INDUSTRIAL AND ENGINEERING CHEMISTRY
292
CRUDEFIBER. Crude fiber is essentially a measure of the cellulose content. The average value for the ten brands of meal was 3.34 per cent, varying from 2.67 to 4.31 per cent. This should be a valuable determination in case of adulteration with shriveled or dry nuts, or vegetable products such as shells, roots, and stems. PROTEIN.The protein in the dry meal examined varied from 54.64 to 62.45 per cent with an average value of 58.65 per cent. This is equivalent to about 30 per cent (30.66) on the basis of the whole butter. REDUCINGSUBSTANCES.Qualitative tests showed the absence of reducing sugars before hydrolysis. Starch cellulose and pentosans were the polysaccharides found in the fat-free meal. After the hydrolysis, the reducing sugars calculated as glucose ranged from 22.77 to 29.92 per cent
Vol. 26, No. 3
(average 26.21) on the basis of the dry meal. This range in values was chiefly due to differences in starch content (14.46 to 21.43 per cent with an average value of 17.91). The amounts of pentosans, 5.30 to 6.81 per cent, varied less than one per cent from the average, 6 per cent. LITERATURE CITED Acree, S. F., Bur. Standards J. Research, 8 ,
(1) Kline, G. M . , and 23-35 (19.12’1. ~..~ (2) Thurston, “Pharmaceutical and Food Analysis,” p. 172. Van Nostrand, 1923. \----I
RECEIVED September 10. 1932. Presented in part before the Diviaion of Agricultural and Food Chemistry at the 84th Meeting of the American Chemical Society, Denver, Colo.. August 22 t o 26, 1932.
Vitamin C Content of Canned Tomato Juice RAY G. DAGGSAND A. G. EATON, Department of Vital Economics, University of Rochester, Rochester, N. Y.
T
OMATO juice has fast become a widely popular drink study of the vitamin C content of string beans shows growth and has been highly recommended because of its vita- curves of tremendous variability. For example, animal 9 min content. The present report is part of a study of on 18 grams of beans showed a gain of only a little over 100 the vitamin content of a local commercially canned tomato grams in 90 days while animal 8 on only 12 grams of beans juice and is intended as a demonstration of the fact that the showed a gain of about 400 grams for the same period. The tomato juice tested can be put up without suffering loss of main thesis of the paper, however, is devoted to a comparison vitamin C in the process of canning. It is also desired to of the Sherman method with that of Hojer ( 2 ) . Eddy preemphasize the technic of assay. sents evidence from his own studies of the validity of the There has been a considerable amount of work done on the Hojer method and states that it is a much more sensitive one vitamin content of raw tomatoes, strained tomatoes, tomato than the Sherman scoring system. juice extracted in the laboratory, and cooked tomatoes, but Hojer (8) states that Sherman’s method often gives variavery little on the vitamin C content of commercially canned tions of 100 per cent or more in determining the fully protectomato juice. Kohman, Eddy, and Gurin (4) have recently tive dose. Hojer introduced an assay method of his own that published an article on the canning of tomato juice without is dependent upon the pathological changes in the tooth vitamin C loss in which they have incorporated what they picture. He states that his method is just as good as that of term a “composite test” of five of the most popular brands of Sherman and that single animals may diverge a good deal commercial tomato juice. They compare three batches of from the others of the same group. He recommends the use experimental juice with canned tomatoes, sieved canned to- of “several” animals in each group. matoes, and the composite of five commercial tomato juices. Until such a time as we have a practical quantitative Doses of 3 and 5 cc. were fed, and two or three animals were method for the estimation of iLascorbic” acid, the writers used in each group. Concerning the five commercial juices believe that Sherman’s method of assay must be carried out on (fed in succession in 5-day intervals), they state: “Of the at least five to ten animals per group with the tabulation of six guinea pigs receiving the commercial tomato juice, only autopsy findings in order to justify in the slightest measure the one animal on the 5-cc. dosage was free from scurvy symp- drawing of even suggestive conclusions. The Hojer method toms. . . The four animals receiving canned tomatoes were also must be carried out on several animals in order to rule entirely free from scurvy symptoms, while the guinea pigs on out the individual variations that Hojer himself admits exist. the 3-cc. dosage of the juice made by sieving canned tomatoes Workers in the vitamin field are too prone to draw sweeping had no more than dubious symptoms of scurvy.” Three cc. ronclusions from too few experiments. The following experiments are short, but we feel that they of canned tomatoes were protective and 3 cc. of the juice made by sieving canned tomatoes were nearly protective are quite conclusive, especially in light of the work that has against scurvy, while 5 cc. of commercially canned tomato been done on canned tomato juice. juice did not protect. Some workers attach rather great importance to the growth EXPERIMENTAL PROCEDURE curves of guinea pigs in a vitamin C assay. The writers beGuinea pigs, weighing from 200 to 300 grams, were divided lieve this to be a fallacy. There is little evidence to show any specificity of vitamin C for growth such as is found for vita- into groups of seven each, according to weight and sex. min Bq. Growth is a complex phenomenon and is dependent Each guinea pig was placed in a separate screen-bottomed upon many factors, and therefore cannot in itself be used as a cage and supplied with distilled water from a glass cup. The criterion for any one. It is true that Sherman incorporated basal ration was fed ad libitum, and 20 grams of fresh cabthe growth curve in his assay method but only as a help in bage were supplied daily for the first week in order to accusthe interpretation of the results. Sherman distinctly points tom the animals to the cages and the ration, and to some out the individual variation in the growth curves and places extent to standardize the stores of vitamin C. The basal ration consisted of the following parts: the major emphasis on the autopsy findings. Eddy (1) in a
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riiatioii as i o tli reneral cuiidiiionn of tlie animals as t i l e esThe experimental period was 60 days, 30.0 nie all pigs surviving were chloroformed 9.0 1.0 ing to the method of Sfminan, LaMer, Freslr Patch's i:iid lirw oil \vas adlninistercd daily by arid Cnmpliell (i),and the degree of scurvy mas expressed pipet. The ratioti was mixed in srnull batches o i i w a weck iiuinerically by adding up tlic plus signs. It is genrrally erist,onittry to rnn vitamin C assays a little nnd stored in the ice box. At, the end of tlie first k the cnbhage w w withdrawn longer tlian t,liis, hut,, since it was desired t o make a direct and graded doses of toniato juice w r e given, as indicated in comparison of the caiiiied t,orn:ito juice with tlie fresh fieldtlie tables. The tomato jnice was administered daily dircctly ripcneil toniators from wliicli the juice I ~ Smade, it vas necosinto the nionf.li by pipet, as preliminary trials slio\vad t,hat, sary to s l m t e n the experiniental period. The m-iters conthe animals monld riot consume tlie juice readily rnoiigli from ,siiler a direct corngari;on T d I i fresh toniat.oes of far more importance tlian the f c v extra days of experimental feeding. cnps t o pre-ient the loss of vitamiir C by oxidation. Weights were rtwrded daily in order to obtain ~ o m illfore 811 of tile tunmtoos were of t,lie Jolin I3aer variety. The (PiililiNl)
Wheat brsn Skim milk avsder (lierted m d ~ : , i l t , ~ t ~ y at n 110' for 3 hours. stirred esi.ti I h U r ) Ijuttei 1st (freshly ciiuriiett) Sodium chloride
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I N D U S T R I A 1, A S D E N G I N E E R I N G C H E M I S T R Y
Vol. 26, No. 3
TABLE I. SEGATIVE CONTROLP TIME
REQL-IRED
-
T O SHOT\
SIGICSOF D U R A T I O N SOREJOISTS OF LIFE Daus Days
BONYS T R V C T ~ R E Jaw
+++ +++ +++ +++ +++ ++t ++-
Teeth
7 -
Ribs
Joints
Ribs
+++ +++ +++ +++ +++ +++
+++ +++ +++ +++ +++ +++
+++ +++ +++ +++ +-+ ++
__ H E X O R R H A G E S Intestines
? 23 T++ ? 25 23 i 24 ++$ 22 24 20 31 +t +T+ +++ ++23 34 AI,. 19 26 A l o s t of t h e animals did not live long enough to sholi major macroscopic t o o t h changes, looseninp, e t c
1: 19 15 17
i 1,
+++
canning of the juice began in tbe last week of August and continued into the third week of October, the tomatoes being supplied fresh daily. This time lacked about 10 days of the 60-day experimental period. I n order to supply fresh tomatoes for these last 10 days, a large number of tomatoes from the last few days of picking were individually wrapped in paper and stored in the ice box a t a temperature a little above freezing. Choice, firm, nondeteriorated, nonfrozen tomatoes mere selected daily from these stored tomatoes for the experiment. The canned tomato juice was prepared in the follo~ving manner at the packing house: The tomatoes were washed, and firm, well-ripened ones were selected, cored, and extracted by a screw-type tomato juice extractor. The juice was heated in vacuum (below pasteurization temperature) and the cans were filled under vacuum. (The 1932 pack was not canned under vacuum but was heated in vacuum.) After the cans were sealed, they were pasteurized, labeled, and packed. Cans from each day’s pack were taken to the laboratory and used for that day’s feeding. The fresh tomatoes were brought to the laboratory and kept in the ice box for a few hours before extracting. The tomatoes were cored and pressed through a kitchen sieve by hand while still cold. This extracted juice was immediately centrifuged in order to express the air and was fed a t once. This fresh ton-ato juice compared favorably in color and consistency with the canned juice, the only difference being a finer suspension of pulp in the canned juice owing t o the use of a finer extracting screen. All of the autopsies were performed by the same person. The results are summarized in Tables I and 11. The sum of the plus signs is shown as an index of tbe degree of scurvy. The actual Sherman score as suggested by Kenny (3) has not been calculated for those animals living less than the experimental period, Twenty-four is the maximum number of plus signs and indicates extrerely severe s c u n y . Only the averages of each group of seven animals are gil-en, along with one illustrative table of the negative controls in order to show the method of tabulation. I n the canning of the 1932 pack the additional production of a vacuum during canning was eliminated. It xvas of qome concern to learn whether or not this would appreciably alter the vitamin C content of the freshly packed juice. Tl-e 1932 juice was tested in the same manner as the 1931 juice, and Table I1 shows the average results. TABLE11.
-AVERAGE SCORE OF P A C K S O F T W O Y E A R S C4NNED J U I C EDOSE FRESHJ I I C E DOSE 1 cc 2 cc 3 cc 4 c c 1 cc 2 r c 3 cc 4 cc. 1931 a v score 15 3 7 5 2 8 0 16 5 14 8 3 1 0 5 . 8.5 3 0 . 1932 av score . 5 1 2 1
When the animals of the 1932 experiment were autopsied, the lower jaws 1%-erecarefully removed, cleaned, decalcified, and fixed, and histological sections were made of the incisors. The sections were carefully examined, the procedure being essentially that of the Hojer method ( 2 ) with the exception
+++ +++
++ +++
Joints
+++ +++ +++ ++++ +++ +++
lluscles
+
+
+
+ + +
+++
++ +$
+++ ++
SCORE
+(SUM SIQNS) OF
SCORE 21 21 21 21 18 19 23 20.5
that the animals had been on experiment 60 days instead of the usual 2 weeks. (Hojer suggests that the method may be “made sharper by letting the animals live longer than 2 weeks.”) KOattempt was made to score the findings according to the Hojer method. The pathological findings in the teeth offered an additional check on the vitamin C content of the tomato juice. Figure 1 gives characteristic findings for the different groups of animals. Figure 1A shows a complete cross section of a lower incisor of a guinea pig receiving no tomato juice and dying of scurvy in 29 days. The pathological examination reveals an almost complete disintegration of the pulp tissue and the presence of only a thin band of dentine bounded on its pulpal border by a layer of osteodentine. The disappearance of the odontoblasts is typical of complete scorbutus. The remaining photographs are of slightly greater enlargement and show only a part of the cross section. I n B ( 2 cc. fresh juice) the odontoblasts are shown to be present but are shortened and irregular in appearance. The pulpal border of the layer of defective dentine is somewhat irregular and also s h o w a distinct line of demarcation from the old dentine ( d ) . The defective dentine is indicative of faulty calcification because of the lack of fusion of the calcospherites formed by the odontoblasts. The inner layer of dentine (n. d . ) unlike the outer layer of older dentine (d) lacks the normal tubular appearance of true dentine. Figure IC ( 2 cc. canned juice) presents conditions similar to those found in B. There is, however, a slightly greater dliorder among the odontoblasts and a greater degree of irregularity of the pulpal border of the new dentine. The degree of difference betmeen B (2 cc. fresh juice) and C ( 2 cc. canned juice) can hardly be considered significant because such a difference occurs as individual variation within the group. Figures 1D (3 cc. fresh juice) and E (3 cc. canned juice) show similar tooth pictures. There is a slightly greater di5integration in the canned than in the fresh. As the higher doses are reached, the diPtinct line of demarcation between the t-ro dentine layer> is lacking, and they tend to merge one into the otl.er. There is still some engorgement of the blood vessels and vacuolation in the pulp and irregularity of the odontoblasts. Figure 1F is taken from a group receiving 5 cc. of canned juice and is illustrative of a practically normal tooth picture. The dentine has t1.e normal tubular appearance. Tbe laminations of the dentine do not indicate an abnormal condition. The slight irregularity of the odontoblasts shown in this particular section is probably due to tearing during sectioning.
DISCUSSIOK OF RESULTS Table I slion s that the negative controls developed scurvy on the average a t 19 days and died a t 26 days. I n the 1931 pack, 4 cc. of fresh or canned juice 17-ere necessary to afford complete protection, but 3 cc. of the canned as well as the fresh juice gave very low scurvy scores. Only in the 2-cc. groups is the canned juice distinctively less protective than
March. 1931
1 N D US TR Ih L
hN D
E N G I N E E E1 I N G C 13 E M I S T R Y
the fresh, and the wide difference here might well be due to animal variation. S o such variation occurred in the 2-cc. group for the 1932 pack or in any of the other dosages. The 1-cc. group.shows only a slightly higher score for the canned juice. It is clearly evident that there is a slight destruction of vitamin C in the canned juice in the process of packing, but this is slight indeed when one considers the ease with which the vitamin is oxidized. I t is evident from Table I1 (1932 pack) that sealing the cans under an additional mechanical vacuum is not essential. The results shorn slight destruction of vitamin C in the canned juice, but it is of about the same order of magnifude as in tlie 1931 test. The tooth sections confirm the findings of the Shernian method for the 1932 pack and serve as an additional check on the vitamin C content of the canned tomato juice as compared with the fresh. The work indicates only a slightly log-er content of vitamin C in this particular brand of commercial tomato juice as compared with the fresh tomatoes from which i he juice was commercially extracted. The authors do not wiih to iniply
293
by this study that all brar?ds of comniercially canned tomato juice are satisfactory in vitamin C content just because this one brand proves so. There are undoubtedly inany inferior products on the market. Seither do they want the reader to infer that the brand teqted ]:ere k tlie only satisfactory tirand available.
A~CK~owLEDGJIE” The sections of the incisors of the ariiiiials in tlie 1932 experiments were exaniined by C. I). 31. Day, Rockefeller Dental Fellow in the Department of Vital Economics, University of Rochester. I,ITERAITJliE C I T E D
(1) Eddy, W. H., .im.J . Pub. Health, 19, 13OY (1929). (2) Hojer, A,, Brit. J. E.rptl. Path., 7, 386 (1926). (3) Kenny, C. L., Dissertation, Columbia University, New York, 1936. (4) Kohman, E. F., Eddy, W. IT., and Gurin, C. Z.,IND. EXQ. CHEM.,25, 652 (1933). (5) Sherman, H. C . , LaMer, V. I
