Effect Of Antioxidant Properties Of Lactic Acid Bacteria On Color Of Fermented Sausage

In this thesis,in order to explore the main factors affecting the color of fermented sausage,the effects of different amounts of sodium chloride,sodium nitrite and sodium ascorbate on the color of sausage meat were compared to determine the formula that was most conducive to the color of sausage.Different fermentation methods were used for sausage fermentation.The correlation between the physicochemical indexes of sausage and color was analyzed by correlation analysis.The effect of lipid oxidation on color stability during sausage fermentation was analyzed by principal component analysis.Lactobacillus helveticus TR1-1-3 had strong growth ability in the environment of p H4.5-6.5,and could tolerate 6%sodium chloride and 0.015%Na NO₂,and had good fermentation characteristics.In addition,the DPPH free radical scavenging rate of Lactobacillus helveticus TR1-1-3 was as high as 94.35%,which indicated that the strain had strong antioxidant properties.The results of color analysis of minced meat with different additions of sodium chloride,sodium nitrite and sodium ascorbate in the ratio of fat to lean（2:8）showed that the most favorable formula for sausage color was 2%sodium chloride,0.01%sodium nitrite and 0.05%sodium ascorbate.From the perspective of the effect of different fermentation methods on the color of sausages,the moisture content of fermented sausages in TR1-1-3 group decreased to30.6%and the water activity was 0.729 after 13 days.The hardness and cohesiveness were significantly higher than those in the natural group（ZR）.The addition of lactic acid bacteria improved the quality of sausages;the relative content of metmyoglobin was lower than that of ZR group after 6 days,and the color rate reached the highest 80.7%at28 days,which was significantly higher than that of ZR group 78.63%,indicating that the addition of lactic acid bacteria improved the color of sausage.The correlation analysis showed that the a*value of fermented sausage was positively correlated with water activity（the correlation coefficient was 0.480）,the L*value was negatively correlated with hardness（the correlation coefficient was-0.888）,the b*value was positively correlated with water content（the correlation coefficient was 0.910）and water activity（the correlation coefficient was 0.876）,and negatively correlated with hardness（the correlation coefficient was-0.888）.Therefore,lactic acid bacteria TR1-1-3 improved the color of fermented sausage by improving the physical and chemical quality of fermented sausage.From the perspective of lipid oxidation and color stability of sausage,the thiobarbituric acid reactive substances（TBARS）in TR1-1-3 group were significantly lower than those in ZR group（p<0.05）after 1 day of fermentation,and the addition of lactic acid bacteria inhibited the oxidation of sausage.After 13 days of fermentation,TR1-1-3 group increased one kind of aldehyde and the content of aldehyde compounds was higher than that of natural group.Principal component analysis showed that TBARS value（load value 0.965）was negatively correlated with the relative content of a*value（load value-0.924）.Nonanal（load value 0.969）,hexanal（load value 0.962）and decanal（load value 0.946）were determined as the key factors of lipid oxidation affecting the color stability of fermented sausage.In summary,this study can provide a theoretical basis for improving the color of fermented sausage.