Study on the Film Preservation Technology of Chinese Wolfberry Eggs

In order to study the preservation method of eggs produced by chickens which were fed with the Chinese wolfberry skin dregs,the film preservation technology was used to coat the eggs. The weight loss rate,egg yolk coefficient,Haugh unit,protein pH value,concentrated-diluted protein ratio were taken as standard to study the effects of chitosan-glacial acetic acid composite coating solution,chitosan-potassium sorbate composite coating solution,chitosan-calcium hydroxide composite coating solution,chitosan-gluten-zein composite coating solution and pullulan-glycerol-oleic acid-Tween 80 composite coating solution on the preservation of eggs. It was found that pullulan-glycerol-oleic acid-Tween 80 composite coating had the best effect on the preservation of eggs. After 25 days of storage,the weight loss rate was 5.1%,the egg yolk coefficient was 0.31 and the Haugh unit was 40,the pH value of the protein was 8.93,and the concentrated-diluted protein ratio was 0.53.On this basis,the response surface method was used to optimize the coating time and the number of coating on the weight loss rate. The optimum conditions were:coating time was 20 s,coating times was 3 times. Under this condition,the weight loss rate in the verification result was 2.78%±0.06%,the relative error between the optimized value and the predicted value was 0.007%,which showed that it was feasible to optimize the fresh-keeping process of the coating by the response surface methodology. The study found that the best coating method for eggs was pullulan-glycerol-oleic acid-Tween 80 composite coating solution for 20 s,and coating for 3 times.