Document Type : Original Article
Authors
1
Faculty of Agriculture, Alexandria University
2
Professor of food science and technology dep., Faculty of Agriculture, Alexandria University, El-Shatby, Egypt.
3
Department of Dairy Science and Technology, Faculty of Agriculture, Alexandria University, Egypt.
Abstract
The present study was carried out to detect the effect of different storage temperature and duration on the chemical, physical and functional properties of table eggs. Eggs characterization and proximate analysis showed that the moisture content of fresh whole egg, egg white and egg yolk was found to be 72.95, 87.69 and 49.65 %, respectively. The protein content of the whole egg, white and yolk was 49.17, 93.12 and 33.21 % (on a dry weight basis). Egg-yolk and whole egg were found to contain a fat content of 59.46 and 41.96%, respectively, while egg white was almost free of fat being 0.16%. The ash content of whole eggs, white and yolk was 5.06, 5.12 and 2.38%, respectively. The weight of fresh eggs was 45.55 ± 2.41 g and decreased to a range of 42.01g to 38 g after 21 days of storage at incubation temperature. During the storage period at different conditions, a significant reduction (P ≤ 0.05) in the yolk index value was found. The albumin pH of the fresh egg was 6.86 and decreased by storage for 21 days at different conditions. The peroxide value increased from 0.704 to 0.84, 1.02, and 1.31 meq O2/kg oil for eggs stored for 21 days at refrigeration, ambient temperature, and incubation, respectively. The results illustrated that the foam capacity of eggs decreased with further storage. However, eggs stored at refrigeration had considerably higher foam capacity than those stored at ambient temperature and incubation at 32 ◦C. The results indicated that the foam of eggs stored at refrigeration was more stable than that stored at both ambient temperature and in the incubator. Oleic acid was the major fatty acid in fresh eggs accounting for 46% of the total fatty acids, whereas palmitic and linoleic acids represent 24.8 and 15.5% of the total acids. The SDS-PAGE proteins pattern showed five dominant polypeptide components and four minor bands in the egg proteins.
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