Study On The Quality Changes And Regulation Of Cold Fresh Sanhuang Chicken

Cold fresh chicken is vulnerable to microbial contamination and the occurrence of spoilage in the cold storage process due to its own rich nutrients and environmental factors, which can result in decreased quality of chicken and short shelf life. The three yellow chicken breast was used as the object of study, first of all, the variation law of freshness index including volatile base nitrogen(TVB-N) value, pH value, the total number of colonies with time were investigated and the correlation between electronic nose signals of the volatile components and freshness index were also discussed. Second, traditional microbiological culture methods and 16 SrDNA sequencing method were developed to analyze the diversity of microorganisms of cold fresh chicken during the storage process, and dominant spoilage bacterials were determined from the cold fresh chicken, The antibacterial activities of three biological antistaling agent(Mangosteen polyphenols, tea polyphenols, Lactococcus lactis) were studied with identificated spoilage bacteria and selected the best preservative. Finally, the low field nuclear magnetic resonance method and chemical method were used to evaluate the effect of the best biological preservative on chilled chicken. The main conclusions are as follows:The result of correlation evaluation between the freshness index( pH, volatile basic nitrogen(TVB-N), and total colony)and electronic nose signal of volatile components from cold fresh three yellow breast during the process of cold storage showed that chicken samples within 1-3day was fresh meat, chicken samples within 5-7day was second fresh meat, chicken samples with the ninth day was deterioration meat; The fresh index of cold fresh chicken breast were gradually decreased with the increase chilling time. The electronic nose principal component(PCA) and linear discriminant analysis(LDA) distribution area on the map for different days chicken samples were overlapped, and good distinguish effect were got. Therefore, electronic nose technique can be used to evaluated freshness of the cold fresh chickenBy traditional microbiological culture methods and 16 SrDNA sequencing combined method, cold fresh chicken spoilage bacterials were isolated and identificated and the changes of microflora also were investigaed during the process of cold storage. The results showed that spoilage microorganisms in cold fresh chicken breast mainly were Escherichia coli, Staphylococcus aureus, lactic acid bacteria and Pseudomonas bacteria. The component of initial microflora included lactic acid bacteria and staphylococci and each accounted for 35%, enteric bacilli accounted for 29%., The Enterobactericeae accounted for the majority of 79%, lactic acid bacteria accounted for 18%, Pseudomonas aeruginosa accounted for 2%. Enterobacteriaceae and lactobacillus were dominant bacteria, Enterobacteriaceae accounted for absolute advantage.The inhibitory effect of different chemical reducing agents on dominant spoilage were carried out by the bacteriostatic ring experiment bacteria. The results showed that the antibacterial activity of compound preservative activity were stronger than single bacteriostat, and have good preservation effect. Group a preservation mixture for 0.4% mangosteen polyphenols + 1.2V per thousand lactic acid Streptococcus, group B compound preservative for 0.4% tea polyphenol + 1.2V per thousand in Lactococcus lactis were chosen, and two preservatives antibacterial activity were better.