| With the improvement of living standards,donkey meat is increasingly accepted as a nutritious meat with health care functions.However,donkey meat has the characteristics of high protein,high myoglobin content,and high unsaturated fatty acids,which determines that it is more prone to spoilage and quality deterioration than other poultry meat.However,there are little studies on the fresh-keeping and storage technology of donkey meat.This study took donkey meat as the research object,and explored the laws of physical and chemical quality and microbial changes in donkey meat during refrigerated storage at 4?.At the same time,through the MIC minimum bacteriostasis test and response surface method,the ratio of the composite biological preservative was optimized,and the cold storage period of donkey meat was prolonged.1.The test of the physical and chemical indexes of donkey meat under refrigerated storage at 4? showed that the p H value,TVC,TVB-N value,POV value,TBARS value and TBARS value all increased with the extension of storage time at 4?,indicating that microbial reproduction and fat oxidation deepen during storage of donkey meat.TVC reached 7.35 lg CFU/g on the 6th day,which exceeded the limit;and the TVB-N value exceeded 15mg/100 g on the 5th day.Based on various indicators,the shelf life of donkey meat stored at low temperature was 5 days.2.The experiment used high-throughput sequencing technology to analyze and predict the succession,dominant flora,and metabolic functions of donkey meat during the spoilage process of donkey meat at 4°C.It showed that the dominant bacteria phyla was the Proteobacteria during the entire storage period.The bacteria belong to the genera Pseudomonas,Acinetobacter and Photobacterium.Metabolic function prediction indicated that the main metabolism of refrigerated donkey meat was amino acid metabolism and carbohydrate metabolism.This result provided a theoretical reference for the targeted preliminary screening of biological preservatives.3.The biological preservatives with good antibacterial effects were screened through the MIC minimum inhibitory concentration test: ?-PL,Nisin,and tea polyphenols.Taking the TVB-N of refrigerated donkey meat as the response value,a three-factor,three-level Box-Behnken central combination experiment was designed and the analysis results showed that the inhibitory ability of the three preservatives on the TVB-N value was?-PL>Nisin>Tea polyphenol,And there was a significant interaction between ?-PL and Nisin,?-PL and tea polyphenols(p<0.01).The optimal preservative ratio after optimization was ?-PL concentration of 0.17% and Nisin concentration of 0.08%,The concentration of tea polyphenols was 1.55%.The measured TVB-N value was 12.62 mg/100 g,which was close to the model predicted TVB-N value of 12.03 mg/100 g,indicating that the prediction model was reliable.4.The experiment showed that using of the optimized compound biological preservative could effectively reduce the p H value,the increase of TVC and TVB-N values of donkey meat,and slowed down the corruption of donkey meat;the POV value,TBARS value and the value of the donkey meat at the end of storage.The carbonyl values were significantly lower than those of the control group(p<0.05);it showed that the composite biological preservative could effectively protect the fat and protein from oxidative decomposition;compared with the control group,the biological preservative group had better color and texture indicators.Therefore,the composite biological preservative optimized by response surface had good antibacterial,anti-oxidant,and quality-improving effects,and the composite biological preservative could effectively extend the shelf life of refrigerated donkey meat for more than 2 days. |
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