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The Effect of Freezing on the Amino Acid Content of Fried Chicken1
1136
RESEARCH NOTES REFERENCES
TABLE 3.—Means for various production characteristics Trait
Control
TU
Age 50% Prod, (days) Avg. Eggs/Bird Housed 40-Wk. Egg Wt. (g.) Growing Mort. (%) Laying Mort. (%) % Hatchability 1
236 38.6 86.9 15.0 14.8 54.5
241 39.2 83.7 13.8 3.7 55.0
1
Hatch of fertile eggs (36 to 41 weeks).
THE EFFECT OF FREEZING ON THE AMINO ACID CONTENT OF FRIED CHICKEN 1 JOE G. BERRY2 AND F. E. CUNNINGHAM 3 Dairy and Poultry Science Department, Kansas State University, Manhattan, Kansas 66502 (Received for publication May 16, 1970)
Ambler (1929) reported that amino acids could be destroyed through condensation with accompanying aldehydes. The reaction occurred when the medium containing the two was heated (but not boiled) and the aldehydes were not removed rap1 Contribution No. 768, Department of Dairy and Poultry Science Department, Kansas Agricultural Experiment Station, Manhattan, Kansas 66S02. "'Present Address: Department of Poultry Science, Purdue University, Lafayette, Indiana 47907. 3 Member of Faculty of Food Science.
idly. Schonberg and Moubacker (1952), in reporting on the Strecker degradation of amino acids, found that the fate of the amino acids depends upon the nature of the carbonyl compound involved. Ballance (1961) reported that degradation of methionine could be responsible for some of the volatile sulphur compounds detected in the odor of nonirradiated foods. Swanson and Sloan (1953) invested protein changes in frozen poultry and reported that freezing changed the amount of amino nitrogen. Colombo and Gervasini (1958)
Downloaded from http://ps.oxfordjournals.org/ by guest on April 7, 2015
nounced when fertility is high (Marks, 1969). Differences between TU treated and control females were small for other traits measured except laying mortality (Table 3). While the difference in laying mortality was significant (P < .05) small sample sizes may not have allowed for valid mortality estimates. The relative responses of other traits are in general agreement with comparable observations in Coturnix and chickens.
Andrews, F. N., and E. E. Schnetzler, 194S. The effect of feeding thiouracil to hens upon the thyroid gland of chicks. Endocrinology, 37: 382-384. Ershoff, B. H., 1945. Effects of thyroid feeding on ovarian development in the rat. Endocrinology, 37: 218-220. Jones, G. E. S., E. Delfs and E. C. Foote, 1946. The effect of thiouracil on reproduction in the rat. Endocrinology, 38: 337-344. Marks, H. L., 1969. Fertility of chickens fed thiouracil prior to maturity. Poultry Sci. 48: 16121618. Marks, H. L., and P. D. Lepore, 1968. The influence of selection for body weight under different environments on other quantitative traits in Japanese quail. Poultry Sci. 47 : 1691. McCartney, M. G., and C. S. Shaffner, 1950. The influence of altered metabolism upon fertility and hatchability in the female fowl. Poultry Sci. 29: 67-77. Shaffner, C. S., and F. N. Andrews, 1948. The influence of thiouracil on semen quality in the fowl. Poultry Sci. 27: 91-102. Weichert, C. K., 1930. Effect of experimental hyperthyroidism on reproductive processes in female albino rats. Physiol. Zool. 3 : 461-466.
RESEARCH NOTES TABLE 1.—Average free amino acid concentration* of fresh-fried and frozen-fried chicken Fresh-fried
Dark
Light
2.000 1.240 — 2.550 — 0.570 — 0.930 0.585 2.470 1.400 3.080 1.540 0.970 0.390 1.660 0.865 2.400 1.565 0.360 0.595 0.360 0.200 0.685 0.320 1.030 0.790 — 0.105 — 0.050
1.105 1.100 1.600 0.160 0.240 1.785 1.660 0.160 0.645 1.200 0.840 0.080 0.100 0.185
— — — —
— —
0.250 1.230 0.885 0.120 0.400 0.710 0.165 0.100 0.125 0.280 0.120 0.060
* Concentration in micromoles/1 gm. sample.
found changes in several amino acids when they compared fresh, refrigerated and frozen meat samples. Miller et al. (1965) found that, with only a few exceptions, free amino acid content of dark meat was greater than that of light meat. MATERIALS AND METHODS Meat samples were analyzed for free amino acids using the Beckman Model 120C Amino Acid Analyzer. Twenty-five grams of chopped meat, combined with 50 ml. of distilled water, were homogenized for 30 sec. in a Virtis 23 homogenizer. The samples were filtered through a layer of cheese cloth and 25 ml. of the liquid portion collected. From that sample, 20 ml. were reduced to 5 ml. in volume on a rotary evaporator. The quantity of each amino acid present was determined by the procedure outlined in Beckman's operations manual' for the analyzer. Fresh-fried and frozenfried samples were compared to determine compositional changes during storage. RESULTS AND DISCUSSION The results from the determinations of
amino acids in the frozen and fresh samples are presented in Table 1. The facilities available did not allow extensive amino acid analysis; therefore these results are from the analysis of one sample each from the frozen and the fresh-fried meat. With the exception of tyrosine and phenylalanine, all amino acids in the light meat were found to be present in greater quantities in the fresh than in the frozen meat. Without exception, the same was true for the dark meat. Differences in amounts of amino acids were more pronounced and greater amounts of free amino acids were present in the dark than in the light meat. The results generally agree with those of Miller et al. (1965). Several researchers (Ambler, 1929; Schonberg and Moubacker, 1952; Ballance, 1961) have reported on degradation of amino acids under controlled conditions that likely would not exist in the present case. But some of the factors they identified as causing degradation could explain some of the differences found in the free amino acid content of fresh-fried and frozen-fried chicken. The degradations reportedly resulted in the formation of aldehydes, such as acetaldehyde, found in volatiles isolated from cooked chicken (Pippen et al., 1958). It is not known if the changes occurred during the frozen-storage period or during the reheating process. The samples analyzed in this study were reheated from the frozen state in a microwave oven. If the free amino acids were lost because of some type of degradation or decomposition, the resulting by-products could have altered the flavor of the product substantially. Our observations indicated that further investigations in amino acid content might contribute significantly toward determining the cause of flavor changes in frozen, precooked poultry meat.
Downloaded from http://ps.oxfordjournals.org/ by guest on April 7, 2015
Light
Dark Lysine Histidine Ammonia Arginine Aspartic acid Serine Glutamic acid Proline Glycine Alanine Valine Methionine Isoleucine Leucine Tyrosine Phenalanine
Frozen-fried
1137
1138
RESEARCH NOTES REFERENCES
Ambler, J. A., 1929. The reaction between amino acids and glucose. Ind. Eng. Chem. 2 1 : 47-50. Ballance, P. E., 1961. Production of volatile compounds related to the flavor of foods from the Strecker degradation of dl-methionine. J. Sci. Fd. Agri. 12 : 532-S36. Colombo, S., and C. Gervasini, 1958. Chemical investigations of free amino acids in fresh, refrigerator-stored and frozen fowl meat. Chem. Abs. 52: 20742e. Miller, J. H., L. E. Dawson and D. H. Bauer,
1965. Free amino acid content of chicken muscle from broilers and hens. J. Food Science, 30: 406-411. Pippen, E. L., M. Nonaka, F. T. Jones and F. Stitt, 1958. Volatile carbonyl compounds of cooked chicken I. Compounds obtained by air entrainment. Food Research, 23: 103-113. Schonberg, A., and R. Moubacker, 1952. The Strecker degradation of alpha-amino acids. Chem. Reviews, 50: 261-277. Swanson, M. H., and H. J. Sloan, 1953. Some protein changes in stored frozen poultry. Poultry Sci. 32: 643-649.
A. W. ADAMS, C. W. DEYOE AND A. J. KAHRS Departments of Dairy and Poultry Science, and Grain Science and Industry, Kansas State University, Manhattan, Kansas 66S02 (Received for publication May 19, 1970)
Variation in protein and amino acid content of sorghum grain, reported on by Waggle and Deyoe (1966), can result in variation in diet formula, unless the grain is analyzed and adjustments made when the diet is formulated. Waggle et al. (1967) reported that three sorghum grains containing varying amounts of protein resulted in diets ranging from 16.5 to 19.1% protein. The high-protein grain produced significantly more gain than the low-protein grain when formulated in diets of equal quantities of grain and soybean meal. However, performance of chicks was not affected by protein levels when the grain was formulated into diets of equal protein. The literature contains several reports on effect of protein levels on performance of layers. But few concern effect of frequent, short-term protein variations such as could 1
Contribution No. 785, Department of Dairy and Poultry Science and No. 722, Department of Grain Science and Industry, Kansas Agricultural Experiment Station, Kansas State University, Manhattan 66502.
occur in situations where either protein content of the grain is not known or a standard value is used. Effects of frequent, short-term protein variations on performance of laying hens are reported here. EXPERIMENTAL Shaver chicks hatched on May 31, 1968 were reared in floor pens, precision debeaked at seven days of age and redebeaked when housed. All-mash diets of 20% and 16% protein were fed ad libitum during brooding and rearing periods, respectively. Natural daylight was used throughout the rearing period. At 24 weeks of age the birds were distributed randomly, with only obvious culls removed, in four slat-litter floor pens in two similar, adjacent, naturally ventilated laying houses. Each pen (each house had two pens) measured 11 X 11 m. and housed 780 pullets, at a density of 0.12 m.2 per bird. Birds in one pen in each house were fed
Downloaded from http://ps.oxfordjournals.org/ by guest on April 7, 2015
EFFECT OF FREQUENT, SHORT-TERM DIETARY PROTEIN VARIATIONS ON PERFORMANCE OF LAYING HENS 1
RESEARCH NOTES REFERENCES
TABLE 3.—Means for various production characteristics Trait
Control
TU
Age 50% Prod, (days) Avg. Eggs/Bird Housed 40-Wk. Egg Wt. (g.) Growing Mort. (%) Laying Mort. (%) % Hatchability 1
236 38.6 86.9 15.0 14.8 54.5
241 39.2 83.7 13.8 3.7 55.0
1
Hatch of fertile eggs (36 to 41 weeks).
THE EFFECT OF FREEZING ON THE AMINO ACID CONTENT OF FRIED CHICKEN 1 JOE G. BERRY2 AND F. E. CUNNINGHAM 3 Dairy and Poultry Science Department, Kansas State University, Manhattan, Kansas 66502 (Received for publication May 16, 1970)
Ambler (1929) reported that amino acids could be destroyed through condensation with accompanying aldehydes. The reaction occurred when the medium containing the two was heated (but not boiled) and the aldehydes were not removed rap1 Contribution No. 768, Department of Dairy and Poultry Science Department, Kansas Agricultural Experiment Station, Manhattan, Kansas 66S02. "'Present Address: Department of Poultry Science, Purdue University, Lafayette, Indiana 47907. 3 Member of Faculty of Food Science.
idly. Schonberg and Moubacker (1952), in reporting on the Strecker degradation of amino acids, found that the fate of the amino acids depends upon the nature of the carbonyl compound involved. Ballance (1961) reported that degradation of methionine could be responsible for some of the volatile sulphur compounds detected in the odor of nonirradiated foods. Swanson and Sloan (1953) invested protein changes in frozen poultry and reported that freezing changed the amount of amino nitrogen. Colombo and Gervasini (1958)
Downloaded from http://ps.oxfordjournals.org/ by guest on April 7, 2015
nounced when fertility is high (Marks, 1969). Differences between TU treated and control females were small for other traits measured except laying mortality (Table 3). While the difference in laying mortality was significant (P < .05) small sample sizes may not have allowed for valid mortality estimates. The relative responses of other traits are in general agreement with comparable observations in Coturnix and chickens.
Andrews, F. N., and E. E. Schnetzler, 194S. The effect of feeding thiouracil to hens upon the thyroid gland of chicks. Endocrinology, 37: 382-384. Ershoff, B. H., 1945. Effects of thyroid feeding on ovarian development in the rat. Endocrinology, 37: 218-220. Jones, G. E. S., E. Delfs and E. C. Foote, 1946. The effect of thiouracil on reproduction in the rat. Endocrinology, 38: 337-344. Marks, H. L., 1969. Fertility of chickens fed thiouracil prior to maturity. Poultry Sci. 48: 16121618. Marks, H. L., and P. D. Lepore, 1968. The influence of selection for body weight under different environments on other quantitative traits in Japanese quail. Poultry Sci. 47 : 1691. McCartney, M. G., and C. S. Shaffner, 1950. The influence of altered metabolism upon fertility and hatchability in the female fowl. Poultry Sci. 29: 67-77. Shaffner, C. S., and F. N. Andrews, 1948. The influence of thiouracil on semen quality in the fowl. Poultry Sci. 27: 91-102. Weichert, C. K., 1930. Effect of experimental hyperthyroidism on reproductive processes in female albino rats. Physiol. Zool. 3 : 461-466.
RESEARCH NOTES TABLE 1.—Average free amino acid concentration* of fresh-fried and frozen-fried chicken Fresh-fried
Dark
Light
2.000 1.240 — 2.550 — 0.570 — 0.930 0.585 2.470 1.400 3.080 1.540 0.970 0.390 1.660 0.865 2.400 1.565 0.360 0.595 0.360 0.200 0.685 0.320 1.030 0.790 — 0.105 — 0.050
1.105 1.100 1.600 0.160 0.240 1.785 1.660 0.160 0.645 1.200 0.840 0.080 0.100 0.185
— — — —
— —
0.250 1.230 0.885 0.120 0.400 0.710 0.165 0.100 0.125 0.280 0.120 0.060
* Concentration in micromoles/1 gm. sample.
found changes in several amino acids when they compared fresh, refrigerated and frozen meat samples. Miller et al. (1965) found that, with only a few exceptions, free amino acid content of dark meat was greater than that of light meat. MATERIALS AND METHODS Meat samples were analyzed for free amino acids using the Beckman Model 120C Amino Acid Analyzer. Twenty-five grams of chopped meat, combined with 50 ml. of distilled water, were homogenized for 30 sec. in a Virtis 23 homogenizer. The samples were filtered through a layer of cheese cloth and 25 ml. of the liquid portion collected. From that sample, 20 ml. were reduced to 5 ml. in volume on a rotary evaporator. The quantity of each amino acid present was determined by the procedure outlined in Beckman's operations manual' for the analyzer. Fresh-fried and frozenfried samples were compared to determine compositional changes during storage. RESULTS AND DISCUSSION The results from the determinations of
amino acids in the frozen and fresh samples are presented in Table 1. The facilities available did not allow extensive amino acid analysis; therefore these results are from the analysis of one sample each from the frozen and the fresh-fried meat. With the exception of tyrosine and phenylalanine, all amino acids in the light meat were found to be present in greater quantities in the fresh than in the frozen meat. Without exception, the same was true for the dark meat. Differences in amounts of amino acids were more pronounced and greater amounts of free amino acids were present in the dark than in the light meat. The results generally agree with those of Miller et al. (1965). Several researchers (Ambler, 1929; Schonberg and Moubacker, 1952; Ballance, 1961) have reported on degradation of amino acids under controlled conditions that likely would not exist in the present case. But some of the factors they identified as causing degradation could explain some of the differences found in the free amino acid content of fresh-fried and frozen-fried chicken. The degradations reportedly resulted in the formation of aldehydes, such as acetaldehyde, found in volatiles isolated from cooked chicken (Pippen et al., 1958). It is not known if the changes occurred during the frozen-storage period or during the reheating process. The samples analyzed in this study were reheated from the frozen state in a microwave oven. If the free amino acids were lost because of some type of degradation or decomposition, the resulting by-products could have altered the flavor of the product substantially. Our observations indicated that further investigations in amino acid content might contribute significantly toward determining the cause of flavor changes in frozen, precooked poultry meat.
Downloaded from http://ps.oxfordjournals.org/ by guest on April 7, 2015
Light
Dark Lysine Histidine Ammonia Arginine Aspartic acid Serine Glutamic acid Proline Glycine Alanine Valine Methionine Isoleucine Leucine Tyrosine Phenalanine
Frozen-fried
1137
1138
RESEARCH NOTES REFERENCES
Ambler, J. A., 1929. The reaction between amino acids and glucose. Ind. Eng. Chem. 2 1 : 47-50. Ballance, P. E., 1961. Production of volatile compounds related to the flavor of foods from the Strecker degradation of dl-methionine. J. Sci. Fd. Agri. 12 : 532-S36. Colombo, S., and C. Gervasini, 1958. Chemical investigations of free amino acids in fresh, refrigerator-stored and frozen fowl meat. Chem. Abs. 52: 20742e. Miller, J. H., L. E. Dawson and D. H. Bauer,
1965. Free amino acid content of chicken muscle from broilers and hens. J. Food Science, 30: 406-411. Pippen, E. L., M. Nonaka, F. T. Jones and F. Stitt, 1958. Volatile carbonyl compounds of cooked chicken I. Compounds obtained by air entrainment. Food Research, 23: 103-113. Schonberg, A., and R. Moubacker, 1952. The Strecker degradation of alpha-amino acids. Chem. Reviews, 50: 261-277. Swanson, M. H., and H. J. Sloan, 1953. Some protein changes in stored frozen poultry. Poultry Sci. 32: 643-649.
A. W. ADAMS, C. W. DEYOE AND A. J. KAHRS Departments of Dairy and Poultry Science, and Grain Science and Industry, Kansas State University, Manhattan, Kansas 66S02 (Received for publication May 19, 1970)
Variation in protein and amino acid content of sorghum grain, reported on by Waggle and Deyoe (1966), can result in variation in diet formula, unless the grain is analyzed and adjustments made when the diet is formulated. Waggle et al. (1967) reported that three sorghum grains containing varying amounts of protein resulted in diets ranging from 16.5 to 19.1% protein. The high-protein grain produced significantly more gain than the low-protein grain when formulated in diets of equal quantities of grain and soybean meal. However, performance of chicks was not affected by protein levels when the grain was formulated into diets of equal protein. The literature contains several reports on effect of protein levels on performance of layers. But few concern effect of frequent, short-term protein variations such as could 1
Contribution No. 785, Department of Dairy and Poultry Science and No. 722, Department of Grain Science and Industry, Kansas Agricultural Experiment Station, Kansas State University, Manhattan 66502.
occur in situations where either protein content of the grain is not known or a standard value is used. Effects of frequent, short-term protein variations on performance of laying hens are reported here. EXPERIMENTAL Shaver chicks hatched on May 31, 1968 were reared in floor pens, precision debeaked at seven days of age and redebeaked when housed. All-mash diets of 20% and 16% protein were fed ad libitum during brooding and rearing periods, respectively. Natural daylight was used throughout the rearing period. At 24 weeks of age the birds were distributed randomly, with only obvious culls removed, in four slat-litter floor pens in two similar, adjacent, naturally ventilated laying houses. Each pen (each house had two pens) measured 11 X 11 m. and housed 780 pullets, at a density of 0.12 m.2 per bird. Birds in one pen in each house were fed
Downloaded from http://ps.oxfordjournals.org/ by guest on April 7, 2015
EFFECT OF FREQUENT, SHORT-TERM DIETARY PROTEIN VARIATIONS ON PERFORMANCE OF LAYING HENS 1