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Effect of Oiling, Packaging Materials and Addition of CO2 on Quality of Shell Eggs Held in Storage
Effect of Oiling, Packaging Materials and Addition of C 0 2 on Quality of Shell Eggs Held in Storage D. A. FLETCHER, 1 H. L. ORE, 2 E. S. SNYDER2 AND A. 0 . NICHOLSON 1 (Received for publication May 21, 1958)
I
1 Canada Department of Agriculture, Ottawa, Ontario, Canada. 2 Department of Poultry Husbandry, Ontario Agricultural College, Guelph, Ontario, Canada.
that eggs kept at room temperature (70 to 80°F.) in a low concentration of C0 2 maintained their albumen quality as well as eggs held under refrigeration (50°F.), under normal atmospheric conditions. The length of storage, however, was not stated. This study was undertaken for the purpose of investigating the use of a new type of packaging material, namely a vinylidene-type copolymer (Cryovac) as compared to the current method of oil-processing. Bags of this type were chosen because of their availability, their ability to prevent entrance of outside odours, ability to retain C0 2 and for certain other desirable characteristics. MATERIAL AND METHODS
All eggs used in this experiment were obtained over a period of three days from the same well-managed, commercial flock. They were randomized into twelve groups to 6 lots each and packaged according to the 2X2X2 factorial design of oiling, vacuumizing and cartoning or traying. This constituted a total of eight treatments. In addition, four other treatments were used, consisting of a control (standard commercial oiling method), packaging in C0 2 gas, and packaging in fifteen dozen lots. Thus, twelve individual treatments were included in the experiment as summarized in Table 1. All oil-treated eggs were immersed in oil at a temperature of 120°F. for approximately fifteen seconds and allowed to drain for two minutes. The eggs subjected to various treatments were placed in new cases and properly labelled. The cases
106
Downloaded from http://ps.oxfordjournals.org/ at University of North Dakota on June 25, 2015
N CANADA only one process is recognized and used with any degree of success in the storage of eggs for long holding periods. The process is simply the immersion of the eggs in a colourless, odourless, tasteless mineral oil for several seconds, following which the eggs are drained, packed and stored in cold storage rooms maintained at a temperature of 30°F. +1° and a relative humidity of 80% ± 5 % . There are certain disadvantages associated with the present oil processing method. Oil processed eggs placed in storage, pick up foreign odours readily, and as a consequence no other product can be stored in the same room. Another undesirable feature is that numerous handlings of the eggs are required in the oil processing procedure. These handlings, along with temperature changes encountered during oil processing, tend to lower the quality of the eggs to be stored. A review of the literature revealed little experimentation with other methods of storing shell eggs. Swanson et al. (1954) reported that packaging eggs in moistureproof packages for 7 to 10 days, at a temperature of 60° to 80°F. in a C0 2 atmosphere, reduced the loss in albumen quality. Cotterill (1955) reported that gathering and storing eggs in a sealed bucket reduced the C0 2 loss and served to maintain their interior quality better than eggs gathered and stored in a wire basket. Cotterill and Gardner (1956) reported
STORAGE OF EGGS
107
TABLE 1.—List of treatments
Downloaded from http://ps.oxfordjournals.org/ at University of North Dakota on June 25, 2015
culty were shipped alternately for the months of February to May inclusive. The (1) Oiled and stored according to present commer250 mile shipping distance between cial procedure. (2) Unoiled, in a Cryovac bag, unvacuumed, in Guelph and Ottawa was considered a 1 dozen cartons. (3) Unoiled, in a Cryovac bag, vacuumed, in 1 typical commercial movement for oildozen cartons. processed eggs. Included with each ship(4) Oiled, in a Cryovac bag, unvacuumed, in 1 ment was a supply of fresh brown and dozen cartons. (5) Oiled, in a Cryovac bag, vacuumed, in 1 white-shelled eggs, obtained from the flock dozen cartons. of the Ontario Agricultural College, to be (6) Unoiled, on keyes trays in a Cryovac bag, unvacuumed, in 5-dozen lots. used as a standard by the taste panel (7) Unoiled, on keyes trays in a Cryovac bag, members, for taste and odour. Upon arrivacuumed in 5-dozen lots. (8) Oiled, on keyes trays in a Cryovac bag, un- val in Ottawa on Friday morning, the vacuumed, in 5-dozen lots. (9) Oiled, on keyes trays in a Cryovac bag, vac- eggs were immediately sorted into cookuumed, in 5-dozen lots. ing samples according to the randomiza(10) (a) Oiled, in a Cryovac bag, vacuumed, in tion table set up for that month. A code 15-dozen lots; (b) Unoiled, in a Cryovac bag, vacuumed in 15-dozen lots. system was used to identify each egg (11) Unoiled, on keyes trays in a Cryovac bag, according to shell colour, treatment, taster vacuumed, CO2 added, in 5-dozen lots. (12) Oiled, in a Cryovac bag, vacuumed, CO2 and position in taste panel. These eggs added, in 5-dozen lots. once coded were placed in one-dozen egg cartons, properly identified and held in a were then placed at random on a five household refrigerator until required. shelf rack in a clean, odourless storage Preliminary trials for cooking procedure room, maintained at a temperature of and training of taste panel were conducted 3 0 o F . ± l ° with a relative humidity of for selection of taste panel members. The 80% + 5%. A relatively uniform air move- same members were present for all tests ment was supplied by means of a Freon and the results herein reported are based type refrigeration unit, the air velocity on the data supplied by this panel. being 500 feet per minute, taken at a duct All eggs were taken from the refrigeraopening 8f X18J inches in size, in a storage tor and held at room temperature one room 6^' wide, 12' deep and 8' high. hour, before cooking. The required twelve One lot from each treatment was re- eggs, along with an additional fresh egg, moved from storage on every 4th Thus- used for checking doneness, were placed day, commencing January 12, 1956, from' in a covered aluminum kettle and the eggs the second month of storage up to the covered with five cups of cold tap water seventh month. One-half of each lot was at a temperature of 39 to 40°F. After the then packed and shipped by railway ex- water was brought to a full boil, the kettle press to the Consumer Section, Canada was removed from the heat and allowed to Department of Agriculture, Ottawa, for stand covered on a wooden board which taste panel evaluation. The remaining half served as a non-conductor. Use of a uniwas broken out at the Poultry Depart- formly preheated element for each lot ment, Ontario Agricultural College, cooked, assured uniformity. However, Guelph, and the Haugh unit value of each varying degrees of line voltage and other egg obtained by the method of Brant, factors resulted in a variation of time to Otte and Norris (1951). Exceptions to this boiling point of from seven to eleven procedure were lots 10A and 10B, which, minutes. A uniform degree of doneness because of a taste-panel sampling diffi- was assured by having the time from boil-
108
D. A. FLETCHER, H. L. ORR, E. S. SNYDER AND A. 0. NICHOLSON
ing point to serving point approximately the same—eleven minutes. For tasting, the top portion of each egg was removed, checked immediately for odour, following which the yolk and ablumen were tasted and scored by the panel for both odour and flavour, on a score rating of five to zero respectively. RESULTS AND DISCUSSION
1
MONTHS
GRAPH No. 1. Deviations of score of all treated eggs from average of fresh egg (totals).
1
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HISTOGRAM NO. 1. Deviations from fresh egg (day averages) for 12 treatments over a period of 6 months.
i
Downloaded from http://ps.oxfordjournals.org/ at University of North Dakota on June 25, 2015
The treated eggs were scored on the basis of deviations from the mean of two fresh eggs tasted each day, a treated egg scoring lower than the mean being given positive value. The sum of the deviations for each month for all treatments is shown in Graph 1. The graph indicates a general decrease over the six-month storage period in both odour and flavour scores, the decrease being more uniform for flavour than for odour scores. On the average, the odour scores were higher than flavour scores. No eggs were found to be unacceptable. In histograms 1 and 2 are shown the means of the deviations from the fresh eggs (daily average) for flavour and odour respectively, for the twelve treatments over the seven month period of the test. It will be noticed that the ratings for odour and flavour given by the taste panel to the eggs of the several treatments, tend
STORAGE OF EGGS
I
I
L_l
VACUUM
| CA*T0K NO VACUUM HOT. MLEO
HISTOGRAM NO. 2. Deviations from fresh egg (day averages) for 12 treatments over a period of 6 months.
to divide the treatments into three groups as follows: (1) A top group comprising the eggs of treatments 6, 7, 8, 9 and 10. (2) An intermediate group comprising the eggs of treatments 4, 5 and 12. (3) A lower group comprising the eggs of treatments 1, 2, 3 and 11. It is interesting to note that Group 1 includes all the treatments containing 5 and 15 dozen lots, packed on keyes trays, with the exception of treatments 11 and 12 (the C0 2 treated eggs) and the control lot 1. These treatments (11 and 12) resulted in greater deviations from the fresh eggs than the other treatments in group 1, with the result that treatment 12 appears in group 2 (oiled) and treatment 11 appears in group 3 (unoiled). Also included in group 2 are treatments 4 and 5, oiled and packaged in single dozen cartons, while in group 3 are treatments 2 and 3, unoiled and packaged in single dozen cartons. The histograms further show that treatment 1 appears in group 3. The eggs of this treatment being the only ones not packaged in Cryovac bags and therefore, the only eggs in direct contact with any possible storage odours.
Analysis of variance of the original data indicates that the difference between flavour and odour scores of the eggs stored in keyes trays and cartons was significant at the 1 percent level. The analysis of variance did not show a significant difference between oil vs. non-oil and vacuum and non-vacuum, nor does it indicate any interaction between traysXvacuumX oil. In Table 2 is shown the average Haugh unit value of the 12 treatments by months beginning with the second month of storage (January). It will be noted that the decrease in Haugh unit values over the seven-month period was similar for all treatments with the greatest loss occurring between the second and third month. In Graph 2 is shown a comparison of the Haugh unit value by month of all oiled and unoiled eggs excepting treatment 1 (Control). Evident, is the relatively small but consistent higher Haugh unit value of the eggs included in the unoiled treatments. It would appear that under the conditions of this experiment, storage of unoiled eggs for periods up to seven months has possibilites. Further experiments are in progress.
Downloaded from http://ps.oxfordjournals.org/ at University of North Dakota on June 25, 2015
I M m T»*Y
109
110
D. A. FLETCHER, H. L. ORR, E. S. SNYDER AND A. 0. NICHOLSON TABLE 2.—Average Haugh unit values of the portion of eggs broken out at O.A.C.
Treatment
1
2
3
4
5
6
7
8
9
Month January FebruaryMarch April May June Means
82 75 73 70 69 71 71
83 71 74 72 72 68 71
80 73 74 73 67 66 70
80 70 73 66 70 69 69
81 69 74 71 71 65 70
84 73 75 68 68 65 69
85 73 73 71 72 66 71
83 70 74 71 69 68 71
78 73 73 69 70 69 70
10A 10B 83
82 I
73 68 68
71 69 70
11
12
Unweighted means
84 75 77 72 73 73 74
86 76 70 73 71 70 71
82 73 74 70 70 68 71
Note 1". Sample sent to Ottawa by mistake.
Eggs divided into 12 treatments and stored for a period of seven months, were tested at four-week intervals for odour, flavour and broken-out quality. The treatments involved included the use of oil, two types of package, vacuum packing in plastic bags and addition of C0 2 . The results of this study indicate: 1. Eggs from all treatments maintained an acceptable edible quality throughout the seven-month storage period. 2. Eggs treated by the conventional method of oil processing and storage (treatment 1) received the lowest rating for odour of all treatments tested. 3. Eggs packed on keyes trays, packaged in vinylidene-type copolymer bags (Cryovac) rated significantly higher for odour and flavour than those packaged in one-dozen cartons. 4. In general a combination of oilprocessing and "Cryovac" packaging resulted in higher odour and flavour scores than was found in corresponding non-oiled samples, though not statistically significant. 5. No difference was found between eggs packed in vacuumed and nonvacuumed "Cryovac" bags.
GRAPH N O . 2. A comparison of the Haugh unit value decrease by month of the oiled and unoiled eggs heldin Cryovac.
Downloaded from http://ps.oxfordjournals.org/ at University of North Dakota on June 25, 2015
SUMMARY
111
STORAGE OF EGGS
ACKNOWLEDGMENT
The authors wish to express appreciation to the Consumer Section, Canada Department of Agriculture, Ottawa, Canada, for setting up and conducting the taste panel.
Dr. E. S. Merritt of the Canada Department of Agriculture, Poultry Division, Central Experiment Farm, Ottawa, Canada, for assistance with methods of statistical analysis and review of the paper. Dewey and Almy Chemical Company of Canada Limited, Toronto, Ontario, for supplying the "Cryovac" bags. REFERENCES Brant, A. W., A. W. Otte and K. H. Norris, 1951. Recommended standards for scoring and measuring opened egg quality. Food Technology, 5: 356-361. Cotterill, O. J., 1955. The effects of carbon dioxide mechanical shaking and threglycol on the thinning of egg white. Poultry Sci. 34:1189. Cotterill, O. J., and F. Gardner, 1956. Retention of interior shell egg quality with carbon dioxide. Poultry Sci. 35: 1138. Swanson, M. H., and N. J. Helbacka, 1954. Utilizing carbon dioxide vapour-proof packaging in the preservation of shell egg quality. Poultry Sci. 33: 1084.
Improving Albumen Quality1 K. N. HALL AND N. V. HELBACKA Department of Poultry Husbandry, University of Maryland, College Park (Received for publication May 21, 1958)
ONVINCING evidence has not been reported that the hen's diet could improve albumen quality. Little or no effect has been observed in albumen quality by varying the level of proteins, minerals, salts, grains, and fats in the ration (Thompson et ah, 1932; Card and Sloan, 1935; Griminger and Scott, 1954; Mueller, 1956; Orr et al., 1958; and Combs and Helbacka, 1958). In the two trials reported here, albumen quality was markedly improved by sup-
C
1 Scientific Article No. A693. Contribution No. 2915 of the Maryland Agricultural Experiment Station (Department of Poultry Husbandry).
plementing the feed with acidifying substances. PROCEDURE
Trial 1. During a ten-day initial period, 20 individually caged White Leghorn hens were fed an all-mash breeder ration (Table 1). When treatment began, they were divided into two groups of 10 birds each. The control group was fed an all-mash breeder ration and the test group had 3 % NH4C1 added to the same feed. The initial ambient temperature was 70°F. to 75°F. for both groups and during the treatment period it was elevated 5°F. per day. When a temperature of 95°F. was
Downloaded from http://ps.oxfordjournals.org/ at University of North Dakota on June 25, 2015
6. The addition of C0 2 resulted in lower odour and flavour scores than found in eggs of corresponding treatment. 7. In general, odour scores were higher than flavour scores. 8. Decrease in Haugh unit values over the seven-month period was similar for all treatments with the greatest drop occurring between the second and third month. 9. Under the conditions of this experiment the plastic-film enclosed unoiled eggs held a small but consistantly higher Haugh unit value throughout, than similarly packaged oiled eggs.
I
1 Canada Department of Agriculture, Ottawa, Ontario, Canada. 2 Department of Poultry Husbandry, Ontario Agricultural College, Guelph, Ontario, Canada.
that eggs kept at room temperature (70 to 80°F.) in a low concentration of C0 2 maintained their albumen quality as well as eggs held under refrigeration (50°F.), under normal atmospheric conditions. The length of storage, however, was not stated. This study was undertaken for the purpose of investigating the use of a new type of packaging material, namely a vinylidene-type copolymer (Cryovac) as compared to the current method of oil-processing. Bags of this type were chosen because of their availability, their ability to prevent entrance of outside odours, ability to retain C0 2 and for certain other desirable characteristics. MATERIAL AND METHODS
All eggs used in this experiment were obtained over a period of three days from the same well-managed, commercial flock. They were randomized into twelve groups to 6 lots each and packaged according to the 2X2X2 factorial design of oiling, vacuumizing and cartoning or traying. This constituted a total of eight treatments. In addition, four other treatments were used, consisting of a control (standard commercial oiling method), packaging in C0 2 gas, and packaging in fifteen dozen lots. Thus, twelve individual treatments were included in the experiment as summarized in Table 1. All oil-treated eggs were immersed in oil at a temperature of 120°F. for approximately fifteen seconds and allowed to drain for two minutes. The eggs subjected to various treatments were placed in new cases and properly labelled. The cases
106
Downloaded from http://ps.oxfordjournals.org/ at University of North Dakota on June 25, 2015
N CANADA only one process is recognized and used with any degree of success in the storage of eggs for long holding periods. The process is simply the immersion of the eggs in a colourless, odourless, tasteless mineral oil for several seconds, following which the eggs are drained, packed and stored in cold storage rooms maintained at a temperature of 30°F. +1° and a relative humidity of 80% ± 5 % . There are certain disadvantages associated with the present oil processing method. Oil processed eggs placed in storage, pick up foreign odours readily, and as a consequence no other product can be stored in the same room. Another undesirable feature is that numerous handlings of the eggs are required in the oil processing procedure. These handlings, along with temperature changes encountered during oil processing, tend to lower the quality of the eggs to be stored. A review of the literature revealed little experimentation with other methods of storing shell eggs. Swanson et al. (1954) reported that packaging eggs in moistureproof packages for 7 to 10 days, at a temperature of 60° to 80°F. in a C0 2 atmosphere, reduced the loss in albumen quality. Cotterill (1955) reported that gathering and storing eggs in a sealed bucket reduced the C0 2 loss and served to maintain their interior quality better than eggs gathered and stored in a wire basket. Cotterill and Gardner (1956) reported
STORAGE OF EGGS
107
TABLE 1.—List of treatments
Downloaded from http://ps.oxfordjournals.org/ at University of North Dakota on June 25, 2015
culty were shipped alternately for the months of February to May inclusive. The (1) Oiled and stored according to present commer250 mile shipping distance between cial procedure. (2) Unoiled, in a Cryovac bag, unvacuumed, in Guelph and Ottawa was considered a 1 dozen cartons. (3) Unoiled, in a Cryovac bag, vacuumed, in 1 typical commercial movement for oildozen cartons. processed eggs. Included with each ship(4) Oiled, in a Cryovac bag, unvacuumed, in 1 ment was a supply of fresh brown and dozen cartons. (5) Oiled, in a Cryovac bag, vacuumed, in 1 white-shelled eggs, obtained from the flock dozen cartons. of the Ontario Agricultural College, to be (6) Unoiled, on keyes trays in a Cryovac bag, unvacuumed, in 5-dozen lots. used as a standard by the taste panel (7) Unoiled, on keyes trays in a Cryovac bag, members, for taste and odour. Upon arrivacuumed in 5-dozen lots. (8) Oiled, on keyes trays in a Cryovac bag, un- val in Ottawa on Friday morning, the vacuumed, in 5-dozen lots. (9) Oiled, on keyes trays in a Cryovac bag, vac- eggs were immediately sorted into cookuumed, in 5-dozen lots. ing samples according to the randomiza(10) (a) Oiled, in a Cryovac bag, vacuumed, in tion table set up for that month. A code 15-dozen lots; (b) Unoiled, in a Cryovac bag, vacuumed in 15-dozen lots. system was used to identify each egg (11) Unoiled, on keyes trays in a Cryovac bag, according to shell colour, treatment, taster vacuumed, CO2 added, in 5-dozen lots. (12) Oiled, in a Cryovac bag, vacuumed, CO2 and position in taste panel. These eggs added, in 5-dozen lots. once coded were placed in one-dozen egg cartons, properly identified and held in a were then placed at random on a five household refrigerator until required. shelf rack in a clean, odourless storage Preliminary trials for cooking procedure room, maintained at a temperature of and training of taste panel were conducted 3 0 o F . ± l ° with a relative humidity of for selection of taste panel members. The 80% + 5%. A relatively uniform air move- same members were present for all tests ment was supplied by means of a Freon and the results herein reported are based type refrigeration unit, the air velocity on the data supplied by this panel. being 500 feet per minute, taken at a duct All eggs were taken from the refrigeraopening 8f X18J inches in size, in a storage tor and held at room temperature one room 6^' wide, 12' deep and 8' high. hour, before cooking. The required twelve One lot from each treatment was re- eggs, along with an additional fresh egg, moved from storage on every 4th Thus- used for checking doneness, were placed day, commencing January 12, 1956, from' in a covered aluminum kettle and the eggs the second month of storage up to the covered with five cups of cold tap water seventh month. One-half of each lot was at a temperature of 39 to 40°F. After the then packed and shipped by railway ex- water was brought to a full boil, the kettle press to the Consumer Section, Canada was removed from the heat and allowed to Department of Agriculture, Ottawa, for stand covered on a wooden board which taste panel evaluation. The remaining half served as a non-conductor. Use of a uniwas broken out at the Poultry Depart- formly preheated element for each lot ment, Ontario Agricultural College, cooked, assured uniformity. However, Guelph, and the Haugh unit value of each varying degrees of line voltage and other egg obtained by the method of Brant, factors resulted in a variation of time to Otte and Norris (1951). Exceptions to this boiling point of from seven to eleven procedure were lots 10A and 10B, which, minutes. A uniform degree of doneness because of a taste-panel sampling diffi- was assured by having the time from boil-
108
D. A. FLETCHER, H. L. ORR, E. S. SNYDER AND A. 0. NICHOLSON
ing point to serving point approximately the same—eleven minutes. For tasting, the top portion of each egg was removed, checked immediately for odour, following which the yolk and ablumen were tasted and scored by the panel for both odour and flavour, on a score rating of five to zero respectively. RESULTS AND DISCUSSION
1
MONTHS
GRAPH No. 1. Deviations of score of all treated eggs from average of fresh egg (totals).
1
lt(»
1
i
i
:i i ~
U
,««.
D D
w .
*.l
«.t
i
• KtTEl T«AV
,', u ni
C**TM HO VACUUM HOT M L »
HISTOGRAM NO. 1. Deviations from fresh egg (day averages) for 12 treatments over a period of 6 months.
i
Downloaded from http://ps.oxfordjournals.org/ at University of North Dakota on June 25, 2015
The treated eggs were scored on the basis of deviations from the mean of two fresh eggs tasted each day, a treated egg scoring lower than the mean being given positive value. The sum of the deviations for each month for all treatments is shown in Graph 1. The graph indicates a general decrease over the six-month storage period in both odour and flavour scores, the decrease being more uniform for flavour than for odour scores. On the average, the odour scores were higher than flavour scores. No eggs were found to be unacceptable. In histograms 1 and 2 are shown the means of the deviations from the fresh eggs (daily average) for flavour and odour respectively, for the twelve treatments over the seven month period of the test. It will be noticed that the ratings for odour and flavour given by the taste panel to the eggs of the several treatments, tend
STORAGE OF EGGS
I
I
L_l
VACUUM
| CA*T0K NO VACUUM HOT. MLEO
HISTOGRAM NO. 2. Deviations from fresh egg (day averages) for 12 treatments over a period of 6 months.
to divide the treatments into three groups as follows: (1) A top group comprising the eggs of treatments 6, 7, 8, 9 and 10. (2) An intermediate group comprising the eggs of treatments 4, 5 and 12. (3) A lower group comprising the eggs of treatments 1, 2, 3 and 11. It is interesting to note that Group 1 includes all the treatments containing 5 and 15 dozen lots, packed on keyes trays, with the exception of treatments 11 and 12 (the C0 2 treated eggs) and the control lot 1. These treatments (11 and 12) resulted in greater deviations from the fresh eggs than the other treatments in group 1, with the result that treatment 12 appears in group 2 (oiled) and treatment 11 appears in group 3 (unoiled). Also included in group 2 are treatments 4 and 5, oiled and packaged in single dozen cartons, while in group 3 are treatments 2 and 3, unoiled and packaged in single dozen cartons. The histograms further show that treatment 1 appears in group 3. The eggs of this treatment being the only ones not packaged in Cryovac bags and therefore, the only eggs in direct contact with any possible storage odours.
Analysis of variance of the original data indicates that the difference between flavour and odour scores of the eggs stored in keyes trays and cartons was significant at the 1 percent level. The analysis of variance did not show a significant difference between oil vs. non-oil and vacuum and non-vacuum, nor does it indicate any interaction between traysXvacuumX oil. In Table 2 is shown the average Haugh unit value of the 12 treatments by months beginning with the second month of storage (January). It will be noted that the decrease in Haugh unit values over the seven-month period was similar for all treatments with the greatest loss occurring between the second and third month. In Graph 2 is shown a comparison of the Haugh unit value by month of all oiled and unoiled eggs excepting treatment 1 (Control). Evident, is the relatively small but consistent higher Haugh unit value of the eggs included in the unoiled treatments. It would appear that under the conditions of this experiment, storage of unoiled eggs for periods up to seven months has possibilites. Further experiments are in progress.
Downloaded from http://ps.oxfordjournals.org/ at University of North Dakota on June 25, 2015
I M m T»*Y
109
110
D. A. FLETCHER, H. L. ORR, E. S. SNYDER AND A. 0. NICHOLSON TABLE 2.—Average Haugh unit values of the portion of eggs broken out at O.A.C.
Treatment
1
2
3
4
5
6
7
8
9
Month January FebruaryMarch April May June Means
82 75 73 70 69 71 71
83 71 74 72 72 68 71
80 73 74 73 67 66 70
80 70 73 66 70 69 69
81 69 74 71 71 65 70
84 73 75 68 68 65 69
85 73 73 71 72 66 71
83 70 74 71 69 68 71
78 73 73 69 70 69 70
10A 10B 83
82 I
73 68 68
71 69 70
11
12
Unweighted means
84 75 77 72 73 73 74
86 76 70 73 71 70 71
82 73 74 70 70 68 71
Note 1". Sample sent to Ottawa by mistake.
Eggs divided into 12 treatments and stored for a period of seven months, were tested at four-week intervals for odour, flavour and broken-out quality. The treatments involved included the use of oil, two types of package, vacuum packing in plastic bags and addition of C0 2 . The results of this study indicate: 1. Eggs from all treatments maintained an acceptable edible quality throughout the seven-month storage period. 2. Eggs treated by the conventional method of oil processing and storage (treatment 1) received the lowest rating for odour of all treatments tested. 3. Eggs packed on keyes trays, packaged in vinylidene-type copolymer bags (Cryovac) rated significantly higher for odour and flavour than those packaged in one-dozen cartons. 4. In general a combination of oilprocessing and "Cryovac" packaging resulted in higher odour and flavour scores than was found in corresponding non-oiled samples, though not statistically significant. 5. No difference was found between eggs packed in vacuumed and nonvacuumed "Cryovac" bags.
GRAPH N O . 2. A comparison of the Haugh unit value decrease by month of the oiled and unoiled eggs heldin Cryovac.
Downloaded from http://ps.oxfordjournals.org/ at University of North Dakota on June 25, 2015
SUMMARY
111
STORAGE OF EGGS
ACKNOWLEDGMENT
The authors wish to express appreciation to the Consumer Section, Canada Department of Agriculture, Ottawa, Canada, for setting up and conducting the taste panel.
Dr. E. S. Merritt of the Canada Department of Agriculture, Poultry Division, Central Experiment Farm, Ottawa, Canada, for assistance with methods of statistical analysis and review of the paper. Dewey and Almy Chemical Company of Canada Limited, Toronto, Ontario, for supplying the "Cryovac" bags. REFERENCES Brant, A. W., A. W. Otte and K. H. Norris, 1951. Recommended standards for scoring and measuring opened egg quality. Food Technology, 5: 356-361. Cotterill, O. J., 1955. The effects of carbon dioxide mechanical shaking and threglycol on the thinning of egg white. Poultry Sci. 34:1189. Cotterill, O. J., and F. Gardner, 1956. Retention of interior shell egg quality with carbon dioxide. Poultry Sci. 35: 1138. Swanson, M. H., and N. J. Helbacka, 1954. Utilizing carbon dioxide vapour-proof packaging in the preservation of shell egg quality. Poultry Sci. 33: 1084.
Improving Albumen Quality1 K. N. HALL AND N. V. HELBACKA Department of Poultry Husbandry, University of Maryland, College Park (Received for publication May 21, 1958)
ONVINCING evidence has not been reported that the hen's diet could improve albumen quality. Little or no effect has been observed in albumen quality by varying the level of proteins, minerals, salts, grains, and fats in the ration (Thompson et ah, 1932; Card and Sloan, 1935; Griminger and Scott, 1954; Mueller, 1956; Orr et al., 1958; and Combs and Helbacka, 1958). In the two trials reported here, albumen quality was markedly improved by sup-
C
1 Scientific Article No. A693. Contribution No. 2915 of the Maryland Agricultural Experiment Station (Department of Poultry Husbandry).
plementing the feed with acidifying substances. PROCEDURE
Trial 1. During a ten-day initial period, 20 individually caged White Leghorn hens were fed an all-mash breeder ration (Table 1). When treatment began, they were divided into two groups of 10 birds each. The control group was fed an all-mash breeder ration and the test group had 3 % NH4C1 added to the same feed. The initial ambient temperature was 70°F. to 75°F. for both groups and during the treatment period it was elevated 5°F. per day. When a temperature of 95°F. was
Downloaded from http://ps.oxfordjournals.org/ at University of North Dakota on June 25, 2015
6. The addition of C0 2 resulted in lower odour and flavour scores than found in eggs of corresponding treatment. 7. In general, odour scores were higher than flavour scores. 8. Decrease in Haugh unit values over the seven-month period was similar for all treatments with the greatest drop occurring between the second and third month. 9. Under the conditions of this experiment the plastic-film enclosed unoiled eggs held a small but consistantly higher Haugh unit value throughout, than similarly packaged oiled eggs.