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Fat Rancidity in Eviscerated Poultry1
Fat Rancidity in Eviscerated Poultry1 III. THE EFFECT OF VARIATIONS IN DIETARY FAT, ETHANOLAMINE AND CHOLINE ON THE STORAGE QUALITY OF MATURE TURKEYS 2 J. P. H I T E , S. E. KLOXIN, F. A. KUMMEROW, G. E. VAIL AND T. B. AVERY
• Kansas Agricultural Experiment Station,3 Manhattan, Kansas (Received for publication August 25, 1948)
1
The subject matter of this paper has been undertaken in cooperation with the Committee on Food Research of the Quartermaster Food and Container Institute for the Armed Forces. The opinions or conclusions contained in this report are those of the authors. They are not to be construed as necessarily reflecting the views or indorsement of the War Department. 2 Portion of a thesis presented by Jean Peck Hite as partial fulfillment, of the requirements for the degree of Master of Science in Foods and Nutrition at Kansas State College, 1948. 3 Contribution No. 365 from the Department of Chemistry, No. 177 from the Department of Poultry Husbandry, and No. 144 from the School of Home Economics.
1942) did not increase the stability of depot fat. Recent studies (Kummerow et al. 1948) have indicated that the stability of fat extracted from the skin of immature turkeys could be influenced by various dietary factors. In the present work an attempt was made to test the influence of these factors on the stability of fat in mature turkeys. EXPERIMENTAL One hundred and seventy five day-old bronze poults were started on the two basal rations shown in Tables I and II. One hundred and twenty five poults were fed ration #1, the remaining 50 were fed ration #2. Basal ration #1 contained 2.6% and ration #2, 3.9% of ether extractable material. Spectrophotometric analyses indicated that the lipids extracted from basal ration #1 contained 0.1% and those from #2 contained 2.1%) linolenic acid. Neither ration contained arachidonic acid. After eight weeks, the 125 poults on ration #1 were divided into nine groups and fed different supplements (Table III). The supplements of ethanolamine, hydrogenated fat,4 raw linseed oil or alfalfa leaf meal were mixed directly with the basal ration. The addition of 2% hydrogenated fat or 10% alfalfa leaf meal decreased and that of linseed oil meal increased the i Furnished through the courtesy of Dr. Stuart W. Thompson, Lever Bros. Co., Cambridge, Mass.
244
Downloaded from http://ps.oxfordjournals.org/ at Georgetown University on May 25, 2015
ACCORDING to Barnes et al. (1943), -**• there are two basic factors of importance governing the resistance of-natural fats to rancidification. These are 1), the composition of the component glycerides and 2), the amount and nature of existing natural antioxidants. Studies on the composition of the component glycerides of poultry fat (Cruickshank, 1934 and Hilditch et al. 1934) have shown that the composition depended on the nature of the dietary fat. Cruickshank, for example, has shown that the feeding of hempseed produced a marked and rapid increase in unsaturation of the mixed fatty acids of the depot fats in poultry. Furthermore, the feeding of alfalfa or fish oils (Schreiber et al. 1947) decreased the storage life of frozen poultry. On the other hand, the feeding of antioxidants (Barnes et al. 1943 and Overman,
FAT RANCIDITY IN EVISCERATED POULTRY TABLE I.—Basal ration §1 Ingredients
Pounds
1 Courtesy of Distillation Products, Rochester, N. Y. 2 Courtesy of E. I. Du Pont de Nemours & Co., Wilmington, Dela. 3 Courtesy of Lederle, Inc., Pearl River, N. Y.
TABLE II.—Basal rations §2 Ingredients
Pounds
Yellow corn 20.0 Ground wheat 10.0 Ground oats 10.0 Wheat shorts 10.0 Wheat bran 5.0 Alfalfa leaf meal 7.0 Meat and bone scraps 20.0 Soybean meal 15.0 Ground limestone 2.0 Sodium chloride 1.0 150 g. Prot-A, 50 g. D -sec,, 3 g. riboflavin mix, 15 g. manganese sulfate, wheat, corn and grass range ad libitum.
iodine value of the lipids which could be extracted from the ration. The lipids extracted from the basal ration had an iodine value of 113.4, the hydrogenated fat 86.7, alfalfa leaf meal 103.6 and linseed oil 128.2. The ethanolamine was neutralized with hydrochloric acid and both the choline and ethanolamine hydrochloride were diluted with water before they were mixed with the ration. The birds were kept in a converted brooder house and the groups separated by a wire enclosure. A fenced graveled runway outside each enclosure permitted ready access to sunlight and fresh air.
The 50 poults on ration #2 were divided into three groups. A control group was fed the basal ration, the ration of a second group was supplemented with choline and the third received a supplement of ethanolamine. The birds were allowed to run in a wire-enclosed grass range, simulating the usual farm practice. All of the birds were weighed at 8, 12 and 16 weeks of age. Turkeys in groups 1 to 9, which had received ration #1, were killed at 22 weeks and groups 10 to 12, which had received ration §2, were killed at 28 weeks of age. The birds were dressed under standardized conditions as previously described by Wagoner et al. (1947). Five birds from each group were wrapped in MSAT cellophane,5 sealed with Scotch tape and placed in cold storage at — 13°C. At least one turkey from each group was analyzed after 4, 9 and 12 months of storage. The skin from the breast and one leg was removed and the fat extracted from the skin with ethylene chloride. Acid, peroxide and aldehyde values were determined as described by Schreiber et al. (1947). One unskinned leg from each turkey was used for organoleptic tests. The leg was thawed, cleaned and cooked according to the method of Vail and Conrad (1948). As in previous studies (Kummerow et al. 1948) a score of 10 was considered the maximum possible score, a score of 5.0 indicated that the bird was barely acceptable and a score of 3.0 indicated that the meat was definitely unacceptable. RESULTS
The birds which had been kept on basal ration #2 and those which had received basal ration #1 supplemented with 10% alfalfa leaf meal weighed approximately the same at 16 weeks of age. Those supples
Courtesy of E. I. du Pont de Nemours & Co., Wilmington, Dela.
Downloaded from http://ps.oxfordjournals.org/ at Georgetown University on May 25, 2015
Skim milk powder 15.0 Dried brewers' yeast 3.0 Corn gluten meal 12.0 Corn oil cake 12.0 Ground corn or sorghum 23.0 Gelatin 2.0 Soybean meal (solvent extracted) 5.0 Ground oats 20.0 Limestone 2.0 Sodium chloride 0.9 Dicalcium phosphate 3.5 3.5 mg. vitamin A cone.,1 0.6 g. tocopherol cone., 1 1.6 mg. crystalline vitamin D, 2 0.25 g. folic acid,3 0.06 g. pyridoxine, 1 g. niacin, 50 g. choline, 10 g. manganese sulfate.
245
246
J. P. H I T E , S. E. KLOXIN, F. A. KUMMEROW, G. E. VAIL, T. B. AVERY
gains of turkeys TABLE III.—Diet variations and weight Average weight of birds in pounds at: 16 wks. 22 wks. 8wks.
Fat supplement per 100 lbs. feed
1 2 3 4 5 6 7 8 9
To Basal Ration #1 none none+100 g. etha.* 2% hydro, fat 2% hydro, fat+100 g. etha. 10% alfalfa meal 10% alfalfa meal+100 g. etha. 1% raw linseed oil 1% raw linseed oil+100 g. etha. 1% raw linseed oil+100 g. etha. and 50 g. choline
1.3 1.3 1.4 1.5 1.3 1.3 1.2 1.2 1.5
9.9 8.8 9.7 9.5 7.7 7.3 9.1 10.0 8.9
16.2 14.8 12.3 14.4 12.8 14.4 15.2 15.0 14.1
To Basal Ration §2
8wks.
16 wks.
28 wks.
1.6 1.5 1.6
7.1 7.2 7.3
17.8 17.6 17.3
10 11 12
none none+50 g. choline chloride none+100 g. etha.
etha.—ethanolamine, tech. grade, neutralized with hydrochloric acid.
groups which had been supplemented with ethanolamine were still acceptable. After 12 months of storage, only those birds which had received basal ration fl and this ration plus choline were considered edible by the palatability committee. The groups which had received basal ration f\ plus linseed oil, either alone or with ethanolamine or choline, were considered to have the most pronounced oxidized flavors. The characteristics of the fat extracted from the skin of the stored turkeys indicated that the birds which had received ethanolamine deposited fat which was more stable than that of the unsupple-
mented with linseed oil or hydrogenated fat weighed from one to two pounds more than the birds which had been supplemented with alfalfa leaf meal. However, at 22 weeks these differences were no longer apparent. The group killed at 22 weeks of age weighed from 12 to 16 pounds and those killed at 28 weeks weighed from 2 to 3 pounds more. Organoleptic tests indicated that after four months of storage all groups of turkeys were acceptable (Table IV). At nine months, the groups which had received linseed oil and hydrogenated fat but no supplements of ethanolamine or choline were unacceptable. However, similar
TABLE IV.—The effect offeeding ethanolamine on the organoleptic rating and acid values of stored turkeys Acid values after
Organoleptic ratings after Supplement to basal ration
4 months
9 months
12 months
4 months
9 months
12 months
None
Etha.«
None
Etha.
None
Etha.
None
Etha.
None
Etha.
None
Etha.
none hydro, fat alfalfa meal linseed oil " " -j-choline
6.1 5.6 6.6 7.4
6.2 5.1 7.1 5.9 6.9
5.8 3.7 4.6 3.4
5.8 4.1 4.8 4.4 5.4
3.8 4.2 4.2 2.6
4.0 3.8 3.5 1.8 3.0
1.1 2.5 0.9 2.0
1.4 1.4 1.4 1.3 1.2
1.0 5.7 1.2 2.0
1.2 2.1 2.1 1.3 2.2
2.5 3.3 1.5 1.9
2.1 4.2 1.9 2.2 2.6
Ration #2 none choline only
8.0 7.1
8.1
6.9 5.4
7.2
3.0 5.8
5.3
0.6 0.8
0.5
1.1 0.7
0.8
1.1 0.8
1.3
Ration #1
* Ethanolamine.
Downloaded from http://ps.oxfordjournals.org/ at Georgetown University on May 25, 2015
Group
FAT RANCIDITY IN EVISCERATED POULTRY
247
TABLE V.—The effect offeeding ethanolamine on the peroxide and aldehyde values offat extracted from stored turkeys Aldehyde values
Peroxide values Supplement to basal ration
*
4 months
12 months
9 months
4 months
9 months
.12 months
None
Etha.*
None
Etha.
None
Etha.
None
Etha.
None
Etha.
None
Etha.
Basal Ration #1 none hydro, fat alfalfa meal linseed oil lins. oil, choline
4.8 2.1 12.5 31.1
3.9 3.7 15.8 14.1 15.4
31.1 11.2 22.5 42.6
27.7 12.8 18.5 31.8 28.0
42.0 12.0 37.9 46.5
29.5 17.5 23.1 47.6 28.1
7.2 9.2 10.3 916
8.9 8.7 10.1 8.3 8.2
28.2 24.0 46.2 50.2
29.6 23.9 31.5 40.7 39.0
190 62 250 175
226 113 76 223 89
Basal Ration #2 none choline only
6.3 8.2
2.6
9.5 7.2
5.8
26.8 22.3
11.8
8.7 8.9
4.3
14.1 13.9
5 .9
144 59
160
mented turkeys. In almost every case, the peroxide and aldehyde values of the fat extracted from the supplemented groups were lower than the values of the fat extracted from the unsupplemented groups. These differences were greatest after four and nine months of storage in groups which had been fed linseed oil. Ethanolamine and choline were also effective when fed to birds kept on a typical turkey ration, i.e., basal ration §2, and grain and grass range similar to actual commercial practice. DISCUSSION
The data obtained in this study seemed to indicate that ethanolamine had a stabilizing effect on the carcass fat of mature turkeys during cold storage. Furthermore, the addition of ethanolamine to the ration was especially beneficial if the carcasses were not stored more than nine months. In a previous study with immature turkeys, which were killed at 12 weeks of age, (Kummerow et al. 1948) the feeding of ethanolamine had increased the stability of the skin fat, although this increase was not apparent after nine months of cold storage. In the present studies the peroxide values of the fat extracted from the skin after 12 months of storage indicated that ethanolamine still had a stabilizing effect. However, the threshold of acceptability had been passed and except for the
groups on ration #2 those effects were no longer reflected in the organoleptic ratings. It is also interesting to note the organoleptic tests indicated that the threshold of acceptability was higher with mature birds. In previous work with immature birds a peroxide value of 10 and an aldehyde value of 25 seemed to determine the threshold. In the present study, carcasses which had a peroxide value as high as 31 and an aldehyde value as high as 160 were still graded as acceptable by the tasting panel. The presence of heptaldehydes has been suggested to be responsible for the rancid odor of fats (Powick, 1923). If the linolenic acid in linseed oil were deposited in the skin tissue in substantial amounts it would be a potential source of heptaldehydes. Actually, the peroxide value of the group which had been supplemented with linseed oil increased most rapidly. However, the feeding of hydrogenated fat, which was completely free of linolenic acid, did not improve the organoleptic characteristics of the fat either. White (1941) has stated that the precision of the aldehyde determination is poor, but that it did possess the advantage of measuring some of the breakdown products directly responsible for the rancid odor and flavor. In the present work it was found that the extraction pro-
Downloaded from http://ps.oxfordjournals.org/ at Georgetown University on May 25, 2015
* Ethanolamine.
248
J. P. H I T E , S. E. KLOXIN, F. A. KUMMEROW, G. E. VAIL, T. B. AVEKY
cedure must be standardized in order to obtain reproducible aldehyde values. This was most essential during the extraction of skin tissue obtained from carcasses which had been stored for long periods of time. Some destruction of aldehydes was noticed in these cases and therefore extraction with cold ethylene chloride or chloroform may be a better procedure than extraction with hot ethylene chloride as recommended by Wagoner et al. (1947).
The keeping qualities of eviscerated turkeys were compared after 4, 9 and 12 months of cold storage. These turkeys had been kept on two different basal rations, and had received various supplements of choline, ethanolamine or fat. One basal
Book Reviews {Continued from page 239)
research, teaching and advanced students, it would seem highly desirable to have two books covering this subject. By this means, one book could thoroughly review the research work in processing and food technology related to poultry products. Another might emphasize the "machinery" of distribution and economics of marketing methods. Each of these major divisions of the poultry marketing industry should welcome a comprehensive treatise and study completely annotated with literature references. ROMANOFF, ALEXIS L. AND ANASTASIA J. ROMANOFF. The Avian Egg. John Wiley
& Sons, New York, 1949. 918 pages. Price $14.00. The Romanoffs have prepared a book which "represents an attempt to compile all known facts about the bird's egg." They have divided the subject matter
into three parts: (1) the development and peculiarities of form and structure; (2) chemical, physical and biological properties; and (3) food value, preservation and industrial uses of the egg and its parts. An author and journal reference list of 64 pages is included. The book appears to be a worthwhile reference for anyone wishing to secure information on eggs. A majority of the statements are indexed to the references. Any book of this magnitude must of necessity, reflect the opinions and expressions of the authors. The style of writing is clear and concise, making the subject matter very readable. The text is liberally interspersed with diagrammatic drawings by the senior author. The Romanoffs are to be commended for their efforts in gathering together so much data in a treatise of wide and varying subject matter.
Downloaded from http://ps.oxfordjournals.org/ at Georgetown University on May 25, 2015
SUMMARY
ration was an experimental ration and the other a typical turkey ration. The acid, peroxide and aldehyde values of the fat extracted from the skins and the organoleptic tests of the unskinned carcass cooked under standardized conditions were used as a criterion for judging the keeping quality of the birds. These tests indicated that after four months of storage all the birds were acceptable. After nine months of storage all birds except those which had received supplements of 2% hydrogenated fat, 10% alfalfa leaf meal or 1% linseed oil were still acceptable, and after twelve months of storage, only those which had received the typical turkey ration plus ethanolamine or choline were still acceptable.
• Kansas Agricultural Experiment Station,3 Manhattan, Kansas (Received for publication August 25, 1948)
1
The subject matter of this paper has been undertaken in cooperation with the Committee on Food Research of the Quartermaster Food and Container Institute for the Armed Forces. The opinions or conclusions contained in this report are those of the authors. They are not to be construed as necessarily reflecting the views or indorsement of the War Department. 2 Portion of a thesis presented by Jean Peck Hite as partial fulfillment, of the requirements for the degree of Master of Science in Foods and Nutrition at Kansas State College, 1948. 3 Contribution No. 365 from the Department of Chemistry, No. 177 from the Department of Poultry Husbandry, and No. 144 from the School of Home Economics.
1942) did not increase the stability of depot fat. Recent studies (Kummerow et al. 1948) have indicated that the stability of fat extracted from the skin of immature turkeys could be influenced by various dietary factors. In the present work an attempt was made to test the influence of these factors on the stability of fat in mature turkeys. EXPERIMENTAL One hundred and seventy five day-old bronze poults were started on the two basal rations shown in Tables I and II. One hundred and twenty five poults were fed ration #1, the remaining 50 were fed ration #2. Basal ration #1 contained 2.6% and ration #2, 3.9% of ether extractable material. Spectrophotometric analyses indicated that the lipids extracted from basal ration #1 contained 0.1% and those from #2 contained 2.1%) linolenic acid. Neither ration contained arachidonic acid. After eight weeks, the 125 poults on ration #1 were divided into nine groups and fed different supplements (Table III). The supplements of ethanolamine, hydrogenated fat,4 raw linseed oil or alfalfa leaf meal were mixed directly with the basal ration. The addition of 2% hydrogenated fat or 10% alfalfa leaf meal decreased and that of linseed oil meal increased the i Furnished through the courtesy of Dr. Stuart W. Thompson, Lever Bros. Co., Cambridge, Mass.
244
Downloaded from http://ps.oxfordjournals.org/ at Georgetown University on May 25, 2015
ACCORDING to Barnes et al. (1943), -**• there are two basic factors of importance governing the resistance of-natural fats to rancidification. These are 1), the composition of the component glycerides and 2), the amount and nature of existing natural antioxidants. Studies on the composition of the component glycerides of poultry fat (Cruickshank, 1934 and Hilditch et al. 1934) have shown that the composition depended on the nature of the dietary fat. Cruickshank, for example, has shown that the feeding of hempseed produced a marked and rapid increase in unsaturation of the mixed fatty acids of the depot fats in poultry. Furthermore, the feeding of alfalfa or fish oils (Schreiber et al. 1947) decreased the storage life of frozen poultry. On the other hand, the feeding of antioxidants (Barnes et al. 1943 and Overman,
FAT RANCIDITY IN EVISCERATED POULTRY TABLE I.—Basal ration §1 Ingredients
Pounds
1 Courtesy of Distillation Products, Rochester, N. Y. 2 Courtesy of E. I. Du Pont de Nemours & Co., Wilmington, Dela. 3 Courtesy of Lederle, Inc., Pearl River, N. Y.
TABLE II.—Basal rations §2 Ingredients
Pounds
Yellow corn 20.0 Ground wheat 10.0 Ground oats 10.0 Wheat shorts 10.0 Wheat bran 5.0 Alfalfa leaf meal 7.0 Meat and bone scraps 20.0 Soybean meal 15.0 Ground limestone 2.0 Sodium chloride 1.0 150 g. Prot-A, 50 g. D -sec,, 3 g. riboflavin mix, 15 g. manganese sulfate, wheat, corn and grass range ad libitum.
iodine value of the lipids which could be extracted from the ration. The lipids extracted from the basal ration had an iodine value of 113.4, the hydrogenated fat 86.7, alfalfa leaf meal 103.6 and linseed oil 128.2. The ethanolamine was neutralized with hydrochloric acid and both the choline and ethanolamine hydrochloride were diluted with water before they were mixed with the ration. The birds were kept in a converted brooder house and the groups separated by a wire enclosure. A fenced graveled runway outside each enclosure permitted ready access to sunlight and fresh air.
The 50 poults on ration #2 were divided into three groups. A control group was fed the basal ration, the ration of a second group was supplemented with choline and the third received a supplement of ethanolamine. The birds were allowed to run in a wire-enclosed grass range, simulating the usual farm practice. All of the birds were weighed at 8, 12 and 16 weeks of age. Turkeys in groups 1 to 9, which had received ration #1, were killed at 22 weeks and groups 10 to 12, which had received ration §2, were killed at 28 weeks of age. The birds were dressed under standardized conditions as previously described by Wagoner et al. (1947). Five birds from each group were wrapped in MSAT cellophane,5 sealed with Scotch tape and placed in cold storage at — 13°C. At least one turkey from each group was analyzed after 4, 9 and 12 months of storage. The skin from the breast and one leg was removed and the fat extracted from the skin with ethylene chloride. Acid, peroxide and aldehyde values were determined as described by Schreiber et al. (1947). One unskinned leg from each turkey was used for organoleptic tests. The leg was thawed, cleaned and cooked according to the method of Vail and Conrad (1948). As in previous studies (Kummerow et al. 1948) a score of 10 was considered the maximum possible score, a score of 5.0 indicated that the bird was barely acceptable and a score of 3.0 indicated that the meat was definitely unacceptable. RESULTS
The birds which had been kept on basal ration #2 and those which had received basal ration #1 supplemented with 10% alfalfa leaf meal weighed approximately the same at 16 weeks of age. Those supples
Courtesy of E. I. du Pont de Nemours & Co., Wilmington, Dela.
Downloaded from http://ps.oxfordjournals.org/ at Georgetown University on May 25, 2015
Skim milk powder 15.0 Dried brewers' yeast 3.0 Corn gluten meal 12.0 Corn oil cake 12.0 Ground corn or sorghum 23.0 Gelatin 2.0 Soybean meal (solvent extracted) 5.0 Ground oats 20.0 Limestone 2.0 Sodium chloride 0.9 Dicalcium phosphate 3.5 3.5 mg. vitamin A cone.,1 0.6 g. tocopherol cone., 1 1.6 mg. crystalline vitamin D, 2 0.25 g. folic acid,3 0.06 g. pyridoxine, 1 g. niacin, 50 g. choline, 10 g. manganese sulfate.
245
246
J. P. H I T E , S. E. KLOXIN, F. A. KUMMEROW, G. E. VAIL, T. B. AVERY
gains of turkeys TABLE III.—Diet variations and weight Average weight of birds in pounds at: 16 wks. 22 wks. 8wks.
Fat supplement per 100 lbs. feed
1 2 3 4 5 6 7 8 9
To Basal Ration #1 none none+100 g. etha.* 2% hydro, fat 2% hydro, fat+100 g. etha. 10% alfalfa meal 10% alfalfa meal+100 g. etha. 1% raw linseed oil 1% raw linseed oil+100 g. etha. 1% raw linseed oil+100 g. etha. and 50 g. choline
1.3 1.3 1.4 1.5 1.3 1.3 1.2 1.2 1.5
9.9 8.8 9.7 9.5 7.7 7.3 9.1 10.0 8.9
16.2 14.8 12.3 14.4 12.8 14.4 15.2 15.0 14.1
To Basal Ration §2
8wks.
16 wks.
28 wks.
1.6 1.5 1.6
7.1 7.2 7.3
17.8 17.6 17.3
10 11 12
none none+50 g. choline chloride none+100 g. etha.
etha.—ethanolamine, tech. grade, neutralized with hydrochloric acid.
groups which had been supplemented with ethanolamine were still acceptable. After 12 months of storage, only those birds which had received basal ration fl and this ration plus choline were considered edible by the palatability committee. The groups which had received basal ration f\ plus linseed oil, either alone or with ethanolamine or choline, were considered to have the most pronounced oxidized flavors. The characteristics of the fat extracted from the skin of the stored turkeys indicated that the birds which had received ethanolamine deposited fat which was more stable than that of the unsupple-
mented with linseed oil or hydrogenated fat weighed from one to two pounds more than the birds which had been supplemented with alfalfa leaf meal. However, at 22 weeks these differences were no longer apparent. The group killed at 22 weeks of age weighed from 12 to 16 pounds and those killed at 28 weeks weighed from 2 to 3 pounds more. Organoleptic tests indicated that after four months of storage all groups of turkeys were acceptable (Table IV). At nine months, the groups which had received linseed oil and hydrogenated fat but no supplements of ethanolamine or choline were unacceptable. However, similar
TABLE IV.—The effect offeeding ethanolamine on the organoleptic rating and acid values of stored turkeys Acid values after
Organoleptic ratings after Supplement to basal ration
4 months
9 months
12 months
4 months
9 months
12 months
None
Etha.«
None
Etha.
None
Etha.
None
Etha.
None
Etha.
None
Etha.
none hydro, fat alfalfa meal linseed oil " " -j-choline
6.1 5.6 6.6 7.4
6.2 5.1 7.1 5.9 6.9
5.8 3.7 4.6 3.4
5.8 4.1 4.8 4.4 5.4
3.8 4.2 4.2 2.6
4.0 3.8 3.5 1.8 3.0
1.1 2.5 0.9 2.0
1.4 1.4 1.4 1.3 1.2
1.0 5.7 1.2 2.0
1.2 2.1 2.1 1.3 2.2
2.5 3.3 1.5 1.9
2.1 4.2 1.9 2.2 2.6
Ration #2 none choline only
8.0 7.1
8.1
6.9 5.4
7.2
3.0 5.8
5.3
0.6 0.8
0.5
1.1 0.7
0.8
1.1 0.8
1.3
Ration #1
* Ethanolamine.
Downloaded from http://ps.oxfordjournals.org/ at Georgetown University on May 25, 2015
Group
FAT RANCIDITY IN EVISCERATED POULTRY
247
TABLE V.—The effect offeeding ethanolamine on the peroxide and aldehyde values offat extracted from stored turkeys Aldehyde values
Peroxide values Supplement to basal ration
*
4 months
12 months
9 months
4 months
9 months
.12 months
None
Etha.*
None
Etha.
None
Etha.
None
Etha.
None
Etha.
None
Etha.
Basal Ration #1 none hydro, fat alfalfa meal linseed oil lins. oil, choline
4.8 2.1 12.5 31.1
3.9 3.7 15.8 14.1 15.4
31.1 11.2 22.5 42.6
27.7 12.8 18.5 31.8 28.0
42.0 12.0 37.9 46.5
29.5 17.5 23.1 47.6 28.1
7.2 9.2 10.3 916
8.9 8.7 10.1 8.3 8.2
28.2 24.0 46.2 50.2
29.6 23.9 31.5 40.7 39.0
190 62 250 175
226 113 76 223 89
Basal Ration #2 none choline only
6.3 8.2
2.6
9.5 7.2
5.8
26.8 22.3
11.8
8.7 8.9
4.3
14.1 13.9
5 .9
144 59
160
mented turkeys. In almost every case, the peroxide and aldehyde values of the fat extracted from the supplemented groups were lower than the values of the fat extracted from the unsupplemented groups. These differences were greatest after four and nine months of storage in groups which had been fed linseed oil. Ethanolamine and choline were also effective when fed to birds kept on a typical turkey ration, i.e., basal ration §2, and grain and grass range similar to actual commercial practice. DISCUSSION
The data obtained in this study seemed to indicate that ethanolamine had a stabilizing effect on the carcass fat of mature turkeys during cold storage. Furthermore, the addition of ethanolamine to the ration was especially beneficial if the carcasses were not stored more than nine months. In a previous study with immature turkeys, which were killed at 12 weeks of age, (Kummerow et al. 1948) the feeding of ethanolamine had increased the stability of the skin fat, although this increase was not apparent after nine months of cold storage. In the present studies the peroxide values of the fat extracted from the skin after 12 months of storage indicated that ethanolamine still had a stabilizing effect. However, the threshold of acceptability had been passed and except for the
groups on ration #2 those effects were no longer reflected in the organoleptic ratings. It is also interesting to note the organoleptic tests indicated that the threshold of acceptability was higher with mature birds. In previous work with immature birds a peroxide value of 10 and an aldehyde value of 25 seemed to determine the threshold. In the present study, carcasses which had a peroxide value as high as 31 and an aldehyde value as high as 160 were still graded as acceptable by the tasting panel. The presence of heptaldehydes has been suggested to be responsible for the rancid odor of fats (Powick, 1923). If the linolenic acid in linseed oil were deposited in the skin tissue in substantial amounts it would be a potential source of heptaldehydes. Actually, the peroxide value of the group which had been supplemented with linseed oil increased most rapidly. However, the feeding of hydrogenated fat, which was completely free of linolenic acid, did not improve the organoleptic characteristics of the fat either. White (1941) has stated that the precision of the aldehyde determination is poor, but that it did possess the advantage of measuring some of the breakdown products directly responsible for the rancid odor and flavor. In the present work it was found that the extraction pro-
Downloaded from http://ps.oxfordjournals.org/ at Georgetown University on May 25, 2015
* Ethanolamine.
248
J. P. H I T E , S. E. KLOXIN, F. A. KUMMEROW, G. E. VAIL, T. B. AVEKY
cedure must be standardized in order to obtain reproducible aldehyde values. This was most essential during the extraction of skin tissue obtained from carcasses which had been stored for long periods of time. Some destruction of aldehydes was noticed in these cases and therefore extraction with cold ethylene chloride or chloroform may be a better procedure than extraction with hot ethylene chloride as recommended by Wagoner et al. (1947).
The keeping qualities of eviscerated turkeys were compared after 4, 9 and 12 months of cold storage. These turkeys had been kept on two different basal rations, and had received various supplements of choline, ethanolamine or fat. One basal
Book Reviews {Continued from page 239)
research, teaching and advanced students, it would seem highly desirable to have two books covering this subject. By this means, one book could thoroughly review the research work in processing and food technology related to poultry products. Another might emphasize the "machinery" of distribution and economics of marketing methods. Each of these major divisions of the poultry marketing industry should welcome a comprehensive treatise and study completely annotated with literature references. ROMANOFF, ALEXIS L. AND ANASTASIA J. ROMANOFF. The Avian Egg. John Wiley
& Sons, New York, 1949. 918 pages. Price $14.00. The Romanoffs have prepared a book which "represents an attempt to compile all known facts about the bird's egg." They have divided the subject matter
into three parts: (1) the development and peculiarities of form and structure; (2) chemical, physical and biological properties; and (3) food value, preservation and industrial uses of the egg and its parts. An author and journal reference list of 64 pages is included. The book appears to be a worthwhile reference for anyone wishing to secure information on eggs. A majority of the statements are indexed to the references. Any book of this magnitude must of necessity, reflect the opinions and expressions of the authors. The style of writing is clear and concise, making the subject matter very readable. The text is liberally interspersed with diagrammatic drawings by the senior author. The Romanoffs are to be commended for their efforts in gathering together so much data in a treatise of wide and varying subject matter.
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SUMMARY
ration was an experimental ration and the other a typical turkey ration. The acid, peroxide and aldehyde values of the fat extracted from the skins and the organoleptic tests of the unskinned carcass cooked under standardized conditions were used as a criterion for judging the keeping quality of the birds. These tests indicated that after four months of storage all the birds were acceptable. After nine months of storage all birds except those which had received supplements of 2% hydrogenated fat, 10% alfalfa leaf meal or 1% linseed oil were still acceptable, and after twelve months of storage, only those which had received the typical turkey ration plus ethanolamine or choline were still acceptable.