Quality Analysis Of Taihang Eggs And Study On Film Preservation Technology

Taihang eggs are high-quality poultry resources listed in Hebei Province's variety protection list.Their unique flavor is loved by consumers.Because they are mostly free-range raised,collected and transported for a long time,they are very vulnerable to corruption and deterioration,and there are potential food safety hazards.By analyzing the egg quality of Taihang eggs,this study focused on the development of edible antimicrobial fresh-keeping film with chitosan,sodium phytate and potassium sorbate as raw materials,natural,non-toxic,easy to popularize and apply,and applied it to Taihang eggs.The changes of egg quality during the storage of the film were analyzed to provide theoretical and technical basis for the storage and fresh-keeping of Taihang eggs.The external quality and internal quality of Taihang eggs were analyzed by measuring the quality indexes of Taihang eggs.The results showed that there was no significant difference in the external quality between Taihang eggs and the control group(P<0.05);in the internal quality,there was no significant difference in protein moisture,yolk moisture,yolk PH(P>0.05),Huff unit,yolk color,yolk relative weight,and egg yolk weight between Taihang eggs and the control group(P<0.05).Relative shell weight and protein pH were significantly different(P<0.05),and the quality of Taihang eggs was higher than that of the control group.Chitosan of different concentration(4%,5%,6%,7%,8%),sodium phytate of different concentration(0.75%,1%,1.5%,2%,2.5%)and potassium sorbate of different concentration(0.5%,0.75%,1%,1.25%,1.5%)were tested by single factor test at different static time of 1 min,2 min,3 min,4 min,5 min,respectively.The film thickness,light transmittance,moisture permeability and oxygen permeability were tested.The results showed that when the chitosan content was 6%,sodium phytate content was 1.5%,potassium sorbate content was 1%,and the static time was 1 min,the edible antimicrobial film had the best performance.The response test was conducted by choosing the amount of chitosan,sodium phytate and potassium sorbate as the response factors.The model was established with the film thickness,transmittance and moisture permeability as the response values.The regression equation was obtained as follows:Y=98.39-1.95A+1.68B-0.93C+2.89AB-0.79AC-0.7BC-4.17A~2-5.06B~2-5.23C~2.The preparation scheme of edible chitosan antimicrobial film was determined.The optimum performance of chitosan antimicrobial film was determined when chitosan was5.82%,sodium phytate was 1.56%and potassium sorbate was 0.955%.The edible chitosan antimicrobial fresh-keeping film was applied to the fresh-keeping research of Taihang eggs.By measuring the changes of sensory index,weight loss rate,Harrington's unit,yolk index,egg white pH and total number of colonies,the following conclusions were drawn:after 35 days of storage,the weight loss rate of Taihang eggs in the coating group was significantly lower than that in the control group(P<0.01),and the Harrington's unit and yolk index were significantly higher than those in the control group(P<0.01).In the control group(P<0.05),the pH value of egg white and the total number of colonies were significantly lower than those in the control group(P<0.05),while the weight loss rate of Taihang eggs in the refrigerated group was significantly lower than that in the coated group(P<0.05).There was no significant difference in Harrington's unit,yolk index,pH value of egg white and the total number of colonies between the coated group and the refrigerated group(P>0.05).During the whole storage period,the quality of Taihang eggs in coated group was better than that in refrigerated group,which indicated that chitosan antimicrobial preservation film could effectively inhibit the deterioration of fresh eggs,prolong the shelf life of eggs,and provide theoretical basis for the preservation of eggs with coated film.