Study On The Effect Of Chitosan Compound Biological Preservative On The Preservation Quality Of Chilled Meat

In order to choose the optimum proportion of chitosan compound preservative, thepreservation effect of chitosan compound preservative, consists of chitosan, nisin, tea polyphenoland lysozyme, on chilled meat during the cold storage was investigated from five aspects of thesensory quality, microbial quantity, physical properties, the decomposition of protein and fatoxidation. The results of the study are described as follows:According to the results of the preservation effect of chitosan compound preservative on thesensory quality of chilled meat by the method of single factor design, it could be conclude thatthe preservation effect of compound preservative which consisted of all the four naturalpreservative, including chitosan, nisin, tea polyphenol and lysozyme, was much better than theother compound preservative or single natural preservative. Besides, the chitosan compoundpreservative which consists of the four natural preservative, including chitosan, nisin, teapolyphenol and lysozyme, could prolong the shelf-life of chilled meat for15days, longer thanthe treatment with singe chitosan by8days.The changes of sensory evaluation of chilled meat during the storage at0~4℃for30dayswere studied, the results showed that the preservation effect of different proportion of chitosancompound preservative on the sensory quality of chilled meat was slightly different. The bestpreservation effect on the sensory quality of chilled meat was the4thtreatment group (2.0%chitosan+0.05%Nisin+2.0%tea polyphenols+0.25%lysozyme), which could hold chilled meatat the first grade for30d. However, the other proportion of chitosan compound preservativecould extend the shelf-life of chilled meat to approximately24days, and the preservation effectof the first treatment group (1.5%chitosan+0.05%Nisin+1.5%tea polyphenols+0.15%lysozyme) was the worse, which could only extend the shelf-life of chilled meat toapproximately14days.According to the research of the changes of the counts of total bacteria, EnterobacterPseudomonas and Staphylococcus aureus in chilled meat of each treatment group, we canconclude that chitosan compound preservative could inhibit the growth of these bacteria atdifferent degrees. Besides, the group which including2.0%chitosan+0.05%Nisin+2.0%teapolyphenols+0.25%lysozyme had the best antibacterial effect. What’s more, the results also showed that the antibacterial effect on the three species of bacteria was described as follows:Staphylococcus aureus>Pseudomonas>Enterobacter.The preservation effect of the group which including2.0%chitosan+0.05%Nisin+2.0%teapolyphenols+0.25%lysozyme on the drip loss, color difference and texture characteristics(including hardness, elastic, chewing force and recovery) was much better than the othertreatment groups. And which could also effectively alleviate the protein decomposition, reducethe increase of the pH value and the content of volatile basic nitrogen (TVB-N) andtrimethylamine (TMA-N), and decrease the production of hydrogen sulfide, and its shelf-life canbe prolonged for30days. However, the group which including1.5%chitosan+0.05%Nisin+1.5%tea polyphenols+0.15%lysozyme could only extend the shelf-life to15days. Andthe other treatment groups could prolong the shelf-life for approximately24days.The results showed that all of the treatment groups of chitosan compound preservativecould effectively alleviate the chilled meat in fat oxidation, reduce the increase of the value ofTBA, POV, acid and iodine. Among these treatment groups, the group which including2.0%chitosan+0.05%Nisin+2.0%tea polyphenols+0.25%lysozyme showed the greatest fatoxidation capacity, its shelf-life can be prolonged for30days, too. However, the group whichincluding1.5%chitosan+0.05%Nisin+1.5%tea polyphenols+0.15%lysozyme could onlyextend the shelf-life to15days. The preservation effect of the other treatment groups was almostthe same, and which could prolong the shelf-life for approximately24~27days.