib cut sample (1g57), distinctly lower. Here the slight gain is due in part to the difference in water content and in part to the gain of protein nitrogen. The average for all the tests shows a difference in the soluble matter of 0.034 per cent. which is a decrease of 4.3 per cent. of the total. This lower percentage of nitrogen is accounted for in part by the decrease in the non-protein nitrogen and in part by the possible formation of acid albumen as a result of the effect of the increase of the soluble inorganic phosphate, and this explains further the increase in the coagulable nitrogen and insoluble nitrogen. I n Experiment 2 , the consistent gains of total soluble nitrogen in the 43-day samples are explained as due to similar gains in both the soluble protein and non-protein nitrogen. The averages for the 6- and 43-day samples are 0.695 per cent. for the former and 0.791 per cent. for the latter, making a difference of 0.096 per cent. which is equal to a gain of 13.8 per cent. The total nitrogen in Experiment I , is quite variable in the first two I samples, the round cuts (I924 and 1954) and the rib cuts (1927 and 1957). In the first case, there is a loss for the 22-day sample of 0.052 per cent. out of a total of 3.612 per cent., while in the second case there is a gain of 0.061 per cent. on a total of 3.544 per cent. The other two samples, the plate and loin cuts, are slightly lower than those held in storage for a longer period. The average per cent. of the total nitrogen for the two sets is for the 2-day samples 3.579 and for the 2z-day samples 3.575, which is very close. Likewise, in considering this form of nitrogen, the total in the second experiment, there is a noticeable gain in both the chuck and loin cuts, which were kept in cold storage for 43 days, against those kept for 6 days, being for the first samples 3.392 and 3.519 per cent., and for the second samples 3.453 and 3.589 per cent., making an average per cent. of 3.422 for the 6-day and 3.554 for the 43-day period, which is 0.132 per cent. or a percentage gain of 3.8. Further, i t will be of interest in the consideration of the forms of nitrogen to note the influence of the above-mentioned variances upon the ratio of the non-protein to the total soluble protein, and to the total protein nitrogen. In but one instance, in the two experiments, is there any marked difference in the ratios of the non-protein nitrogen to the soluble protein. This variation is in the case of the 2 - and 22-day samples of the rib cut, experi-
E M M E T T A N D G R I N D L E Y O N C H E M I S T R Y OF F L E S H . ment I (1927 and 1957), but i t is not sufficient to modify the statement that these ratios remain nearly constant throughout the two tests showing that the changes which took place in the non-protein nitrogen were either slight or that they occurred in almost a similar proportion to those in the soluble protein nitrogen. Regarding the ratios of the soluble non-protein nitrogen to the total protein nitrogen, that is, the soluble and insoluble forms combined, the data in Experiment I show an appreciable increase in each of the 22-day samples, averaging for all I : 9.01 against I : 8.18 in the a-day samples. This is due to the fact that the non-protein nitrogen in the 22-day sample is 8.5 per cent. lower and the insoluble protein nitrogen a trifle higher, 1.1 per cent., throughout this series. In the case of Experiment 2 , the reverse condition seems to be true. The ratios of the non-protein to the total protein nitrogen are lower in both of the 43-day samples as compared with the 6-day samples. The averaged calculated ratios are I : 8.09 in the former case and I : 9.1I in the latter. This is explained in part, that like the above instance the insoluble protein nitrogen is higher, 1.7 per cent., in the samples which were held in cold storage for the longer period, but unlike it, these samples were also higher in the non-protein and soluble protein nitrogen, having a gain of 17.0 and 10.8 per cent. respectively. However, while this increase of the protein nitrogen is considerably greater than that in Experiment I , the gain in the non-protein nitrogen is still greater and as a result the ratios in the 43-day samples are lower than in the 6-day samples. Of the various forms of phosphorus, the watersoluble inorganic shows, perhaps, the most consistent and appreciable differences. I n Experiment I the data for the inorganic phosphorus show a distinct increase in the 22-day samples, being- a gain in every case of from 0.011 per cent. in the rib cut to 0.026 per cent. in the plate cut. The averages for all four cuts are in the 2-day samples 0.106 per cent. of phosphorus and on the 22-day samples 0.125 per cent., making a percentage gain of about 17.9. I n Experiment 2 the inorganic phosphorus shows the same tendency to be higher in the samples held in cold storage for the longer period, 43 days. Here, the average for the two cuts are 0.107 per cent. for the 6-day samples and 0.139 per cent. for the others. This means an increase of phosphorus in the latter case of 29.9 per cent. The soluble organic and total soluble phos-
427
phorus in the corresponding samples of Experiments I and 2 show no consistent variations throughout. The general tendency of the total soluble forms in the meats held in cold storage for the longer time is to be either practically the same or a little higher than that in the samples kept for the short periods. I n both experiments, the percentage averages are higher in the 2 2 - and 43-day meats, being in Experiment I , 0.160 and 0.173 and in Experiment 2 , 0.163 and 0.183 respectively for the short and long periods. The insoluble phosphorus in Experiment I shows a tendency to be lower in every case in the 22-day samples, being on the average O . O I j per cent., or calculated in per cent. of the total a decrease of 2 0 . 0 per cent. In Experiment 2 this form of phosphorus is higher in the 43-day samples for the chuck (1993), but on the other hand it is decidedly lower for the loin cut (1988), so much so that the result must be considered as questionable. Regarding the total phosphorus, it will be seen in the first experiment that there is practically no difference in the amounts in the 2 - and 22-day samples. The average in the former case is 0.235 per cent. and in the latter 0.233 per cent. I n the second experiment, however, little can be said since, as just cited, the determination in the 43-day loin sample (1988) of the insoluble phosphorus which is gotten by subtracting the total soluble from the total phosphorus, seems to be unreliable, apparently due to the low per cent. of total phosphorus. From the foregoing consideration of the different forms of phosphorus, the data show: First, pretty conclusively that the percentage of the watersoluble inorganic phosphorus is higher in the meats which have been kept in cold storage for the longer periods and that the averages in these cases seem to indicate on the whole that the longer the time of storage, the greater is the tendency of the inorganic phosphorus to increase. This gain in inorganic phosphorus does not show any apparent definite source. I n some cases, i t seems to be derived from the organic forms, in others, from the insoluble form, and again in others from both of them. It is significant to note in this connection, since the data in Experiment I show so slight an increase in the non-nitrogenous organic extractives which includes lactic acid, that the first stage in the acidity and the ripening of meat is due rather to the increase of the inorganic phosphates. This fact tends to confirm the conjectures of several physiologists. Second, the data show that the
42 8
T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y . July, 1909
percentage of total soluble phosphorus of the meats kept in cold storage for the longer periods is slightly higher. Third, the data indicate that in Experiment I the amount of insoluble phosphorus is lower in the 22-day samples, and, fourth, that the percentage of total phosphorus in these same meats is practically identical with those in the a-day samples. From the above detailed discussion of the data in Experiments I and 2 , calculated to the fat-free basis, the following general summary can be made: First, as regards the eight samples in Experiment I , which were kept in cold storage a t about 33' F. for 2 and 2 2 days respectively, the average results of the chemical study show that very few changes took place in the latter samples during the 20-day interim. There was practically no loss of water and total nitrogen and no appreciable gain in watersoluble dry substance, soluble protein, non-nitrogenous organic extractives, and total phosphorus. There was a n apparent slight tendency of an increase in the insoluble dry substance, the coagulable protein, the insoluble protein, the total protein, and the total soluble phosphorus. And, finally, the only consistent changes of real note were the decrease of 8.5 per cent. in the non-protein nitrogen and accordingly in the nitrogenous organic extractives, and also a slight decrease in the total soluble nitrogen and an increase of 17.9 per cent. in the soluble inorganic phosphorus. These statements show conclusively that as far as these data are concerned, the meats which were held in cold storage for practically three weeks were just as nutritious as were those which had been kept for only two days. Further, they indicate that the intra-chemical changes were exceedingly few and that there was nothing as far as the increase in proteose and peptones were concerned, to prove any kind of decomposition to have occurred during this time. Second, as regards the four samples in Experiment 2 , the data here reported show that when the meats were kept in cold storage for 43 days or three weeks longer than those in Experiment I , the proportional distribution of the several constituents in the samples which were held for the entire period, in the former case underwent more changes than those which were held in storage for 2 2 days, as in the first experiment. Here, the results show that an appreciable loss of moisture took place during the six weeks, being on an average 1.04 per cent. or 1.3 per cent. of the total. Natur-
ally, this decrease in the water content effected the percentages of total dry substance in a reverse manner, increasing it 1.04 per cent. or making a total percentage gain, on this assumption, of 4.6 per cent. This total gain is distributed between the soluble ,and insoluble forms of dry substance, being in the former case 3.4 and in the latter 1.1 per cent. of the total or in per cent. of their respective total amounts 13.8 and 1.5 per cent. However, these proportional gains in the soluble and insoluble dry substances, and therefore in many of the constituents, are not necessarily alone due to the loss of water b u t are, as will be seen in a subsequent discussion, in part effected by other influences during the cold storage period. The data for the other chemical constituents reported show consistent gains in both the chuck and loin cuts, being for the soluble, insoluble, and total protein 11.1, 12.9, and.2.4 per cent. respectively of the total amounts in each case; for the nitrogenous, non-nitrogenous, and total organic extractives, respectively 17.3, 26.9, and 22.9 per cent. of the amount in the 6-day samples; for the coagulable nitrogen 1 0 . 2 per cent., the total soluble, the insoluble, and total protein nitrogen 10.8, 1.3, and 2.4 per cent. respectively; the non-protein nitrogen 16.6 per cent. and the total soluble, insoluble, and total nitrogen 13.8, 1.3, and 3.9 per cent. ; and finally for the inorganic and total soluble phosphorus 29.9 and 12.3 per cent. respectively. From these statements regarding the d a t a herein reported of Experiment 2 , Table 11, calculated to the fat-free basis, it must be concluded when comparing the meats which were kept in cold storage for 43 days with similar ones kept in storage for 6 days, that during the 37-day interval the former became somewhat drier, higher in the soluble, and total protein nutrients, also higher in the different organic extractives and in soluble phosphates, while the non-coagulable protein which includes any peptones, showed no greater change than in the former experiment. These facts all indicate, chemically, that these meats, during the cold storage period, had retained their full nutritive value.
Fat-Free Substance Calculated to the S a m e W a t e r Content. Chemical Composition of Cold Storage Uncooked Beef, Calculated to the Same Water Content. -In considering further the data in Table 11, calculated to the fat-free basis, i t will be recalled that
EMiWETT A N D G R I N D L E Y ON C H E M I S T R Y O F F L E S H . the differences in the chemical composition of the meats, which were kept in storage for varying lengths of time, were much greater in the second experiment than in the first one, and since there was a noticeable loss of water in the former case, and almost none in the latter, i t might be assumed that these variances were due primarily and solely to the drying out of the meat, a fact which is claimed by some investigators. In order to ascertain an idea of the exact state of affairs in this connection, the data in Table I1 were calculated so as to represent as nearly as possible the chemical changes, other than the loss of moisture, which took place during the storage. By so doing, the data should represent, in comparing i t with that just discussed, whether the changes in the percentage of the constituents during cold storage were due to loss of water only, and consequently something regarding the actual intra-chemical rearrangement due to the so-called ripening of meats. With these objects in view, the data as
presented in Table I1 were so calculated that the analysis of the corresponding cuts, which were kept in cold storage for the entire period, are upon the same moisture basis as those kept for the shorter time. Table I11 shows the results in this form. I t will be seen from the data that the only noticeable differences produced by the recalculation of the results in Experiment I , are in the case of the rib cuts, 1 9 2 7 and 1957,but even here the changes are very slight and do not modify the conclusions previously made relating to the changes which took place in storage during the first 3 weeks. This close agreement was to be expected. Since the samples in this test lost almost no moisture during the 20-day period of storage, the subsequent corrections would be very slight and inappreciable. On the other hand, in Experiment 2 , the data as given in Table I11 are quite different in several respects from those in Table 11. In both cases, the chuck and loin cuts, there is, as formerly, a distinct gain of soluble dry substance, but i t is
TABLEIII.-CHEMICALCOMPOSIT~OW OF COLDSTORAGE FLRSH, FAT-FREE SUBSTANCE. EXPERIMENT LEAN OF WHOLESALE CUTS OF BEEF.UNCOOKED. (Calculated to the Same Water Content.) Description of sample . . . . . . . . . . . . . . Lean beef, Lean beef, Lean beef, Lean beef, round. rib. loin. plate.
..................
Laboratory N o . . Time held in cold storage (days) ....
Water. ........................... Dry substance: Soluble. Insoluble. Total ........................ Protein: Soluble coagulable. Soluble non-coagulable. Total Insoluble. Total.. Organic extractives: Nitrogenous .................... Non-nitrogenous ................. Total ........................ Ash: Soluble. Insoluble. ...................... Total ........................ Nitrogen : As soluble coagulable protein.. A s soluble non-coagulable protein.. Total ........................ As soluble non-protein substance.. Total ........................ Insoluble. ...................... Total ........................ Ratio of non Drotein to Drotein: In water extract.. . . . . . . . . . . . . . . . . In meats.. ..................... Phosphorus: Soluble inorganic.. .............. Soluble organic. ................. Total ........................ Insoluble.. Total
........................ ......................
.............. .......... ........................ ...................... ......................
........................
...
..................... ........................
----
7
1924 2
1954 22
1927 2
1957 22
P. ct.
P . ct.
P. rt.
P. ct.
76.32
76.32
76.71
6.18 17 .50
6.26 17.41
23.68 2.45 0.16
2.61
329
---
76.71
1929 2 P. C t . 76.53
5.55 17.74
5.61 17.68
23.67
23.20
233.29
2.24 0.27
2.06 0.21
2.16 0.31
Average of (4).
Average of (4).
1959 22
1926 2
1Y56 22
2
22
P. ct.
P . ct.
P . ct.
P.
Ct.
P. ct.
76.53
76.32
76.32
76.49
76.49
5.27 18.20
4.87 18.60
6.32 17.36
5.98 17.66
5.83 17.70
5.69 17.84
23.47
23.47
23.68
23.64
23,53
23.53
1.80 0.21
1.75 0.25
2.34 0.24
2.14 0.25
2.16 0.21
2.07 0.27
2.51
2.27
2.47
2.01
2.00
2.58
2.39
2.37
17.32
17.35
17.57
17.52
18.06
18.35
17.32
17.55
17.57
17.70
19.93
19.86
19.84
19.99
20.07
20 ,.35
19.90
19.94
19.94
20.04
1.32 1.31
1 .25 1.50
1.I5 1 .23
1.03 1.26
1.09 1.25
0.9.5 1.21
1.30 1.53
1 .19 1.44
1.21 1.33
1.11 1.35
2.63
2.75
2.38
2.29
2.34
2.16
2.83
2.63
2.54
2.46
0.93 0.18
1 .oo
0.06
0.90 0.16
0.92 0.14
0.70 0.26
0.91 0.04
0.96 0.11
0.91 0.13
I.II
1.06
1.06
0.84 0.18 I .02
1.06
0.96
0.95
1.07
1.04
0.88 0.15 I .03
0.392 0.026
0.357 n ,044
0.330 0.033
0.347 0.050
0.281 0.040
0.373 0.039
0.343 0.040
0.346 0.032
0.332 0.043
0.418
0.401
0.363
0.397
0.321
0.412
0.383
0.378
0.375
0.423
0.401
0.369
0.331
0.289 0.032 o .321 0.350
0.303
0.417
0.387
0.356
0.841
0.802
0,732
0.728
0.671
0.624
0.829
3.560
2.34
2.771
2.776
2.812
2.800
2.889
2.935
2.771
2.806
0.390 0.768 2.811
3.612
3.578
3.544
3.528
3.560
3.559
3.600
3.576
3.579
1: 0 . 9 8 1 : 7.52
1: 1 .oo
1: 0 . 9 8 1: 8 . 6 0
1: 1.20 1: 9.67
1: 0.92 1: 9.17
1: 0 . 9 9 1: 7.63
1: 0 . 9 9 1 : s 24
1: 0.97
1: 7.92
0.104 0.053
0.129 0.056
0.113 0.049
0.121 0.050
0.097 0.064
0.109 0.051
0.125 0.050
0.106
0.157
0.185
0.162
0.171
0.161
0.160
0.160
0.088
0.175
0.054 0.160
0.060
0.064
0.053
0.066
0.056
0.082
0.069
0.075
0.061
0.245
0.245
0.226
0.224
0,227
0.216
0.242
0,244
0.235
0 .23.3
1: 1.06
1: 10.74 0.123 0.037
0,770
1:8.18
0.731 2.829
1: 1.06 1: 9 . 0 1 0.124 0.048
0.172
430
T H E JOURNAL OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y .
July, 1909
TABLEIII.-CHEMICALCOMPOS~TION OF COLDSTORAGE FLESH,PAT-FREES ~ ~ s ~ ~ ~ c ~ - ( C o n i i n u e d ) . EXPERlMRNT 2 . - b A N OF WHOLESALE CUTS O F REEF, UNCOOKED. (Calculated to the Same Water Content.) Description of sample.. . Lean beef, Lean beef, chuck. loin. Average Average 7 c Laboratory No.. , 1973 1993 1969 1988 of (2). of (2). Time held in cold storage (days). . . 6 43 6 43 43 6 P. ct. P. ct. P. ct. P. ct. P. Ct. P. Ct. Water. . . , . , 77.35 77.35 76.91 76.91 77.13 77.13 Drv substance: . , Soluble. . 5.30 5.68 5.97 6.59 5.63 6.13 Insoluble. , 17.35 16.97 17.12 16 . 5 0 17.23 16.74 Total 22.65 22.87 22.65 93.09 22.87 23.09 Protein: 1.84 Soluble coagulable. , ,, , 2.09 2.20 2.18 2.02 2.13 Soluble non-coagulahle. . . 0 28 0.22 0.19 0.29 0.23 0.26 Total 2.12 2.25 2.31 2.39 2.47 2.39 Insoluble. . 17.13 16.74 16.97 16.52 17.05 16.53 Total 18.92 19.25 19.05 19.36 18.79 19.30 Organic extractives: 0.98 Nitrogenous....................... 1 .05 1.10 1.29 1.04 1.17 Non-nitrogenous.. . .. . . , 1.35 1.58 1.56 1.45 1.93 1.75 Total 2.33 2.63 2 .g2 2.66 3 22 2.49 Ash: 0.85 0.74 0 92 Soluble. . 0.90 0.89 0.82 0.22 0.23 Insoluble. 0.15 0.18 0.20 0.18 Total I .08 0.97 1.07 I .07 1.02 1.07 Nitrogen: 0.293 0.336 0.351 As soluble coagulable protein. 0.349 0.322 0.342 0.046 As soluble non-coagulable protein.. 0.036 0.032 0.039 0.041 0.046 Total o ,361 0.339 0.372 0.383 0.395 o ,383 0.312 0.332 As soluble non-protein substance.. , . 0.356 0.414 0.334 0.373 Total 0.756 0.651 0.704 3.739 0.809 0.695 2.741 2.675 Insoluble. 2.714 2.612 2.727 2.644 Total 3.422 3.392 3.379 3.453 3.421 3.400 Ratio of non-protein to protein: 1: 1 . 0 9 1: 1 . 1 2 1: 1 . 0 7 1: 0 . 9 5 1: 1 . 0 8 1: 1 . 0 2 I n water extract.. 1: 9 . 8 7 1: 9 . 1 7 1: 8 . 4 4 1: 7 . 2 4 1: 9 . 1 1 1: 8.09 I n meats. , . Phosphorus: 0.106 0.128 0.109 0.107 0.137 0.132 Soluble inorganic.. 0.051 0.018 0.056 0.042 0.061 0.066 Soluble organic.. . 0.170 0.203 Total 0.163 0.157 0.146 0.174 0.082 0.076 0.087 0.090 0.017 0.052 Insoluble. . 0,226 Total 0.260 0.220 0,233 0,233 0.245
... . . . . . . ... . .
... . . . . . . . . . . . .. . . . . . . .. . . . . . . . . . . . .. . . . . . . . . . . . . .. . . . . .. .. . .. . . . . . . . . . . . . .. . . . . . . .. . . . . . .... . . . .
...........................
. . . . . . .. .... . . . . . .. .... . ........................... . . . ... .... . ... .. . . . . . . . . ........................... . . . . . .. . . . .
...........................
.
. . . . . . . . . . . . ... . .. . . . . .. .. . . .. . . ... . .. ... . . . . .... . .
........................... . . ... . . .. . ........................... . ........................... .... .. .. . .. . . . . .. . . . . . . . . ........................... .. . . .. .. . .. . . . . . . . ..... . ... . . . .. . .. . . . . . . . .. ... . .. . . . . .. . . . . .. . ... . . . . . . . . . . ........................... . .. .... . . ... . . . . . . . . . . . . ...........................
less, being, in per cent. of the totals in the 6-day samples, 8.9 per cent. against 13.8 per cent. The percentage of insoluble dry substance in Table I11 is less in the 43-day samples, whereas it was higher in Table 11, being 0.49 per cent. in the former case and 0.26 in the second, which means a total loss of 2.8 per cent. on the one hand and a total gain of 1.5 on the other. Perhaps, the most important changes are in the proteins: the coagulable form shows nothing consistent, being higher in the chuck cut and lower in the loin c u t ; the non-coagulable is practically the same as in the former case; the total soluble and insoluble forms of protein show only a slight tendency to gain, while the total form is lower, whereas it was higher in Table 11. As regards this last point, the average percentage loss of the insoluble and total protein are 3.0 and z .o respectively, whereas the average percentage loss and gain were 1.3 and 2.4 respectively in Table 11. The percentages of the organic extractives still show the same general tendency to gain during
the longer period of hanging in cold storage as in Table 11, b u t to a lesser degree. The percentages of the nitrogenous forms represent a total gain of 12.5 per cent. now; while it was 17.3 per cent., the non-nitrogenous shows a n increase of 20.7 per cent. against one of 26.9 per cent., and the total extractives a gain of 17.3 per cent. in Table I11 and of 22.9 per cent. in Table 11. The total soluble nitrogen indicates a n actual gain due to the hanging in cold storage of 8.8 per cent. against one of 13.9 per cent. when the loss of water was not taken into account. The insoluble nitrogen shows a loss of 3.0 per cent. under these conditions while i t indicated a gain of 1.3 per cent. before. The total nitrogen in the q3-day samples was formerly 3.9 per cent. higher than that in the 6-day samples but now it is practically the same in both cases, being lower by 0.6 per cent. of the total amount for the 43-day meats. Concerning the soluble inorganic phosphorus, the data are higher in the meats kept in storage for the whole period, but like the organic
E M M E T T A N D GRINDLEY ON C H E M I S T R Y OF FLESH. extractives the percentage gain is lower, being on the average 23.3, allowing for the loss of water, and 29.9, not taking this factor into account. I t is thus apparent that many of the changes which took place in the meats of Experiment 2 during cold storage were due to other causes than simply the loss of moisture. I n the discussion, it has been evident that the loss of water produced a proportional increase in all the other constituents of the meats, but even allowing for this fact, the data show that other agencies such as enzymes and ferments were active in bringing about many of the intra-chemical changes which caused the so-called ripening of the meats. Among these changes, it may be stated in general that the meats became: ( I ) more easily soluble in cold water as is shown by the increase of 8.9 per cent. of the watersoluble dry substance; (2) slightly lower in their per cent. of insoluble and total protein, apparently resulting in a subsequent increase in the nitrogenous organic extractives, and hence in flavor; (3) higher in the percentage of non-nitrogenous organic extractives which indicates the possible formation of lactic acid and some other products from the cleavage of the insoluble protein into the non-protein form; (4) higher in the percentage of nitrogenous and total organic extractives, total soluble nitrogen, and soluble inorganic phosphorus; and (5) lower in the ratios of the soluble non-protein nitrogen to the total protein nitrogen. I n comparing the data throughout for the uncooked beef in Experiments I and 2 , they indicate that the changes due to ripening which occurred during the hanging in cold storage apparently began in the first three weeks with an increase in the soluble inorganic phosphorus and its accompanying acidity, also with a decrease in the non-protein nitrogen and nitrogenous extractives and the total soluble nitrogen but with no changes in the percentage of protein; then, in the following three weeks, the meats did not increase appreciably in soluble inorganic phosphorus but rather in nonnitrogenous and nitrogenous organic extractives, in total soluble and non-protein nitrogen and in total soluble dry substance, while they decreased slightly in the insoluble and total protein, and also in the insoluble dry substance. INFLUENCE OF COLD STORAGE UPON POULTRY.
The purpose and plan of this experiment, number 3, were given in detail on pages 418-19 and suffice it to repeat briefly that drawn and undrawn frozen
431
chicken which were kept in cold storage for different lengths of time and fresh chicken were examined and studied in exactly the same manner as the uncooked beef which we have previously been considering. The several data are given in Tables IV, V, and VI calculated to the usual forms. I t will be recalled that the lots of chicken represented by laboratory numbers 2067, 2 I I I , and 2 I 12 were all procured at the same time and placed under the supervision of one of us, while those for laboratory numbers 2057 and 2110 were gotten at different times, each being sent to the laboratory at our request by two large wholesale firms. I n each case, in preparing the samples, the chicken were allowed to thaw in the ice box and were not put in water. Fresh Substance. The data of the edible lean meat, calculated. to the fresh substance, show in exactly the same manner as did that of the beef- the great variations in the moisture and fat content. This is especially noticeable in the case of samples, laboratory numbers 2067 and z I I I , where the percentage of water is 71.88 and 62.41, and that of fat is 6.41 and 18.15 respectively. The method of preparing the fowl for analysis might account in part for this variation in fat, since in each case all the lumps and layers of adipose tissue were carefully removed, but yet not in a quantitative manner. On the other hand, inasmuch as it seemed evident from the discussion upon beef that the variations in water content influenced the percentage of fat in a reciprocal manner, a fact which b'aitl also found to be true, the loss of moisture during storage would seem to help account for the increased fat content. I n comparing the two 120-day frozen samples of chicken with the fresh sample, the loss in the moisture in the edible meat is quite distinct, being 9.47 per cent. in the undrawn and 6.27 per cent. in the drawn, averaging a loss of 7.87 per cent., which is five times as great as the loss of the 4g-day refrigerated samples of beef. The fact that the flesh of the drawn chicken seems to contain more moisture than that of the undrawn samples cannot be taken up in this discussion until further investigations are made. I t would seem perhaps that the greater exposure of surface in freezing and thawing might be a partial explanation. The percentages of fat in the samples 2067, 2 1 1 1 and 2112 show that the frozen stored fowl, contain on an average 16.58 per cent. while fresh chicken 1
U.S Dept. of Agr , O&e of Exfieriment Stattons, Bull. 63.
432
T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y .
contains 6.41per cent., a difference of 10.17 per cent. The influence of this fact is also brought out in the amounts of insoluble and total dry substance, which are respectively 8.90 and 8.44 per cent. higher, for the cold storage fowl. I t is significant to note that the forms of protein are all lower in the frozen chicken, being 0 . 2 1 , 0.03 0.24, 1.21, and 1 . 4 4 per cent. for the coagulable, non-coagulable, total soluble, the insoluble, and total protein, meaning a percentage decrease of 16.0,21.0, 16.4, 7.2, and 7.9 respectively. The percentage of total
the changes taking place in storage since the samples were procured and prepared a t different times, kept in storage for unequal lengths of time, and were in themselves from different lots of chickens. However, these data show the interesting fact that they are not unlike the other three samples in regard to their nutritive value. This will become much more evident in discussing these data calculated to the fat-free basis and later to the same water content. I t is of importance to note in passing that the percentage of non-coagulable protein,
TABLE IV. CHEMICAL COMPOSITIONOF COLD STORAGE FLESH. EXPERIMENT 3. EDIBLE PORTION OF FROZEN CHICKEN. , (Calculated to Fresh Substance.) Frozen chicken. Description of sample. .Fresh chicken. Undrawn. Drawn. Undrawn. 2067 2111 2112 2057 Laboratory N o . . Time held in cold storage (days)......... 0 120 120 630 P. Ct. P. Ct. P. ct. P. ct. Water. 7 1 .88 62.41 65.61 73.12 Dry substance: Soluble 4.48 4.11 3.95 5.65 Insoluble. 33.90 30.49 21.62 Total 27.78 38.01 34,44 27.27 Protein: Soluble coagulable.. 1.32 1.04 1.18 2.09 Soluble non-coagulable.. 0.14 0.11 0.11 0.19 1.29 2.28 Total 1.46 1.15 Insoluble.. 16.68 15.66 15.29 16.26 Total 18.14 16.81 16.58 18.54 Organic extractives: 0.96 1.22 Nitrogenous 1.13 0.91 Non-nitrogenous.. 1.15 1.31 1 .os 1.36 2.0I 2.58 Total.. 2.28 2.22 15.02 5.15 Fat.. 6.41 18.15 Ash: 0.65 0.79 Soluble.. 0.74 0.74 0.18 0.21 Insoluble 0.21 0.09 Total 0.95 0.83 0.83 I.00 Nitrogen: As soluble coagulable protein.. 0.212 0.167 0.189 0.334 0.022 0.016 0.017 0.030 As soluble non-coagulablcprotein.. 0.234 0.183 0.206 0.364 Total 0.306 0.390 As soluble non-protein substance. 0.363 0.292 o ,597 0.475 0.512 0.754 Total.. 2.668 2 .SO6 2.447 2.602 Insoluble. Total 3.265 2.981 2.959 3.356 Phosphorus: Soluble inorganic.. 0.113 0.108 Soluble organic.. 0.018 0.022 Total 0.131 0.130 Insoluble. 0.047 0.050 Total 0.178 0.180
................
7
......................
............................... ............................. ...........
............................ ................. ........... ............................ ......................... ............................ ........................ ................... .......................... .............................. ........................... ........................... ............................ ....... .... ............................ ..... .......................... .......................... ............................
........................ .......................... .................................. ................................ ..................................
soluble and total nitrogen are also lower in the cold storage samples, being 0.104 per cent. for the former and 0.295 per cent. for the latter, and making a percentage difference of 17.4 and 9.0. As regar& the organic extractives, the non-nitrogenous form is practically the same, the nitrogenous form is 16.9 per cent. lower and the total is 7.4 per cent. lower. The ash shows a decrease in each form. I n studying the composition of the other two samples of frozen chicken, it is evident that nothing of a comparative nature can be ascertained as to
July, 1909
...... ...... ...... ...... ......
Drawn. 2110 ?
P. ct. 67.42 5.67 27.38
33.05 1.91 0.26
2.17 16.81
18.98
,
1.24 1 .so
2.74 10.44 0.76 0.13
0.89 0.306 0.040
0.346 0.396
0.742 2.691
3.433 0.118 0.017 0.I35
0.044 0 ,I79
which includes the albumoses, is practically the same in the 630-day frozen and the fresh samples of chicken, although the percentage of total soluble protein is higher in the former case. The results of the analyses of the poultry calculated to the fat-free basis are given in the following table, No. V. F a t - f r e e Substance.
It will now be of interest to consider these data calculated to the fat-free basis. Comparing the three samples, numbers 2 0 6 7 , 2 1 1 1 , and 2112, it
E-MiVETT A N D G R I N D L E Y ' O N C H E M I S T R Y OF F L E S H . will be seen that there is very little difference in the moisture content in contrast to that found for the data calculated to the fresh substance. The percentage of water in the drawn frozen fowl, 2 1 1 2 , is practically the same as the fresh chicken, being 7 7 . 1 6 and 77.08 respectively. The undrawn fowl, Z I 1 1 , has a percentage of moisture which is 1 . 2 2 per cent. lower than that of the fresh sample, and in turn this influences the percentage of insoluble and total dry substance and the insoluble and total protein, making them correspondingly higher. The per-
433
samples show the coagulable and total soluble forms to be slightly lower, the non-coagulable to be about the same, and the insoluble and total to be higher than those in the fresh sample. This fact shows again the effect of the influence of calculating the result to the fat-free basis, for upon the fresh basis, each form was distinctly lower in the frozen samples, The data for the other two samples of chicken, 2057 and 2 1 1 0 , show that they are just as nutritious as the first three. However, a direct comparison can best be made when they are all
TABLECHEMICAL COMPOSITION OF COLD STORAGEFLESH. EXPERIMENT 3.-EDIBLE PORTION OF UNCOOKED FROZEN CHICKEN. (Calculated to the Fat-free Basis.) Description of sample.
..................chicken. .Fresh
Laboratory N o . . ........ Time held in cold storage (days).
.
........ .............
Undrawn.
Drawn. 2110
P. Ct.
P. ct.
76.77
74.88
4.65 18.19
5.93 17.29
6.30 18.82
2 4 .I 4
22.84
23.29
25
1.26 0.13
2.19 0.20 2.39 17.07
18.67
75.86 5 .OO 19.14
P. ct.
a
I2
2.12 0.29
17.89 I9 .45
19.04
1.39 0.13 I .52 17.98
20.43
19.50
19.46
21.08
1.21 1.23
1.11 1.59
1.13 1.23
1.38 1.66
2.44
2.70
2.36
1.28 1.43 2.7r
3.04
0.79 0.23
0.90 0.11
0.76 0.21
0.83 0.22
0.84 0.15
I .o2
I.0I
0.97
I.0j
0.99
0.227 0.024
0.203 0.019
0.222 0.020
0.351 0.031
0.340 0.044
0.251
0.222
0.242
0.382
0.384
0.389
0.355
0.410
0.440
0.792
0.824
2.732
2.989
....
As soluble coagulable protein.
Drawn.
2057 630
P . Ct.
..................
.
Frozen chicken.
21 12 120 P . ct. 77.16
2111 120
.
................ ...............
Undrawn.
2067 0
Water. ............................... 77.08 Dry substance: Soluble. ............................ ' 4.80 Insoluble.. ............... 18.12 Total.. .. ............... 22.92 Protein, Soluble coagulable. 1.41 Soluble non-coagulable ............... 0 . 1 5 Total.. I .56 Total ............................ Organic extractives: Nitrogenous ........................ hTon-nit Total Ash: Soluble. ............................ Insoluble. ..........................
---~
I .39
2.4r
0.640
0.577
2.861
3.046
0.360 0.602 2.878
3.501 Ratio of non-protein to protein: In water extract.. . . . . . . . . . . . . . . . . . . 1: 0 . 6 4 In meats.. . . . . . . . 1: 8 . 0 0 Phosphorus: Soluble inorganic. . . . . . . . . . . . . . . . . . . . . . . . . . Soluble organic.. ..... ...... Tot a1 ..... ...... Insoliible ...... Total ............................ ......
3.623
3.480
3.524
3.813
1: 0 . 6 3 1: 9 . 2 1
1: 0 . 6 7 1: 8 . 6 7
1: 0 . 9 3 1: 7.59
1: 0.87 1: 7.67
0.057
0.127 0.026 0.153 0.059
0.216
O.ZI2
...... ...... ...... ...... ......
....
........ .............................
centage of the various constituents in the fresh and drawn fowl will be seen to be so close throughout thatlit is almost impossible to make any distinction between them. In xiew of this fact, i t will be of interest to note the effect of calculating the composition of the undrawn fowl to the same water content as the fresh chicken and thus eliminate any of the differences which might be due to moisture. Under the present condition, the different fornis of protein and nitrogen in the undrawn
0.137 0.022
0.159
0.131 0.019 O.Ij0
0.049 0.199
calculated to the same moisture content from the fat-f ree substance. Fat-jree Substance, Calculated to the Same Water Content. I n calculating these data to the same water content as that of the fresh unstored chicken, the results are in a condition which eliminates, as much as i t is possible, the effect of desiccation during storage, and brings them to a form which makes a direct comparison more logical in so far as a
434
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y .
study of the actual changes taking place during storage, other than drying, are concerned. Comparing the composition of the samples of the undrawn and drawn flesh, numbers 2 I I I and 2 I I 2 , the data show that the two samples are very much alike in the percentage of the various constituents. This is especially true of the water-soluble and insolub!e dry substance ; the non-coagulable, insoluble and total protein; the nitrogenous extractives, the total ash; the non-coagulable, insoluble and total
July, 1909
drawn poultry, the coagulable and water-soluble protein are higher, and in the undrawn poultry, the non-nitrogenous and total extractives are higher. If these two sets of data be compared with the one for the fresh unstored sample, it will be seen, on taking their average, that they are almost the same throughout. Further, of the two samples of stored flesh, the drawn and undrawn, the composition of the former approaches more nearly to that
TABLEVI.-CHEMICAL COMPOSITIONO F COLDSTORAGE FLESH. PORTION O F UNCOOKED FROZEN CHICKEN. (Calculated t o the Same-Water Content.) Frozen chicken. A Fresh 7 chicken. Undrawn. Undrawn. Drawn. Drawn.
EXPERIMENT 3.-EDIBLB
Description of sample
.............
................. . Water. .......................... Dry substance: Soluble. ....................... Laboratory N o . . Time held in cold storage (days). ,
..................... ....................... ............. ......... ..................... ..................... ...................... ................... ..............
Insoluble. Total Protein: Soluble coagulable. Soluble non-coagulable. Total.. Insoluble. Total. Organic extractives: Nitrogenous Non-nitrogenous.. Total.. Ash: Soluble. Insoluble. Total Nitrogen: As soluble coagulable protein.. As soluble non-coagulable protein Total As soluble non-protein substance Total Insoluble. Total. Ratio of non-protein to protein: In water extract.. I n meats.. Phosphorus: Soluble inorganic.. Soluble organic.. Total Insoluble. Total.
.....................
....................... ..................... .......................
..
....................... ....................... ...................... ......................
..............
....................
2067 0 P. ct. 77 .08
2111 120
Average of (2). Undrawn. P. ct.
Average of (2). Drawn. P . ct.
77.08
2112 120 P . ct. 77.08
2057 630 P . ct. 77.08
77.08
77.08
77 . 0 8
4.80 18.12
4.75 18.17
4.67 18.25
5.85 17.07
5.75 17.17
5.30 17.62
5.21 17.71
22.92
22.92
22.92
22.92
22.92
22.93
22.92
1.41 0.15
1.20 0.12
1.39 0.13
2.16 0.20
1.93 0.27
1.68 0.16
1.66 0.20
P Ct.
2110 ?
P . ct.
1.56
I .32
1.52
2.36
2.20
1.84
I .86
17.89
18.08
18.04
16.84
17.04
17.46
17.54
19.45
10.40
19.57
19.20
10.24
19.30
19.40
1.21 1.23
1.05 1.51
1.13 1.24
1.26 1.41
1.26 1.51
1.15 1.46
2.44
2.56
2.37
2.67
2.77
2 .61
1.21 1.36 2.57
0.79 0.23
0.86 0.10
0.76 0.21
0.82 0.22
0.77 0.13
0.84 0.16
0.76 0.17
1.02
0.96
0.97
1.04
0.90
I.00
0.93
0.227 0.024 0.251 0.389
0.193 0.018
0.223 0.020
0.346 0.031
0.310 0.040
0.269 0.025
0.266 0.030
0.211
0,243
0.377
0.350
0.204
0.296
0.337
0.361
0.404
0.402
0.370
0.382
0.640
0.548
0.604
0.781
0.752
0.664
0.678
2.861
2.892
2.888
2.696
2.727
2.794
2.807
3 .5OI
3.440
3.492
3.477
3.479
3.458
3.485
1: 0 . 6 4 1: 8 . 0 0
1: 0 . 6 3 1: 7.21
1: 0 . 6 7 1: 8 . 6 7
1: 0 . 9 3 1: 7 . 5 9
1: 0 . 8 7 1: 7 . 6 7
1: 0 . 7 8 1: 8 . 4 0
1: 0 . 7 7 1: 8 . 1 7
0.130 0.021
0.127 0.026
0.120 0.017
0.130 0.021 0.151 0.054 0.205
0.123 0.022
............. ....... ............... ....... ....... ....................... ....... ..................... ...................... .......
0.151
0.I53
0.054
0.059
0.205
0.212
nitrogen and the various forms of phosphorus. There is a tendency for the non-nitrogenous and total extractives and the soluble ash to be lower, and also a tendency for t,he coagulable protein, the insoluble ash and the total soluble nitrogen to be higher in the sample from the drawn fowl. However, these differences are slight and of such a nature that they show that no radical changes have taken place in either of the samples to the extent of affecting their nutritive value. I n the
....... ....... ....... .......
0 . I37
0.045
0.182
0.I45
0.052 0.197
of the fresh unstored sample. So closely do these three samples agree in their respective percentage chemical composition, that it may be stated from these data,first,that there is nodifference in the nutritive value between the flesh from drawn and undrawn fowl which has been kept in storage 1 2 0 days, and second, that the flesh from drawn and undrawn frozen fowl which has been held in cold storage for 4 months show that the chemical changes are exceedingly few and of such a nature as to indicate
EilIAVETT A N D GRliVDLE Y ON C H E M I S T R Y OF F L E S H . that they do not affect the nutritive value of the flesh. I n considering the data for the other two samples, 2 0 57 (undrawn) and 2 I I O (drawn), they will be found, when calculated to the same water content as that of the fresh unstored fowl, to be of very nearly the same composition for each constituent, and i t is interesting to note that, contrary to the other two samples of drawn and undrawn chicken flesh, the percentages of coagulable and soluble protein, and of non-nitrogenous and total extractives vary in a reciprocal manner, the protein in this case being higher in the undrawn sample, and the extractives being lower. If the respective two samples of drawn and undrawn flesh be averaged, i t will be seen that they are remarkably close in their percentage chemical composition, and again bring out the fact that there is no difference in the nutritive value of the two kinds of flesh, judging from their chemical composition. Finally, a comparison of the composition of the lean of the fresh fowl with that of the other two samples of stored chicken will be of value. While such a comparison cannot be made upon the basis that all three are from the same original lot, yet a general idea can be had as to the nutritive value of each. The data show that the stored samples are quite like those of the fresh sample, showing the greatest difference in having a higher percentage of water-soluble dry substance, of coagulable, non-coagulable and total soluble protein; and a correspondingly lower percentage of insoluble dry substance and insoluble protein. The percentage total protein of the various extractives, of the forms of ash, and of the total nitrogen are very nearly the same. From these statements i t is evident that the flesh from the chicken, which was kept in storage in one case as long as 630 days, is equally as nutritious as that of the fresh poultry. CONCLUSIOSS.
I n making a comparison of the chemical composition of fresh and cold storage flesh, the samples of which were procured under known conditions and either from the same animal or the same lot of animals, it was found : I . The method, as used in this laboratory, was sufficiently accurate to detect changes which occurred in flesh during cold storage. 2. I n the case of the refrigerated beef which was stored for 2 2 days, the averaged data indicate: ( a ) That there was no loss of water,
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( b ) That the percentage of the water-soluble solids, the soluble, insoluble and total protein, the non-coagulable protein, the nitrogenous and total organic extractives, the forms of ash, the total nitrogen and the total phosphorus, all remained practically unchanged. (c) That the only consistent real changes were a distinct increase in the total soluhle and the soluble inorganic phosphorus, being 8.0 and 17.9 per cent. respectively, and a decrease of 8.3 per cent. in the non-nitrogenous organic extractives. (d) That the nutritive value of the meat was una1tered. 3. I n the case of the refrigerated beef which mas stored for 43 days. the averaged data show: ( a ) That there was a loss of water amounting to 1.3 per cent. ( b ) That this loss of water, causing a proportional increase in all the other constituents, produced differences in some instances which were sufficient to overbalance the amounts in the fresh samples. (c) That the ratio of the non-protein to the protein nitrogen in the meats was lower. (d) That when allowance was made for the loss of moisture, the additional changes which occurred in cold storage consisted in a definite increase in the soluble dry substance, the nitrogenous, nonnitrogenous, and total organic extractives, the tvtal soluble nitrogen, the soluble inorganic phosphorus, and a slight increase in the soluble coagulable and total soluble protein nitrogen, and also in the insoluble and total nitrogen. (e) That the chemical changes in the 43-day refrigerated meats were greater in number than in the 22-day samples yet as far as nutritive value was concerned, the former showed an increase in the organic extractives and soluble protein, and but an insignificant decrease in the total protein, 4. The analyses of the frozen drawn and undrawn chicken showed, when allowances were made for the variations in fat and moisture, that there was almost no difference between the two, one being equally as good as the other. j . The analyses of the fresh and the frozen drawn and undrawn fowl, obtained from the same lot, showed that the latter changed but slightly and to such an extent that there was practically no difference in the nutritive value of the three, after correcting for the differences in the fat and moisture content. The authors wish to acknowledge the assistance of Messrs. J. M. Barnhart and I,. F. Shackell in
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T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING CHEiMISTRY.
connection with the analytical work of this investigation. THE LABORATORY OF PHYSIOLOGICAL CHEMISTRY. DEPARTMENT O F ANIMAL HCSBANDRY, UNIVERSITY O F ILLINOIS, URBANA.
----___ (CONTRIBUTION FROM DIVISIOXOF FOODS,BUREAUOF CHEMISTRY, I?.S. DEPARTMENT OF AGRICULTURE.)
COMPOSITION OF SCUPPERNONG, CONCORD, AND CATAWBA GRAPE JUICES, WITH SOME NOTES ON THE DETERMINATION OF TOTAL ACID.’ B y H. C. GORE. Received March 2 5 , 1909.
The use of unfermented grape juice is increasing, and fairly complete analyses of juices prepared from American varieties of grapes will probably be of interest to many. The juices considered here differ from the fresh musts in that they have been sterilized by heat and allowed to stand for a t least several weeks before analyzing. During this time considerable quantities of sediment were usually deposited consisting largely of crystals of potassium bi-tartrate. The supernatant liquor constitutes the grape juice. This method of allowing the juice to stand after having been sterilized, then racking off, is followed in the preparation of grape juice on a commercial scale. ,411 samples have been prepared by the writer or under his immediate direction and on as large a scale as practicable, so that the results might be strictly comparable with those which would be obtained under commercial conditions. I n all cases a t least 200 pounds of grapes were employed. I n the case of Catawba grape juice several tons of grapes were used, and although one analysis only of Catawba juice is given, the sample is probably thoroughly representative of the Catawba juice of this year in the Northern Ohio grape district. A statement of the general character of the three varieties of grapes as furnished by Mr. Geo. C. Husmann, Pomologist in charge of Viticultural Investigations of this Department, is given below. Scuppentor,g.-A variety of the Rotundifolia species. The designation Scuppernong” is a t present usually applied to all the lighter colored varieties of the Rotundifolia species and often even to the entire species. It is esteemed for its eating and wine-making qualities. Bunch of from six to twelve berries; berries large, thick skin. pulpy, fairly sweet, sprightly with a musky scent and flavor. I t is esteemed by some, repugnant to others. “
1
Published b y permission of the Secretary of Agriculture.
July, 1909
Very vigorous and productive in the South Atlantic and Gulf states. Mish.-A variety of the Rotundifolia species, Supposed to have been discovered by Mr. Albert Mish near the middle of the last century in the vicinity of Washington, N. C. It is at present one of the most extensively grown of the dark colored varieties of this species. Bunches small and straggling; berries ovoid, juicy ; flavor delicious and distinct; skin black, with numerous lighter colored specks. One of the best of the dark Rotundifolias for wine purposes. Very productive. James.-Variety of the Rotundifolia species. I t was discovered by Mr. B. M. UT. James, of Grindool, N. C., about 1866 near Grindool Creek, Grindool Post Office. Bunch, like all Rotundifolias, small and rather loose. Berries large, showy, round, juicy, slightly pulpy, sprightly, with the peculiar flavor of the Rotundifolia. Very prolific. I t is one of the most extensively grown of the dark varieties. Concord.--il variety of the Labrusca species. It originated with Mr. E. W. Bull, of Concord, Mass. He exhibited i t for the first time in September, 1853. Bunch above medium size, globular, black, thickly covered with beautiful blue bloom ; skin moderately thin, tender, cracks easily ; flesh moderately sweet, pulpy, tender. Time of ripening medium to late. Fruit of fair keeping quality, becoming insipid soon after being gathered. More fruit of this variety is sold as a table grape in our markets than of all other American varieties combined. At least 7 5 per cent. of the unfermented grape juice made from native species is of this variety. I t makes a light red wine of fair quality and a white wine can also be made by pressing the grapes immediately after they are crushed. This is unquestionably the best known and most extensively grown variety of our native species. Catawba.-A variety of the Labrusca species. Native of North Carolina and has its name from the Catawba River. Introduced to notice by Major John Adlum, Georgetown, D. C., in 1825. I t was for many years the standard w-ine grape of the country. On account of it being very subject to mildew, black rot and a so-called blight, and its late ripening in the northern and northeastern states it is not so much grown now as formerly. Bunch medium size, fairly compact, shouldered. Berries medium size, round, deep red, covered with lilac bloom ; skin moderately thick, flesh slightly pulpy, sweet and juicy with a rich vinous somewhat
