Study On Preparation Of Composite Biological Preservatives And Its Antibacterial Effcet On Chilled Donkey Meat

Donkey meat is a perishable product due to the high content of unsaturated fatty acids,the actions of enzymes and microorganisms result in quality deterioration,although at 0-4 ?.For this reason,it is very important to find effective ways to inhibit the spoilage microorganisms to extend the fresh-keeping period and improve the fresh-keeping effect of donkey meat.Biological preservatives are mostly produced by natural extraction or fermentation,which are efficient and safe.According to the principle of fence technology,composite biological preservatives often have better preservation effect than single biological preservatives.The microflora of chilled donkey meat during storage was analyzed ?-Polylysine,nisin,D-sodium isoascorbate and chitosan were used as the main preservatives.Based on volatile base nitrogen value,and the p H value as the response index.The L9(33)orthogonal experiment was designed to obtain the optimal formula of the composite biological preservative: ?-polylysine 0.02%,nisin 0.06%,0.1% sodium D-isoascorbate,1.5% chitosan.The results showed that the total bacterial count,volatile basic nitrogen and p H value of chilled donkey meat were 3.97 lg CFU/g,11.45 mg/100 g and 5.87 respectively,which were in the range of first-class freshness.The tenderness increased,the chilled donkey meat showed dark red,and the muscle fiber lines were clear.At the same time,scanning electron microscope was used to observe and compare the microstructure of chilled donkey muscle after treatment with preservatives.It was found that the muscle tissue was still intact after treatment with preservatives for 18 days.By GC-MS metabonomics and microbial diversity analysis,composite biological preservative could inhibited the growth of dominant bacteria in chilled donkey meat and reduced the relative expression of microbial metabolites by reducing the relative abundance of dominant bacteria which were easy to cause spoilage.The composite biological preservative could effectively enhanced the preservation effect of chilled donkey meat,which provided theoretical support for its good quality during transportation and preservation.