Abstract:

Chitosan and vegetable oils have been widely used in preserving the internal quality of eggs. However, chitosan
can interact with water molecules to increase the water vapor permeability of chitosan films, thereby being less effective
in decreasing the weight loss of eggs during storage. Vegetable oils have a good sealing ability, but they are susceptible
to oxidization and the addition of vegetable oils to coatings retards the formation of films. In order to improve these
disadvantages, our laboratory designed 4 different chitosan-corn oil coatings and tested their abilities in preserving the
internal quality of eggs during storage. These 4 different coatings were prepared by mixing chitosan and corn oil at different
ratios (CH:CO ratio = 0:100, 30:70, 40:60, and 50:50, designated as groups A, B, C and D, respectively). In addition, VE,
citric acid, oregano essential oil and sucrose ester were beforehand added in corn oil. Later, the coated eggs were stored at
22 ℃ and 4 ℃, respectively. Results showed that group B was the best in preserving egg quality. After 45 days of storage
at 22 ℃, the eggs in group B remained at grade A, the weight, Haugh unit and yolk index of which decreased by 0.39%, 20.95
and 22.08%, respectively, and the pH of the egg white and total volatile basic nitrogen (TVB-N) content increased by 0.63 and
1.01 mg/100 g respectively. Eggs stored at 4 ℃ for 10 weeks were as fresh as those stored at 22 ℃ for 33 days. After storage at 4 ℃ for
20 weeks, the weight loss, Haugh unit, yolk index and egg white pH decreased by 0.54%, 21.56, 9.97% and 0.46, respectively. In
the meanwhile, the TVB-N content increased by 0.2 mg/100 g. Obviously，group B, containing 40% chitosan, 60% corn oil, 0.1%
oregano oil, 0.03% VE, 0.015 g/100 mL citric acid, 0.2 g/100 mL sucrose ester, has a better fresh preservation effect

Key words: coating preservation, egg, chitosan, corn oil, internal quality of eggs