Vitamin Content of SPRAYlDRIED WHOLE EGG A. A. KLOSE, G . I. JONES, AND H. L. FEVOLD S. Department of Agriculture, Albany, Calif.
Western Regional Research Ilclboratory, U.
Spray drying of emulsified whole eggs, as practiced in most of the commercial drying units from which samples were obtained, has no significant destructiveaction on the vitamins contained in the egg-namely, vitamin A, vitamin D, thiamine, riboflavin, pantothenic and nicotinic acids. Vitamin A was found to be unstable during storage of dehydrated eggs; after 9 months 60 per cent was lost at 15" F., 75 at 70', and 80 at 98.6'. Pantothenic and nicotinic acids were quite stable during 9 months of storage of spray-dried whole eggs under the conditions used in these experiments. Only slight destruction of riboflavin occurred at 98.6" F. during the 9 months and essentially none at lower temperatures. Thiamine in spray-dried whole eggs was stable at 15" F. for 9 months) during the same period the losses were 46 per cent at 70' F. and 50 at 98.6'.
HE quantity of eggs apray dried in the United States has recently been greatly increased; in fact, a new industry has virtually been established. Information concerning the retention of vitamins during the drying and storing of eggs is, however, scanty. Since dried eggs will probably supply important fractions of the daily vitamin requirements to consumers, information concerning vitamin retention is very desirable. The present communication reports the results from experiments designed to supplement available information (3).
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STORAGE A N D VITAMIN ASSAYS
and in settled No. 2 tin cans. Those in barrels were subsampled and examined for their vitamin content after 1,3,6, and 9 months; those in tin cans were examined only after 9 months of storage. The samples were assayed for vitamin A, vitamin D, thiamine, riboflavin, pantothenic acid, and nicotinic acid. Three types of assays were used: biological for vitamins A and D, microbiological for pantothenic and nicotinic acids, and physical-chemical for thiamine, riboflavin, and vitamin A. Vitamin A was determined by the U. S. P.rat bioassay technique (6) with only minor modifications. The same vitamin was determined by the Carr-Price colorimetric procedure as modified by Koehn and Sherman ( d ) , using U. S. P. reference cod liver oil as the standard; since agreement of results from the two methods was good, some of the later results were obtained by the physicalchemical method only. Vitamin D was determined by the A. 0. A. C. chick assay method ( 1 ) ; thiamine and riboflavin were determined by the fluorometric method of Conner and Straub (2).
Pantothenic and nicotinic acids were determined by the microbiological methods of Pennington, Snell, and Willia.ms (6) and Snell and Wright (7), respectively. The pantothenic acid procedure was modified by substituting hydrochloric-acid-hydro!yzed casein for sulfuric-acid-hydrolyzed casein and by substituting a mixture of pure vitamins for the alkali-treated yeast extract. The vitamin mixture used in the assay was prepared by using 5 pg. thiamine, 5 pg. pyridoxin, 5 pg. nicotinic acid, 2 pg. riboflavin, and 0.1 pg. aminobenzoic acid in each 10 ml. of culture media. The metho$-of Snell and Wright for nicotinic acid was also slightly modified. Sulfuric-acid-hydrolyzed casein was replaced by hydrochloric-acid-hydrolyzed casein, and the mixture W?S composed of 5 pg. thiamine, 5 pg. pyroxidin, 1 pg. pantothenic acid, 2 pg. riboflavin, 0.1 pg. p-aminobenzoic acid, and 0.004 pg. crystalline biotin (free acid). Control assays showed that results obtained by the modified and original methods were in good agreement. VITAMIN RETENTION
Dehydration of whole liquid eggs DURINGDEHYDRATION. by the spray process did not result in any marked loss of vitamin A in a majority of the samples tested (Table 11). The apparent losses were, in general, well within the errors of the assay methods and cannot be considered significant, That losses may occur dur-
The emulsified whole eggs and the egg powders used in these investkations were obtained from several sources. Efforts were made To get samples of egg meats and powders which, when collected at the dryers, would be representative of the batches being processed. Ten of samples of emulsified and TABLE I. PROCESSING, MOISTURE,AND PROTEIN SaLTJBILI'PY DATA ON SPRAY-DRIED eggs were obtained from six commercial EGGSAMPLER dehydrators. Some engineering data Moiswere obtained on the temperature a t ture Protein Temgerature. which the eggs were deh drated, the Con- Soly F. Air Vol., nozzle ressures, and air vo?knes (Table Sample tent, Gra;: InEx-- I-'reasuie, Lb./Sq. In. cu.Ft./ No. Type of Egg % Spray Min. Dry E g g take h w i t Steam I). T i e eggs were transported to this laboratory while held at the tem2500-2800 27.000 120 160 2 Shell, storage 0.265 260 3.9 2500-2800 27,000 120 4 Shell oil-processed 160 3.5 0.277 260 peratures of soiid carbon dioxide, and 2500-2800 27,000 120 160 0.265 260 6 same' 3.1 after being received were immediately 2500-2800 27,000 160 120 0.273 260 8 Same 3.6 stored a t -30' F. until vitamin anal10 Same 4.5 0,296 260 160 120 2500-2800 27,000 12 Shell storage 6.5 0,271 283 142 ..... .... yses could be carried out. All sam14 JO%'froaen, 50% ples were examined to determine the .. shell 4.6 0,284 316 144 . .. , effect of spray drying on the vitamin 16 26.4%froren 73.6%fresb content of the eggs, and a selected shell 5.4 0:2m 508 ino ..... . .. sample was used in studies of vitamin 18 20% froren, lorr retention during storage. storage shet 70%freshshell 4.6 0.271 826 100 126 3200 9,000 Storage studies were carried out at 20 Shell 3 3 0 252 31.5 144 90 7000 8,500 three temperatures, 15", 70', and 98.6'F. The dried eggs were Rtored in lined brtrreh
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INDUSTRIAL A N D ENGINEERlNG CHEMISTRY
Vol. 35, No. 11
procedure (4). Table I11 and Fimre 1 show the close Vitamin Pantocomelaion of the data obRiboNico!inio thenio A, U. 8. P. Thitained from t h e two Units/ Vitamin D amine, flavin, Acid Aoid, Sample G . Dry A.O. A. C: pg./G. pg./G. pg./d. pg./G. methods in the majority of No. Sample Description Wt.4 Unita/G. Dry Wt. Dry Wt. Dry Wt. Dry Wt. s a m p l e s assayed. From 1 Emulsified whole egg 00 2.1 8 2.4 69 No 1 deh drated 53 1.4 2.8 8 2.1 65 the character of the curves 2 3 Emu1sified)wholeegg 38 3.6 7 .O 13 2.9 127 it is clear that the results 4 No 3 deh drated 38 3.0 7.4 13 2.3 127 5 Emulaifiedwhole egg 37 1.4 3.3 9 2.4 by the colorimetric method 6 No 5 deh drated 32 1.3 3.2 10 2.4 7 Emulsifiedwhole egg 6.9 12 8.1 142 42 3.9 are subject to less varia8 No 7 deh drated 39 3.3 6.9 12 2.6 137 tion than those obtained 9 Emulsifiedrwhole egg 38 1.0 3.3 8 2.9 00 10 No. 9. dehydrated 33 1.1 3 9 3 02 by the biological method; 11 Emulsified whole e g 39 3 .. 6 2 8 2 .. 1 0 71 12 No. 11 dehydratedl 41 2.7 12 2.1 73 a t the same time the two 13 Emulsified whole egg 44 3.4 10 2.2 80 sets of data are in such 14 No. 13 dehydrated 21 2.8 14 2.1 80 68 3.2 15 Emulsified wholee g 10 2.3 69 close agreement that the 16 No. 15 dehydratef 60 2.7 12 2.2 63 17 Emulsified whole e g 42 3.1 10 2.1 83 reliability of the chemical 18 No. 17 dehydrate8 38 2.7 11 2.1 81 method for the determim19 Emulsified whole egg 30 ... 20 No. 19 dehydrated 37 2.8 ii tion of this vitamin in eggs 0 Samples 1 to 10 were assayed for vitamin A by the biological method, and samples 11 to 20 by the ohemioal seems to be adequate. method. The losses of vitamin D in I powdered whole egg during storage were studied at two temperatures, 15" and ing dehydration is indicated by the values obtained by assaying 98.6O F. The values obtained by analysis of samples stored at 15" F. do not indicate loss (Table 111). A loss of 29 per cent waa samples 13 and-14. Comparison of the analytical data indicate8 that about 50 per cent of the vitamin A present in the liquid meats found in the powder held a t 98.6"F. for 9 months. Of the water-soluble vitamins studied, thiamine was found to of sample 13 was lost during dehydration. The reason for this be the least stable, as was to have been expected (Table 111). exception is not known. The solubility of the protein in thir No loss took place when the egg powder wm stored a t 15" F.for powder does not appear to be notably different from the protein 9 months; a t 70" F. very little destruction had taken place solubilities found in the other samples of powders examined during 6 months of storage, but a t the end of 9 months only about (Table I). The dsta indicate that vitamin D is retained during dehydra50 per cent of the original thiamine remained; at 98.6"F., 25 per cent was lost during the h t month of storage, followed by a tion (Table 11). The variations found are well within the experimental error of the chick bioassay method. gradual decrease which reached 50 per cent a t the end of 9 months. No loss of nicotinic or pantothenic acids occurred durThe data on the effect of spray drying on the water-soluble vitamins shows clearly that no loss of these vitamins took place ing storage of spray-dried eggs under the conditions of these exduring drying (Table 11). Slight variations in values for the periments. Any variation in the values is well within the experimental error of the method. Riboflavin was also found to be liquid eggs and the dehydrated products can be ascribed to errors comparatively stable during storage. A t 98.6" F. some loss took in sampling and other experimental errors inherent in the methplace, which amounted to 16 per cent after 9 months of storage. ods. All determinations were made in replicate. DVRINQ STORAGE. The data show that vitamin A was very DISCUSSION OF RESULTS unstable during storage (Table 111). When stored in barrels a t The results of these investigations, obtained from a study of 98.6"F. for 1 month, the loss, as measured by bioassay, amounted three samples of eggs, demonstrate that the vitamin A content of to 56.6 per cent of the amount originally present in the powder. At the end of 9 months of storage under the same conditions, 81.0 per cent of the vitamin was lost. The retention of the vitamin in powder stored TABLE 111. &TENTION OF VITAMINS IN DEHYDRATED EQQSDURINQ STORAQE' a t 70' F. was somewhat better than anth -P --_that a t 98.6" F. At the end of 6 months VitaminA U S P Vitamin D Rib* Niaotinio thepio Storage Unita/O. br; Wt.' A. 0. A. d. Thiamine, flavin Aoid Acid the loss a t 70" F. was approximately half BicColoriUnits G rg./C;. rdd. pg./d. Time, metrio Dry Dry Wt. 6$%. Dry Wt. Dry Wt. Mo. assay as great as that found a t the higher 0 53 52 1.4 2.8 7.9 2 . 1 05 temperature. Reduction of the storage Storage Temperature, 98.6' F. temperature to 15' F. served to retard the rate of destruction further, but probably not enough to warrant the use of the lower temperature, except possibly for a relatively short time followStorage Temperature, 70' F. ing packaging. Storage in sealed cans 1 68 48 2.9 2.9 33 resulted in somewhat improved reten24 2.4 tion. The differences in retention re11 1.6 19 sulted in the preservation of 10 to 15 Storage Temperature, 16' F. per cent more of the original vitamin 1 58 2.9 8.0 2.2 69 1.3 48 content in the canned as compared to 01 2.2 7.9 2.8 1.6 3 42 41 02 7.9 2 . 3 1.8 2.8 80 6 27 the barreled powders held a t the two 08 7.6 2.4 2.6 1.4 19 27 9 .. higher temperatures. 9) 28 In the storage studies vitamin A was 0 Sample 2 wgd wed in the storage studies. determined by the biological assay b These subsampla were #tored in sealed tin oam; all others were rtored in bur&. method and by the physical-chemical c
T A B L11. ~ RETENTION
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November, 1943
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at 15' F. had not undergone the marked changes that are usually indicative of LEGEND
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deterioration in quality. However, the vitamin A destruction was very marked. It is evident, therefore, that preservation of vitamin A is a separate problem and may not be related to maintenance of other desirable qualities of egg powders. A poseible explanation of the rapid oxidation of vitamin A in egg powders is found in the structure of the particles making up the powder. Microscopic examination showed that they were thinwalled, perforated, hollow globules. In effect,*eggpowders are made up of thin membranes which provide maximum exposure to the air and offer favorable conditions for oxidative processes. Two methods appear likely to be useful in retarding vitamin A destruction. One of them is the incorporation of antioxidants in the liquid egg prior to drying and in such fashion that the likelihoods of dissolving the antioxidant in the fat particles is assured; the other is that of mechanically compressing egg powders to such an extent that much of the air is expelled and the total surfaces are greatly reduced. It is possible that these two measures may be combined and their protective action accentuated. Experiments undertaken with the view of investigating the possible usefulness of such measures are in progress in this laboratory. Preliminary results indicate retarded destruction by some antioxidants and by compression. ACKNOWLEDGMENT
The authors are grateful to the Washington Egg and Poultry Association, of Seattle, Commercial Creamery Company, of Spokane, Swift and Company and Armour and Company, of Chicago, and Omaha Cold Storage Company, 3 6 9 of Omaha, for making available the samSTORAGETIME INMONTHS ples of eggs used throughout these investigations, and for valuable informaFigure 1. Effeet of Storage on Vitamin A Content of Powdered Detion and cooperation. Thanks are also hydrated Whole E g as Determined by U. s.P. XI Rat Bioassay Method (ab-) and by a %odMeation of the Cam-Price Colorimetric Assay due H. C. Douglas of the University of Method (below) Washington for his cooperation; J. C. Lewis and Elinor Shapiro of this laboratory for microbiological assays and colorimetric vitamin A determinations, mwotively; and F . T. Jopes, also of this laboratory, for -the dehydrated eggs may be markedly and rapidly reduced while the microscopic examination of the egg powders. eggs are in storage. This destruction is relatively rapid even under conditions which might be expected to stabilize the vitamin A. Even at 15' F. the major part of the vitamin A was destroyed in 9 months. The loss of thiamine may also be a matter of concern, when unfavorable conditions of storage obtain, as it amounted to approximately 50 per cent when the eggs were stored for 9 months at 98.6' F. Presumably the inactivation of vitamin A is due to oxidative processes. It waa apparent in these experimenta that the deatruction of vitamin A resulta from cbngee which are quite independent of those resulting in quality deterioration as indicated ,by ofi-odora and -flavom. The egg powder stored for 9 months
LITERATURECITED (1) h o c . of 0 5 c i a l
Aq. Chem., Officialand Tentative Methodr,
6th ed., p. 371 (1940). (2) Conner, R. T.,and Straub, 0. J., 13, 386 (1941).
IND. -0.
CRBM.,ANAL,ED..
(3) Hauge, 8. M.,and Zscheile, F. P., Science, 96,636 (1942). (4) Kwhn, C. J., and Sherman, W. C., J. BWl. Chena., 132, 627 (1940). (5) Penninpton, D., Snd, E.E.,and William, R. J., Ibid., 135,212 (194m. ,- - - -,. Pharmacopoeia of u. 5. A., 11th revision, p. 478, Easton, Penna., Mack Printing Co., 1936. (7) hell, E.E.,and Wright, L.D., J BWZ Chetn. 39 676 (1941).
(6)
