Study On Anti-oxidation Of Food Microbes

In this paper, the strains of food microbes in different sources((27 bacteria and 35 yeasts) were screened by the ability to scavenge 1,1-diphenyl-2-picrydrazl (DPPH) free radical and inhabit lipid peroxidation. And reducingpower, hydroxyl radical scavenging ability, superoxide radical scavenging ability and resistance to hydrogen peroxide were exprimentized. Also,the optimization of the culture medium and the resistance to imitating gastroenteric environments.The results are as followed.(1) The results showed that the 1,1-diphenyl-2-picrydrazl (DPPH) free radical and lipid inhabiting ratio by intact cells(B2～B4) and fermented brothes(Y6,Y7) were high obviously.(2) B2～B4 intact cells scavenged hydroxyl radical by 58.9%,61.0% and 64.6% respectively,with high than 0.01% Vc;scavenged superoxide radical by 4.2%,4.8% and 8.3% respectively; inhibited oxidation of 2-deoxyribose by 44.8%,54.7% and 56.5% respectively. Reducing power of 3 strains exceed to 100μmol/L cysteine hydrochloride. The three strains were less sensitive to 1 mmol/L H₂O₂ than the control group.Y6 and Y7 fermented brothes scavenged hydroxyl radical by 69.4% and 92.3%,with high than the control group; scavenged superoxide radical by 13.4% and 23.1%,with the scavenging rate of Y7 fermented brothes high than 0.01% Vc(14.7%); inhibited oxidation of 2-deoxyribose by 83.5% and 89.8%. Reducing power of two brothes was 18.0 and 61.1μmol/L cysteine hydrochloride.(3) By the orthogonal test,we optimized the culture medium:B2 strain: in 100ml medium,0.9g bran, 1g bean power, 0.8g NaCl, PH7.5.B3 strain: in 100ml medium,0.9g bran, 0.5g bean power, 0.4g CaCl₂, PH6.5B4 strain: in 100ml medium,0.6g potato starch, 1.5g bean power, 0.8g CaCl₂, PH6.5.(4) The result that the survival of B2^B4strains in imitating gastroenteric environment showed: three strains survived well both in artificial gastric fluid at PH3.0 for 2h and in artificial intestinal fluid after 1.5h.Except B3, B2 and B4 could survived at 3g/L bile for 8h.In addition, all three strains could tolerate 75g/L NaCl.