Study On Antioxidation Of LAB26 And LAB42 From Fermented Meat Of The Dong Minority

Studies have confirmed that the lactic acid bacteria(LAB)has antioxidant,it can eliminate the DPPH·,·OH,O^2-·and other free radicals,and produce the SOD,CAT,GSH-Px and other antioxidant enzymes,which enable LAB has great prospects.The sour meat/fish of the Dong minority is a kind of natural food containing rich microbial resources.It is necessary to fully exploit and put original ecological microbial resources into use.Early research in our laboratory on LAB26(Lactobacillus curvatus)and LAB42(Pediococcus pentosaceus)from the traditional sour meat/fish showed high antioxidant activity.In this study,antioxidant properties and characteristics of the two strains were further studied,and its safety was evaluated.Finally,the two strains were used in traditional fermented sausage,and its antioxidant efficacy of the fermented sausage was evaluated.The main results and conclusions are as follows:1.Strains of LAB26 and LAB42 have exhibited good tolerability characteristics with the acid,sodium chloride,nitrite and bile salts.Two strains can survive in the environment of p H value 1.5,and grow in the environment of 8%Na Cl concentration.At the 0%?0.04%Na NO₂ concentrations,biomass of the two strains at 24h had no significant change(p<0.05).Two strains can grow well in the environment of 0.05%bile salt concentration,and tolerate the 0.5%bile salt condition.In addition,its viable cell counts more than 10⁷CFU/ml in the test of artificial simulation gastrointestinal tract,and higher than the critical value(10⁶CFU/ml)which the LAB play a role in probiotic.2.The SOD and CAT activities of strains LAB26 and LAB42 were detected,its activity of SOD enzyme was above 47.00 U/m L in cell culture of strains,and the activity of CAT enzyme was more than 1.00 U/m L in cell-free extract of strains.The study also showed that strains LAB26 and LAB42 had better abilities of nitrite degradation,its degradation rate of 24h reached 94%,and its degradation rate were negatively correlated with p H value.3.The amino acid decarboxylase test of strains LAB26 and LAB42 was negative.Strains LAB26 and LAB42 had a strong inhibitory effect on Escherichia coli,Staphylococcus aureus and Bacillus subtilis.The inhibitory effect of E.coli and Bacillus subtilis was stronger.Different strains had different antibacterial effects on the same indicator bacteria,and the same strain had different antibacterial effects on different indicator bacteria.Furthermore,in terms of sensitivity to the drug,strains of LAB26 and LAB42 were sensitive to beta lactam antibiotics,aminocyclitol antibiotics and macrocyclic lactone antibiotics,and insensitive to aminoglycoside antibiotics,quinolones antibacterial drugs.Among them,strain of LAB26 was insensitive to inhibitors of folic acid metabolic path way.4.In acute toxicity test,after the experimental mice of strains LAB26 and LAB42dealt with gavage for 14d,all the indexes were normal.The acute toxicity maximum tolerance dose(MTD)of two strains was greater than 2.0×10⁹ CFU/kg·b w,it is far greater than the ingestion of human body may ingest.The results indicated that the intake of strains LAB42 and LAB26 is safe.5.Strains of LAB26 and LAB42 were used into the manufacture of fermented sausage.The p H value of sausage quickly dropped to about 5.0 after 1d,and the p H value was 4.8 in finally,the water activity of sausage decreased from 0.94 to 0.83,the moisture content of sausage decreased from 55%to 31%,the nitrite content of sausage degraded from 96mg/kg to 30mg/kg at the 0d to 3d,and the final content was about8.0mg/kg.The chromaticity measurement and sensory evaluation of sausage showed that the value of L,a*and sensory scores of LAB fermented sausage were significantly higher than those in the control group(P<0.05).6.The amount of free fatty acid and free amino acid content improved in LAB fermented sausage.Among them,the percentage content of unsaturated fatty acids were24.59%and 24.93%in the strains LAB26 and LAB42 fermented sausage,it is significantly higher than control group(p<0.05);and the content of essential amino acids were 0.79g/100 g and 0.81g/100 g,it is significantly higher than control group(p<0.05).In the test of sausages volatile flavor material,the percentage content of esters were 24.59%and 24.93%respectively in the strains LAB26 and LAB42 fermented sausage,it is significantly higher than control group(p<0.05).This is suggesting that lactic acid bacteria fermented sausage can increase the volatile flavor of sausage.7.The clearance rate of DPPH·and·OH,reducing power,and anti-lipid peroxidation ability of LAB26 and LAB42 fermented sausage were significantly higher than those of control group(P<0.05).It showed that sausage which the LAB fermented improved the free radical scavenging ability of sausage.In summary,strains of LAB26 and LAB42 have better antioxidant activity,strong tolerance and high safety,and also show good antioxidant properties and ability of nitrite degradation in fermented sausage.They also can improve the sensory quality,nutritional value and flavor of sausage to a certain extent.It proved that the two strains of LAB vre suitable for the development of functional type fermentation agent.