Abstract:

A total of 300 fresh eggs were randomly allocated into 6 treatment groups, and coated with 0, 0.5, 1.0, 1.5, 2.0 g/100 mL and 2.5 g/100 mL of chitosan. Then the eggs were stored at 25 ℃ for 5 weeks. Ten eggs were chosen from every treatment per week for determination of the weight loss ratio, Haugh unit, yolk index and albumen pH. The result showed that after 5 weeks storage, the weight loss ratio and albumen pH were significantly increased (P＜0.05), meanwhile, the Haugh unit and yolk index of the eggs significantly decreased (P＜0.05) in non-chitosan coated egg group. At 5 wk, compared with the eggs nocoated with chitosan, the weight loss ratio of all the eggs coated with chitosan was significantly decreased (P＜0.05) and yolk index was significantly increased (P＜0.05). The Haugh unit of the eggs coated with 1.0, 1.5, 2.0 g/100 mL and 2.5 g/100 mL chitosan was significantly increased (P＜0.05) and albumen pH was significantly decreased (P＜0.05). It had no significant difference on the weight loss ratio, Haugh unit, yolk index and albumen pH among the eggs coated with 1.5, 2.0 and 2.5% of chitosan(P＞0.05). The grade of the eggs coated with 0.5 g/100 mL chitosan at 5 wk was C , which was equal to the grade of the eggs nocoated at 3 wk. The grade of the eggs coated with 1.0, 1.5, 2.0 g/100 mL and 2.5 g/100 mL chitosan at 5 wk was B , which was equal to the grade of the eggs nocoated at 2 wk. The shelf life of eggs were prolonged significantly by coating of chitosan.

Key words: chitosan, egg quality, haugh unit, yolk index, albumen pH value