Study On The Antioxidant Activity Of Lactobacillus Paracasei HD1.7

Studies have shown that lactic acid bacteria(LAB)possess various beneficial effects such as regulation of intestinal miroflora,removement of cholesterol and stimulation of the immunity system.Some recent researches also found that LAB had antioxidant,anti-aging and other important biological functions.With the in-depth study of natural antioxidants,interests on antioxidant activities of LAB were greatly increased.In this paper,the antioxidant activities of Lactobacillus paracasei HD1.7 were systematically investigated in vivo and in vitro.Firstly,the in vitro antioxidant properties of bacteria suspension,extracellular secretion and cell free extraction were separately detected.Secondly,the in vivo antioxidant functions of bacteria suspension which indicated a higher in vitro antioxidant activity was researched on D-galatose(D-gal)induced aging mice.Finally,the antioxidant effects of HD1.7 used in air-dried sausage processing were analyzed.Results are as follows:(1)Lactobacillus paracasei HD 1.7 had scavenging activities on several free radicals.Extracellular secretion had the highest DPPH radical scavenging activity reaching 87.13%;the clearing ablities of hydroxyl and superoxide anion radical were strongest for bacterial suspension reached to 26.67%and 66.67%respectively.The reducing capacity was strongest for extracellular secretion,while bacterial suspension indicated best efficiency in chelation of Fe2+ and inhibition of linoleic acid oxidation.The bacterial suspension and extracellular secretion had similar T-AOC values,and both had different activities of GSH-Px,SOD and CAT activites.(2)Compared with the normal control group mice,D-gal model mice showed obvious oxidation aging state.The life state of Lactobacillus paracasei HD1.7 treatment group was significantly better than the D-gal model group,the organ indexes of medium dose and high dose HD1.7 treatment groups were significantly higher than those of the model group(P<0.05).Serum and liver MDA concentration of D-gal model group was significantly higher than normal control group,while SOD,GSH-Px,CAT and T-AOC values of D-gal model group were significantly lower than normal control group(P<0.05).Administration of bacterial suspension could improve SOD,GSH-Px,CAT and T-AOC values of serum and liver than D-gal model group,and the high dose treatment group was significantly improved(P<0.05).Administration of bacterial suspension could significantly reduce MDA content than D-gal model group(P<0.05).(3)Through the detection on changes of TBA,protein carbonyl and thiol content during drying and refrigeration storage of air-dried sausage,it was showed that artificial inoculation of Lactobacillus paracasei HD1.7 could significantly inhibit the oxidation of lipid and protein(P<0.05).