Effects Of Chitosan On The Preservation Of Fresh Pork

This subject studied antimicrobial properties of four natural preservatives(chitosan, tea polyphenols, ε-polylysine and Nisin) to common spoilage bacteria on thebasis of chilled pork. The preservatives were mixted and a response surface methodexperiment was carried out to optimize the ratio of every preservatives, and a goodresults was achieved.The results were shown as follows:(1) Effect of solvents (acetate solution) concentration, chitosan’s concentrationand deacetylation degree on bacteriostasis of chitosan to Escherichia coli was studied.When chitosan was dissolved with1%acetate solution, the antimicrobial effect wasbest. Effect of Chitosan concentration to antimicrobial activity changed with abell-shaped trend, and when chitosan concentration was1.5%, the antimicrobial effectwas best. The antimicrobial effect enhanced with the increasing of chitosan deacelationdegree. When degree of chitosan deacelation was95.6%, the antimicrobial effect wasbest.(2)By bacteriostasis effect test, we got the following results: chitosan, teapolyphenols, ε-polylysine and Nisin all had inhibiting effect to Escherichia coli,Staphylococcus aureus and Pseudomonas with different degree. Nisin had a stronginhibiting effect to Staphylococcus aureus, while had little effect to Escherichia coliand Pseudomonas bacteria.(3) Preservation effect of the four preservatives to chilled pork was studied to gota appropriate type and concentration of the compound preservative. Response surfacedesign experiment was carried out to optimize the ratio of the three preservatives. Theresults showed that interaction effects of chitosan and tea polyphenols, chitosan andε-polylysine were significant (P<0.01). Interaction effects ε-polylysine and teapolyphenols was not significant (P>0.05). The best ratio of compound preservative is:tea polyphenols3.6g/L, ε-polylysine0.4g/L, Chitosan10.4g/L.(4) Four indicators(Colony count, TVB-N, pH, contents of high iron Myoglobin)was used for reference to asses the effect of compound preservatives on chilled meat.Shelf life of compound preservative-treated was3days longer than the blank meat(shelf life of4days), better than others fresh-keeping agents in the market.