Influence Of Cold Plasma On Sterilization And Quality Of Fresh Beef

Fresh beef in the processing,transportation,sales and other links is very easy to breed microorganisms,causing beef corruption,resulting in waste of resources.Effective control of the number of microbes in fresh beef is of great significance to extend the shelf life.The effect of traditional sterilization methods on the quality of heat-sensitive fresh meat is widely studied at present,low temperature plasma on fresh meat sterilization research has just started in the International,and the impact of fresh meat quality research is rare.This topic aims at the low-temperature plasma treatment of fresh beef after air-conditioning packaging,optimize its processing technology without affecting the a*value.The effects of low temperature plasma treatment on the sensory quality and safety of beef during storage were studied,which provided a reference for the application of cold source plasma in the industrial application of fresh beef.The main results are as follows:1.Effect of low temperature plasma process parameters on the sterilization efficiency of beefThe effects of different dielectric materials and thickness on the plasma treatment were studied with the bactericidal rate and the a*value of beef as the evaluation index.The results showed that the higher the dielectric constant of the insulating medium,the higher the sterilization rate and a*value.the thinner the dielectric plate,the higher the sterilization rate,but the lower the a*value.The single factor test combined with the response surface test method optimized the voltage,treatment time and O2 ratio,the results showed that the three factors can significantly affect the beef sterilization rate and a*value.There was a significant interaction between the factors:O2 ratio,the treatment time on the bactericidal rate of the critical value decreases linearly with increasing voltage,The critical value of the effect of voltage on the bactericidal rate decreases linearly with increasing O2 ratio and processing time.without significantly reducing the sensory a*value.the optimum treatment conditions were as follows:treatment time 86 s,voltage 72 kV,O2,CO2,N2 concentration were 35%,35%,30%.The experimental results showed that the actual a*value was 19.74 and the sterilization rate was 93.75%,which was consistent with the predicted value.2.Effects of low temperature plasma on color and texture of beef storageThe quality change of low temperature plasma treated beef during storage was studied,and the differences of air treatment,MAP and MAP+CP were compared.The results showed that low temperature plasma could significantly increase the L*value and decrease the value of a*,which had no significant effect on b*value and the juice loss rate of beef.The effect of plasma on the texture of beef was reflected in the following aspects:plasma makes shear,hardness,adhesive and chewiness lower,and the quality of beef was better;it had no significant effect on elasticity,cohesion and recovery.The correlation analysis showed that the higher the water holding capacity of beef,the smaller the loss of nutrients and other ingredients,the higher the total amount of myoglobin,the color of beef will have a certain positive impact.There was a significant positive correlation between the shearing force,the hardness,the tackiness and the chewiness of the beef,and the beef taste was more delicate and the acceptability was higher.The low temperature plasma could improve the sensory quality of fresh beef as a whole.3.Effects of low temperature plasma on microbial biomass and biogenic amines in beef storageChanges in the composition of the gaseous components in the box during the storage of the beef and the pH value,the microbial,the volatile base nitrogen,the nitrite,the·malondialdehyde,the biogenic amines and other safety indicators of the beef were detemined,and the differences of air treatment,MAP and MAP+CP were compared.The results showed that low temperature plasma could significantly reduce the microbial,volatile nitrogen and pH of beef samples in 7 days,but significantly increased the content of malondialdehyde in beef(not exceeding safety standard).Five kinds of biological amine can be detected in the beef,plasma can significantly reduce the content of putrescine,while the inhibition of other biological amine was not significant.The results of principal component analysis showed that there were significant positive correlations between corruption index,microbial and carbon dioxide changes.The contents of biogenic amines(except for heparin)and malondialdehyde were significantly correlated with Enterobacter and Pseudomonas.Low temperature plasma treatment in a certain period of time can inhibit the growth of microorganisms,reduce the accumulation of some biological amines,improve the safety of fresh beef.