Changes On Microbial And Quality Of Chilling Chicken During Different Sotrage Temperatures

This study used chilling chicken as raw material to investigate the affects of different low temperature conditions to the chickens quality.Research mainly includes three parts:firstly, microbial community of chilling chickens during storage was investigated and analyzed under different temperatures to get the regulation of microbial growth; Secondly,analyzed the influence of different storage temperatures on quality of chilling chickens;Finally, based the former study,found the best storage temperature of chilling chicken to keep the quality fresh and indicated the change role of endogenous enzymes at this temperature.(1) Changes in microbial community composition of chilling chicken during storageThe microfloral change in chilling chicken was explored by traditional bacterial cultivation and PCR-denaturing gradient gel eletrophoresis(PCR-DGGE). Chilling chicken was investigated at 0 d、3 d and 6 d with its inner temperature 4 ℃、0 ℃ and-1.5 ℃.Results indicated that chilling chicken has been exceed a safe threshold at 6 d 4 ℃.And the pseudomonas exhibited a rapid increase and approximated to total bacterial counts at late stage at 4 ℃.At last day,the dominant bacteria was pseudomonas at 4 ℃while dominant bacterial was staphylococcus at 0 ℃ and-1.5 ℃,the same as the results by DGGE.based on the method of traditional bacterial cultivation and PCR-DGGE,the bacteria of chilling chicken was enterobateriaceae、pseudomonas、staphylococcus、acidovorax、acinetobacter、moraxella and burkholderia.(2) Chicken quality of chilling chicken during different storage temperatureThe influence of storage conditions on the quality of chicken breast was investigated.Chicken breasts were stored under three temperatures to keep the inner temperature 4 ℃、0 ℃ and-1.5 ℃。Sensory changes and quality indicators such as p H、total volatile basic nitrogen(TVB-N)、color parameters、water holding capacity(WHC)、protein solubility and texture were determined.The sensory evaluations and TVB-N values results showed the shelf life of chicken breasts at 4 ℃ were less than 5 d,while the quality was going bad at 0 ℃ 6 d and the quality stayed well at-1.5 ℃ 6 d. The temperature and time had a high correlation to the quality of chilling chicken at storage. Compare the chilling chicken qualityat storage among 4、0 and-1.5 ℃,-1.5 ℃ was the best storage temperature to keep the chicken fresh.(3) Affects of endogenous enzymes on fat and protein of chilling chickens at-1.5 ℃storage temperaturesThe content 、 component and enzyme activity of chilling chickens at 6 d were investigated at-1.5 ℃ storage temperature to indicate the effect of storage temperature to protein and fat.The results indicated that at-1.5 ℃ the protein content went rise while content of fat went down.The was no confidently significant change at total amino acids contents 、essential amino acids and flavor amino acids.And unsaturated fatty acids went risen.The activity of protease and lipase kept stable,which was the main reason to change the chilling chicken quality at-1.5 ℃ storage.