- Email: [email protected]
The Niacin Content of Fresh and Stored Shell Eggs*
T h e Niacin Content of Fresh and Stored Shell Eggs* ROBERT JOHN EVANS, HELEN A. BUTTS AND J. A. DAVIDSON Departments of Agricultural Chemistry and Poultry Husbandry, Michigan State College, East Lansing, Michigan
N
IACIN (nicotinic acid) is of extreme, importance in nutrition. A dietary deficiency of niacin may result in pellagra in man (Fouts et al. 1937), black tongue in dogs (Elvehjem et al. 1937), and black tongue and perosis in chicks (Briggs et al. 1942, 1943). The niacin level in eggs is low. Values of 17 to 21 ^g. per yolk and 56 to 64 ng. per albumen (Dann and Handler, 1941), 0.73 to 0.90 ng. per gm. of whole egg (Snell and Quarles, 1941), 0.76 /jg. per gm. of albumen and 0.35 tig. per gm. of yolk (Teply et al., 1942), and 0.72 Mg. per gm. of whole egg (Cheldelin and Williams, 1942) have been reported on a fresh egg basis. When compared with values of 20 to 100 fig. per gm. of grains and meats, eggs are seen to be relatively unimportant as a source of niacin in the human diet. The National Research Council gives a tentative recommendation for the niacin intake of an adult as 15 mg. (Gortner, 1949). No data have been published on changes in the niacin content of shell eggs during storage, but the niacin content of fertile eggs increases during incubation (Dann and Handler, 1941; Snell and Quarles, 1941). Losses of protein during cold storage of shell eggs have been reported (Evans, Davidson and Butts, 1949). * Published with the approval of the Director of the Michigan Agricultural Experiment Station as Journal Article No. 1169.
EXPERIMENTAL
Laying White Leghorn hens were kept in individual laying cages. The ration fed consisted of ground corn 34.5, ground oats 20.0, wheat bran 15.0, flour middlings 10.0, dehydrated alfalfa 3.0, meat scraps 3.0, dried milk 2.0, fish meal 2.5, soybean oil meal 2.5, ground oyster shell flour 5.0, steamed bone meal 1.5, salt 0.6, and fish oil (400D and 3,000 A) 0.4. Eggs were gathered daily during March 1949, marked with hen number and date, and placed in cold storage at 0°C. or assayed for niacin. Three eggs from each of ten hens were used immediately for niacin assay, and 12 were stored in a carton holding one dozen eggs. The cartons of eggs were placed in a fiber egg case and stored in a walk-in refrigerator at 0°C. Samples of three eggs each were taken for niacin assay after 3, 7, and 12 months of storage. Three eggs from each hen were hard boiled, cooled under running water, and the albumens and yolks carefully separated and weighed. The yolks of the three eggs were well mixed as were the albumens. Two 20 gm. samples of each were weighed into 125 ml. Erlenmeyer flasks, 50 ml. of 1.0 N hydrochloric acid were added, the flasks were covered with small beakers, and the contents were hydrolyzed by autoclaving for 30 minutes at 15 lb. pressure. The hydrolysates were neutralized, made to a volume of 200 ml., filtered, and the filtrate stored under
132
Downloaded from http://ps.oxfordjournals.org/ at Kokusai Hoken Keikakugaku (UNIV OF TOKYO) on May 18, 2015
(Received for publication July 19, 19S0)
133
NIACIN CONTENT OF EGGS
toluene in the refrigerator until ready for assay. Niacin assays were made microbiologically using Lactobacillus arabinosus 17-5 as the organism and the medium and procedure of KrehL Strong and Elvehjem (1943). RESULTS AND DISCUSSION
TABLE
1.-
Hen
i the niacin content of during storage of shell eggs (jug. per egg) 3 month 7 month .12 month old old old eggs eggs eggs
No.
Fresh eggs
4184 4185 4187 4188 4189* 4190 4191 4192 4193 4194*
29.9 30.2 34.9 31.9 (29.4) 33.7 31.2 31.1 27.2 (37.6)
29.1 26.5 29.5 28.3 (21.9) 31.5 29.6 28.3 28.3 (37.6)
25.1 24.5 28.4 24.9 (24.8) 27.0 26.5 25.9 24.4 (31.0)
29.5 32.8 33.6 30.0 (57.7) 33.4 36.4 30.4 31.0
Ave.*
31.3
28.9
25.8
32.1
—
* Values for hens No. 4189 and 4194 were not included in the average values, because the 12month old eggs from hen No. 4189 were slightly moldy, and no usuable 12-month old eggs were obtained for hen No. 4194. TABLE 2.—Changes in the niacin content of egg albumen during storage of shell eggs (jug. per albumen) Hen
3 month 7 month 12 month old. old old eggs eggs eggs
No.
Fresh eggs
4184 4185 4187 4188 4189* 4190 4191 4192 4193 4194*
27.5 27.2 32.1 29.0 (26.8) 31.2 28.4 28.2 24.4 (34.7)
25.9 22.7 26.3 25.1 (19.4) 27.9 26.4 24.7 24.8 (33.9)
21.5 20.4 24.7 20.9 (20.7) 22.7 22.9 20.8 20.4 (26.5)
22.8 25.3 27.2 19.0 (35.3) 22.4 24.9 22.5 16.0
Ave.*
28.5
25.5
21.8
22.5
* See footnote Table 1.
—
Hen No. 4184 4185 4187 4188 4189* 4190 4191 4192 4193 4194* Ave.*
Fresh eggs
3 month 7 month 12 month old old old eggs eggs eggs
2.4 3.0 2.8 2.9
3.2 3.8 3.2 3.2
3.6 4.1 3.7 4.0
(2.6)
(2.5)
(4.1)
2.5 2.8 2.9 2.8
3.6 3.2 3.6 3.5
4.3 3.6 5.1 4.0
(2.9)
(3.7)
(4.5)
2.8
3.4
4.1
6.7 7.5 6.4 11.0 (22.4) 11.0 11.5
7.9 15.0 —
•
9.6
* See footnote Table 1. TABLE 4.—Changes in the niacin content of albumen during storage of shell eggs (Mg. per gm.) 3 month 7 month 12 month old old old eggs eggs eggs
Hen No.
Fresh eggs
4184 4185 4187 • 4188 4189* 4190 4191 4192 4193 4194*
0.94 0.91 0.91 0.98 (0.90) 0.93 0.89 0.98 0.87 (0.93)
0.86 0.78 0.78 0.82 (0.69) 0.85 0.84 0.86 0.87 (0.91)
0.74 0.71 0.74 0.74 (0.71) 0.73 0.74 0.79 0.73 (0.80)
0.83 0.88 0.83 0.80 (1-47) 0.79 1.01 0.86 0.81
Ave.*
0.93
0.83
0.74
0.85
—
* See footnote Table 1.
jug. were in the yolk (Table 3). These values are much lower than the 56 to 64 ng. of niacin per albumen and the 17 to 21 ng. per yolk obtained by Dann and Handler (1941) using a chemical method of assay. However, the average values of 0.93 Mg- per gm. of albumen, 0.16 ng. per gm. of yolk, and 0.66 ng. per gm. of whole egg given in Tables 4, 5, and 6 for fresh eggs agree better with the literature values obtained by the microbiological assay procedure. The values for fresh whole eggs presented in Table 6 are all slightly lower
Downloaded from http://ps.oxfordjournals.org/ at Kokusai Hoken Keikakugaku (UNIV OF TOKYO) on May 18, 2015
Fresh eggs contained an average of 31.3 Mg- of niacin per egg (Table 1); 28.5 fig. were in the albumen (Table 2), and 2.8
TABLE 3.—Changes in the niacin content of egg yolk during storage of shell eggs (jtg. per yolk)
134
ROBERT JOHN EVANS, HELEN A. BUTTS AND J. A.
than the 0.72 fig. per gm. reported by Cheldelin and Williams (1942) or the 0.73 to 0.90 tig. obtained by Snell and Quarles (1941). Teply et al. (1942) found less niacin in the albumen (0.72 fig. per gm.
3 month 7 month 12 month old old old eggs eggs eggs
Hen No.
Fresh eggs
4184 4185 4187 4188 4189* 4190 4191 4192 4193 4194*
0.15 0.15 0.16 0.17 (0.14) 0.16 0.17 0.18 0.17 (0.14)
0.19 0.19 0.17 0.19 (0.14) 0.20 0.19 0.22 0.19 (0.18)
0.22 0.19 0.19 0.23 (0.21) 0.23 0.21 0.29 0.22 (0.23)
0.39 0.34 0.32 0.50 (0.93) 0.49 0.52 0.42 0.59
Ave.*
0.16
0.19
0.22
0.45
loss of niacin from the albumen was 24 percent, a decrease of 6.7 fig. per egg (Table 2). Part of the loss from the albumen was due to the transfer of 1.3 fig., of niacin to the yolk (Table 3). The loss of niacin was accompanied by a decrease of the niacin concentration in the albumen from 0.93 fig. per gm. to 0.74 fig. per gm. (Table 4). The niacin concentration in the yolk increased from 0.16 fig. per gm. to 0.22 fig. per gm. (Table 5). The above results are of interest because Evans and Davidson (1951) observed an 8.3 percent increase m yolk weight and a 7.4 percent decrease in albumen weight during seven months of cold storage. The transfer of water from the albumen to the yolk is accompanied by a transfer of niacin.
—
The niacin values for the eggs of hens No. 4189 and No. 4194 are not included in the average values give in the tables. * See footnote Table 1. Eggs from hen No. 4189 that had been TABLE 6.—Changes in the niacin content of whole eggstored for twelve months contained some during storage of shell eggs mold growth. The mold apparently synG*g. per g m.) thesized some niacin, because the twelve month old eggs contained 57.7 jug. of 3 month 7 month 12 month Hen Fresh old old old niacin compared to the 29.4 fig. in the eggs No. eggs eggs eggs fresh eggs. Recent work (Rosen et al., 0.62 0.55 0.66 4184 0.66 1946) has indicated tryptophan as a pre0.61 0.53 0.49 0.65 4185 cursor for the biological synthesis of 0.54 4187 0.66 0.56 0.63 0.60 0.55 4188 0.70 0.65 niacin. Although the niacin content of eggs (0.48) (0.51) (1.20) 4189* (0.61) is low, fresh eggs contain 65 to 74 mg. of 4190 0.68 0.62 0.55 0.66 0.55 4191 0.65 0.61 0.77 tryptophan per egg (Evans et al., 1949) 0.63 4192 0.70 0.59 0.68 which should be an abundant source from 0.53 4193 0.60 0.69 0.61 4194* (0.67) (0.66) (0.59) — which molds could synthesize niacin. None of the twelve month old eggs of hen 0.54 0.66 0.60 0.67 Ave.* No. 4194 were usable; all had to be dis* See footnote Table 1. carded as spoiled, because the yolks and compared to 0.93 fig. reported in Table 4) albumens were mixed together. Many of and more in the yolk (0.35 ng. per gm. the other twelve month old eggs had to be compared to 0.16 ng. reported in Table 5) discarded because of spoilage. As a result the values for the twelve month old eggs than we did. During the first seven months of cold of four hens were based on two eggs, and storage an 18 percent average loss of only one egg was available for hen No. niacin from the whole egg occurred, the 4188. average values decreasing from 31.3 to 25.8 fig. per egg (Table 1). The average
The temperature regulator of the walkin refrigerator did not work satisfactorily
Downloaded from http://ps.oxfordjournals.org/ at Kokusai Hoken Keikakugaku (UNIV OF TOKYO) on May 18, 2015
TABLE 5.—Changes in the niacin content of egg yolk during storage of shell eggs Og- per gm.)
DAVIDSON
135
NIACIN CONTENT OF EGGS
The data indicate that during cold storage there is a gradual loss of niacin from the shell egg. The niacin loss is of little importance in nutrition, because eggs supply a negligible amount of the dietary requirement for niacin. Contrasted to the loss of niacin from shell eggs stored in the cold is the increased niacin content of incubated fertile eggs (Dann and Handler, 1941; Snell and Quarles, 1941) and the increased niacin content of eggs stored under conditions favorable for microbial infection such as was observed in the twelve-month old eggs. SUMMARY
Fresh shell eggs contained on the average 31.3 fig. of niacin per egg or 0.66 ng. per gm. Most of the niacin (28.5 jug. or 0.93 fig. per gm.) was in the albumen, and only 2.8 fig. (0.16 fig. per gm.) was in the yolk. An average loss of 5.5 fig. of niacin occurred during seven months of cold storage. Despite a loss of water from the eggs the niacin concentration also decreased to 0.54 fig. per gm. The average
niacin content of the yolks of seven month old eggs was 4.1 fig. with a concentration of 0.22 fig. per gm. of yolk and that of the albumen was 21.8 fig. (0.74 fig. per gm.). REFERENCES Briggs, G. M., Jr., T. D. Luckey, L. J. Teply, C. A. Elvehjem and E. B. Hart, 1943. Studies on nicotinic acid deficiency in the chick. J. Biol. Chem. 148: 517-522. Briggs, G. M., Jr., R. C. Mills, C. A. Elvehjem and E. B. Hart, 1942. Nicotinic acid in chick nutrition. Proc. Soc. Exptl. Biol. Med. 51: 59-61. Cheldelin, V. H., and R. J. Williams, 1942. The B vitamin content of foods. Univ. Texas Pub. 4237: 105-124. Dann, W. J., and P. Handler, 1941. Synthesis of nicotinic acid by the chick embryo. J. Biol. Chem. 140: 935-936. Elvehjem, C. A., R. J. Madden, F. M. Strong and D. W. Woolley, 1937. Relation of nicotinic acid and nicotinic acid amide to canine black tongue. J. Am. Chem. Soc. 59: 1767-1768. Evans, R. J., and J. A. Davidson, 1951. The choline content of fresh and stored shell eggs. Poultry Sci. 30: 29-33. Evans, R. J., J. A. Davidson, S. L. Bandemer and H. A. Butts, 1949. The amino acid content of fresh and stored shell eggs. II. Arginine, histidine, lysine, methionine, cystine, tyrosine, tryptophan, phenylalanine, and proline. Poultry Sci. 28: 697-702. Evans, R. J., J. A. Davidson and H. A. Butts, 1949. Changes in egg proteins occurring during cold storage of shell eggs. Poultry Sci. 28: 206-214. Fouts, P. J., O. M. Helmer, S. Lepkovsky and T. H. Jukes, 1937. Treatment of human pellagra with nicotinic acid. Proc. Soc. Exptl. Biol. Med. 37: 405^07. Gortner, R. A., 1949. Outlines of Biochemistry, Third Edition, New York. John Wiley and Sons, Inc. Krehl, W. A., F . M. Strong and C. A. Elvehjem, 1943. Determination of nicotinic acid. Modifications in the microbiological method. Ind. Eng. Chem., Anal. Ed. 15:471-475. Rosen, F., J. W. Huff and W. A. Perlzweig, 1946. The effect of tryptophan on the synthesis of nicotinic acid in the rat. J. Biol. Chem. 163: 343-344. Snell, E. E., and E. Quarles, 1941. The effect of incubation on the vitamin content of eggs. J. Nutrition 22: 483-489. Teply, L. J., F. M. Strong and C. A. Elvehjem, 1942. The distribution of nicotinic acid in foods. J. Nutrition 23: 417-423.
Downloaded from http://ps.oxfordjournals.org/ at Kokusai Hoken Keikakugaku (UNIV OF TOKYO) on May 18, 2015
for a period between the time that the seven and the twelve month old eggs were taken out of storage. The temperature at one time went low enough to freeze and crack many of the eggs, and then it went high enough to start mold growth. Many eggs deteriorated to such an extent that the vitelline membrane ruptured before or during the boiling of the egg, and the albumen and yolk were mixed together so that the eggs could not be used. Even the eggs that were not cracked or that did not have ruptured membranes were probably affected by the adverse temperatures. Because of these conditions it is felt that the data from the twelve-month old eggs can not be considered as typical of what occurs during the proper cold storage of shell eggs. The rise in niacin content of the twelve month old eggs was probably caused by microbiological synthesis.
N
IACIN (nicotinic acid) is of extreme, importance in nutrition. A dietary deficiency of niacin may result in pellagra in man (Fouts et al. 1937), black tongue in dogs (Elvehjem et al. 1937), and black tongue and perosis in chicks (Briggs et al. 1942, 1943). The niacin level in eggs is low. Values of 17 to 21 ^g. per yolk and 56 to 64 ng. per albumen (Dann and Handler, 1941), 0.73 to 0.90 ng. per gm. of whole egg (Snell and Quarles, 1941), 0.76 /jg. per gm. of albumen and 0.35 tig. per gm. of yolk (Teply et al., 1942), and 0.72 Mg. per gm. of whole egg (Cheldelin and Williams, 1942) have been reported on a fresh egg basis. When compared with values of 20 to 100 fig. per gm. of grains and meats, eggs are seen to be relatively unimportant as a source of niacin in the human diet. The National Research Council gives a tentative recommendation for the niacin intake of an adult as 15 mg. (Gortner, 1949). No data have been published on changes in the niacin content of shell eggs during storage, but the niacin content of fertile eggs increases during incubation (Dann and Handler, 1941; Snell and Quarles, 1941). Losses of protein during cold storage of shell eggs have been reported (Evans, Davidson and Butts, 1949). * Published with the approval of the Director of the Michigan Agricultural Experiment Station as Journal Article No. 1169.
EXPERIMENTAL
Laying White Leghorn hens were kept in individual laying cages. The ration fed consisted of ground corn 34.5, ground oats 20.0, wheat bran 15.0, flour middlings 10.0, dehydrated alfalfa 3.0, meat scraps 3.0, dried milk 2.0, fish meal 2.5, soybean oil meal 2.5, ground oyster shell flour 5.0, steamed bone meal 1.5, salt 0.6, and fish oil (400D and 3,000 A) 0.4. Eggs were gathered daily during March 1949, marked with hen number and date, and placed in cold storage at 0°C. or assayed for niacin. Three eggs from each of ten hens were used immediately for niacin assay, and 12 were stored in a carton holding one dozen eggs. The cartons of eggs were placed in a fiber egg case and stored in a walk-in refrigerator at 0°C. Samples of three eggs each were taken for niacin assay after 3, 7, and 12 months of storage. Three eggs from each hen were hard boiled, cooled under running water, and the albumens and yolks carefully separated and weighed. The yolks of the three eggs were well mixed as were the albumens. Two 20 gm. samples of each were weighed into 125 ml. Erlenmeyer flasks, 50 ml. of 1.0 N hydrochloric acid were added, the flasks were covered with small beakers, and the contents were hydrolyzed by autoclaving for 30 minutes at 15 lb. pressure. The hydrolysates were neutralized, made to a volume of 200 ml., filtered, and the filtrate stored under
132
Downloaded from http://ps.oxfordjournals.org/ at Kokusai Hoken Keikakugaku (UNIV OF TOKYO) on May 18, 2015
(Received for publication July 19, 19S0)
133
NIACIN CONTENT OF EGGS
toluene in the refrigerator until ready for assay. Niacin assays were made microbiologically using Lactobacillus arabinosus 17-5 as the organism and the medium and procedure of KrehL Strong and Elvehjem (1943). RESULTS AND DISCUSSION
TABLE
1.-
Hen
i the niacin content of during storage of shell eggs (jug. per egg) 3 month 7 month .12 month old old old eggs eggs eggs
No.
Fresh eggs
4184 4185 4187 4188 4189* 4190 4191 4192 4193 4194*
29.9 30.2 34.9 31.9 (29.4) 33.7 31.2 31.1 27.2 (37.6)
29.1 26.5 29.5 28.3 (21.9) 31.5 29.6 28.3 28.3 (37.6)
25.1 24.5 28.4 24.9 (24.8) 27.0 26.5 25.9 24.4 (31.0)
29.5 32.8 33.6 30.0 (57.7) 33.4 36.4 30.4 31.0
Ave.*
31.3
28.9
25.8
32.1
—
* Values for hens No. 4189 and 4194 were not included in the average values, because the 12month old eggs from hen No. 4189 were slightly moldy, and no usuable 12-month old eggs were obtained for hen No. 4194. TABLE 2.—Changes in the niacin content of egg albumen during storage of shell eggs (jug. per albumen) Hen
3 month 7 month 12 month old. old old eggs eggs eggs
No.
Fresh eggs
4184 4185 4187 4188 4189* 4190 4191 4192 4193 4194*
27.5 27.2 32.1 29.0 (26.8) 31.2 28.4 28.2 24.4 (34.7)
25.9 22.7 26.3 25.1 (19.4) 27.9 26.4 24.7 24.8 (33.9)
21.5 20.4 24.7 20.9 (20.7) 22.7 22.9 20.8 20.4 (26.5)
22.8 25.3 27.2 19.0 (35.3) 22.4 24.9 22.5 16.0
Ave.*
28.5
25.5
21.8
22.5
* See footnote Table 1.
—
Hen No. 4184 4185 4187 4188 4189* 4190 4191 4192 4193 4194* Ave.*
Fresh eggs
3 month 7 month 12 month old old old eggs eggs eggs
2.4 3.0 2.8 2.9
3.2 3.8 3.2 3.2
3.6 4.1 3.7 4.0
(2.6)
(2.5)
(4.1)
2.5 2.8 2.9 2.8
3.6 3.2 3.6 3.5
4.3 3.6 5.1 4.0
(2.9)
(3.7)
(4.5)
2.8
3.4
4.1
6.7 7.5 6.4 11.0 (22.4) 11.0 11.5
7.9 15.0 —
•
9.6
* See footnote Table 1. TABLE 4.—Changes in the niacin content of albumen during storage of shell eggs (Mg. per gm.) 3 month 7 month 12 month old old old eggs eggs eggs
Hen No.
Fresh eggs
4184 4185 4187 • 4188 4189* 4190 4191 4192 4193 4194*
0.94 0.91 0.91 0.98 (0.90) 0.93 0.89 0.98 0.87 (0.93)
0.86 0.78 0.78 0.82 (0.69) 0.85 0.84 0.86 0.87 (0.91)
0.74 0.71 0.74 0.74 (0.71) 0.73 0.74 0.79 0.73 (0.80)
0.83 0.88 0.83 0.80 (1-47) 0.79 1.01 0.86 0.81
Ave.*
0.93
0.83
0.74
0.85
—
* See footnote Table 1.
jug. were in the yolk (Table 3). These values are much lower than the 56 to 64 ng. of niacin per albumen and the 17 to 21 ng. per yolk obtained by Dann and Handler (1941) using a chemical method of assay. However, the average values of 0.93 Mg- per gm. of albumen, 0.16 ng. per gm. of yolk, and 0.66 ng. per gm. of whole egg given in Tables 4, 5, and 6 for fresh eggs agree better with the literature values obtained by the microbiological assay procedure. The values for fresh whole eggs presented in Table 6 are all slightly lower
Downloaded from http://ps.oxfordjournals.org/ at Kokusai Hoken Keikakugaku (UNIV OF TOKYO) on May 18, 2015
Fresh eggs contained an average of 31.3 Mg- of niacin per egg (Table 1); 28.5 fig. were in the albumen (Table 2), and 2.8
TABLE 3.—Changes in the niacin content of egg yolk during storage of shell eggs (jtg. per yolk)
134
ROBERT JOHN EVANS, HELEN A. BUTTS AND J. A.
than the 0.72 fig. per gm. reported by Cheldelin and Williams (1942) or the 0.73 to 0.90 tig. obtained by Snell and Quarles (1941). Teply et al. (1942) found less niacin in the albumen (0.72 fig. per gm.
3 month 7 month 12 month old old old eggs eggs eggs
Hen No.
Fresh eggs
4184 4185 4187 4188 4189* 4190 4191 4192 4193 4194*
0.15 0.15 0.16 0.17 (0.14) 0.16 0.17 0.18 0.17 (0.14)
0.19 0.19 0.17 0.19 (0.14) 0.20 0.19 0.22 0.19 (0.18)
0.22 0.19 0.19 0.23 (0.21) 0.23 0.21 0.29 0.22 (0.23)
0.39 0.34 0.32 0.50 (0.93) 0.49 0.52 0.42 0.59
Ave.*
0.16
0.19
0.22
0.45
loss of niacin from the albumen was 24 percent, a decrease of 6.7 fig. per egg (Table 2). Part of the loss from the albumen was due to the transfer of 1.3 fig., of niacin to the yolk (Table 3). The loss of niacin was accompanied by a decrease of the niacin concentration in the albumen from 0.93 fig. per gm. to 0.74 fig. per gm. (Table 4). The niacin concentration in the yolk increased from 0.16 fig. per gm. to 0.22 fig. per gm. (Table 5). The above results are of interest because Evans and Davidson (1951) observed an 8.3 percent increase m yolk weight and a 7.4 percent decrease in albumen weight during seven months of cold storage. The transfer of water from the albumen to the yolk is accompanied by a transfer of niacin.
—
The niacin values for the eggs of hens No. 4189 and No. 4194 are not included in the average values give in the tables. * See footnote Table 1. Eggs from hen No. 4189 that had been TABLE 6.—Changes in the niacin content of whole eggstored for twelve months contained some during storage of shell eggs mold growth. The mold apparently synG*g. per g m.) thesized some niacin, because the twelve month old eggs contained 57.7 jug. of 3 month 7 month 12 month Hen Fresh old old old niacin compared to the 29.4 fig. in the eggs No. eggs eggs eggs fresh eggs. Recent work (Rosen et al., 0.62 0.55 0.66 4184 0.66 1946) has indicated tryptophan as a pre0.61 0.53 0.49 0.65 4185 cursor for the biological synthesis of 0.54 4187 0.66 0.56 0.63 0.60 0.55 4188 0.70 0.65 niacin. Although the niacin content of eggs (0.48) (0.51) (1.20) 4189* (0.61) is low, fresh eggs contain 65 to 74 mg. of 4190 0.68 0.62 0.55 0.66 0.55 4191 0.65 0.61 0.77 tryptophan per egg (Evans et al., 1949) 0.63 4192 0.70 0.59 0.68 which should be an abundant source from 0.53 4193 0.60 0.69 0.61 4194* (0.67) (0.66) (0.59) — which molds could synthesize niacin. None of the twelve month old eggs of hen 0.54 0.66 0.60 0.67 Ave.* No. 4194 were usable; all had to be dis* See footnote Table 1. carded as spoiled, because the yolks and compared to 0.93 fig. reported in Table 4) albumens were mixed together. Many of and more in the yolk (0.35 ng. per gm. the other twelve month old eggs had to be compared to 0.16 ng. reported in Table 5) discarded because of spoilage. As a result the values for the twelve month old eggs than we did. During the first seven months of cold of four hens were based on two eggs, and storage an 18 percent average loss of only one egg was available for hen No. niacin from the whole egg occurred, the 4188. average values decreasing from 31.3 to 25.8 fig. per egg (Table 1). The average
The temperature regulator of the walkin refrigerator did not work satisfactorily
Downloaded from http://ps.oxfordjournals.org/ at Kokusai Hoken Keikakugaku (UNIV OF TOKYO) on May 18, 2015
TABLE 5.—Changes in the niacin content of egg yolk during storage of shell eggs Og- per gm.)
DAVIDSON
135
NIACIN CONTENT OF EGGS
The data indicate that during cold storage there is a gradual loss of niacin from the shell egg. The niacin loss is of little importance in nutrition, because eggs supply a negligible amount of the dietary requirement for niacin. Contrasted to the loss of niacin from shell eggs stored in the cold is the increased niacin content of incubated fertile eggs (Dann and Handler, 1941; Snell and Quarles, 1941) and the increased niacin content of eggs stored under conditions favorable for microbial infection such as was observed in the twelve-month old eggs. SUMMARY
Fresh shell eggs contained on the average 31.3 fig. of niacin per egg or 0.66 ng. per gm. Most of the niacin (28.5 jug. or 0.93 fig. per gm.) was in the albumen, and only 2.8 fig. (0.16 fig. per gm.) was in the yolk. An average loss of 5.5 fig. of niacin occurred during seven months of cold storage. Despite a loss of water from the eggs the niacin concentration also decreased to 0.54 fig. per gm. The average
niacin content of the yolks of seven month old eggs was 4.1 fig. with a concentration of 0.22 fig. per gm. of yolk and that of the albumen was 21.8 fig. (0.74 fig. per gm.). REFERENCES Briggs, G. M., Jr., T. D. Luckey, L. J. Teply, C. A. Elvehjem and E. B. Hart, 1943. Studies on nicotinic acid deficiency in the chick. J. Biol. Chem. 148: 517-522. Briggs, G. M., Jr., R. C. Mills, C. A. Elvehjem and E. B. Hart, 1942. Nicotinic acid in chick nutrition. Proc. Soc. Exptl. Biol. Med. 51: 59-61. Cheldelin, V. H., and R. J. Williams, 1942. The B vitamin content of foods. Univ. Texas Pub. 4237: 105-124. Dann, W. J., and P. Handler, 1941. Synthesis of nicotinic acid by the chick embryo. J. Biol. Chem. 140: 935-936. Elvehjem, C. A., R. J. Madden, F. M. Strong and D. W. Woolley, 1937. Relation of nicotinic acid and nicotinic acid amide to canine black tongue. J. Am. Chem. Soc. 59: 1767-1768. Evans, R. J., and J. A. Davidson, 1951. The choline content of fresh and stored shell eggs. Poultry Sci. 30: 29-33. Evans, R. J., J. A. Davidson, S. L. Bandemer and H. A. Butts, 1949. The amino acid content of fresh and stored shell eggs. II. Arginine, histidine, lysine, methionine, cystine, tyrosine, tryptophan, phenylalanine, and proline. Poultry Sci. 28: 697-702. Evans, R. J., J. A. Davidson and H. A. Butts, 1949. Changes in egg proteins occurring during cold storage of shell eggs. Poultry Sci. 28: 206-214. Fouts, P. J., O. M. Helmer, S. Lepkovsky and T. H. Jukes, 1937. Treatment of human pellagra with nicotinic acid. Proc. Soc. Exptl. Biol. Med. 37: 405^07. Gortner, R. A., 1949. Outlines of Biochemistry, Third Edition, New York. John Wiley and Sons, Inc. Krehl, W. A., F . M. Strong and C. A. Elvehjem, 1943. Determination of nicotinic acid. Modifications in the microbiological method. Ind. Eng. Chem., Anal. Ed. 15:471-475. Rosen, F., J. W. Huff and W. A. Perlzweig, 1946. The effect of tryptophan on the synthesis of nicotinic acid in the rat. J. Biol. Chem. 163: 343-344. Snell, E. E., and E. Quarles, 1941. The effect of incubation on the vitamin content of eggs. J. Nutrition 22: 483-489. Teply, L. J., F. M. Strong and C. A. Elvehjem, 1942. The distribution of nicotinic acid in foods. J. Nutrition 23: 417-423.
Downloaded from http://ps.oxfordjournals.org/ at Kokusai Hoken Keikakugaku (UNIV OF TOKYO) on May 18, 2015
for a period between the time that the seven and the twelve month old eggs were taken out of storage. The temperature at one time went low enough to freeze and crack many of the eggs, and then it went high enough to start mold growth. Many eggs deteriorated to such an extent that the vitelline membrane ruptured before or during the boiling of the egg, and the albumen and yolk were mixed together so that the eggs could not be used. Even the eggs that were not cracked or that did not have ruptured membranes were probably affected by the adverse temperatures. Because of these conditions it is felt that the data from the twelve-month old eggs can not be considered as typical of what occurs during the proper cold storage of shell eggs. The rise in niacin content of the twelve month old eggs was probably caused by microbiological synthesis.