45D-6 |
Efficacy of chitosan coating on improving the shelf life of eggs during a 5-week storage at 25C |
S. D. BHALE1, H. K. No2, W. Prinyawiwatkul3, K. Nadarajah4, A. J. Farr4, S. P. Meyers3, and M. Lima1. (1) Department of Biological and Agricultural Engineering, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, (2) Dept. of Food Science & Technology, Catholic Univ. of Daegu, Hayang, 712-702, South Korea, (3) Dept. of Food Science, Louisiana State Univ. Agricultural Center, 111 Food Science Bldg., Baton Rouge, LA 70803-4200, (4) Department of Food Science, Louisiana State University Agricultural Center Quality deterioration of eggs during storage is directly related to changes in albumin and yolk. The study determined effects of chitosan coating on egg quality during a 5-week storage at 25C. Fresh grade-AA eggs coated with 0% chitosan (NC) and 1% acetic acid (A) served as the controls. Chitosans used were: low-Mw, 470 KDa; medium-Mw, 760 KDa; high-Mw, 1,100 KDa. Six chitosan-coating solutions (in acetic acid) were prepared: L (1% low-Mw), l (2% low-Mw), M (1% medium-Mw), m (2% medium-Mw), H (1% high-Mw), h (2% high-Mw). Chitosan-coating solutions were pH-adjusted to 5.60. All eggs were stored in a controlled-temperature incubator at 25C and drawn every 7 days (including day 0) for 5 weeks for analyses of weight loss, yolk-index, Haugh-unit, yolk-color (CIE-L*a*b*), and pH. Ten replications for each coating-treatment were conducted. Data were statistically analyzed (a=0.05). The lowest weight loss (5.9 %) was observed in the h-coated eggs compared to 6.6% of NC eggs. The yolk-index values of all coated eggs were significantly higher than those of NC and A eggs during a 5-week storage. Among chitosan-coated eggs, the m eggs had the highest yolk-index value throughout a 5-week storage. The Haugh units indicated that the NC and A eggs vs. the coated (l, m, h) eggs changed from grade-AA to grade-B, respectively, after 1-week vs. 3-week storage. The m-coated eggs had the highest Haugh unit ever after 4 weeks. Yolk lightness (L*) slightly decreased from 60.6-67.0 at week 1 to 56.8-66.0 after 5 weeks. The M, m, L, l coated eggs maintained yolk redness (a*) but showed increased yellowness (b*) over time. The pH of NC and A eggs increased from 7.3 to 7.6 after 5-week storage while minimal changes was observed in all coated eggs. The study demonstrated potential use of chitosan for enhancing shelf life of eggs.
Session 45D, Food Packaging: General
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