Summary: | 碩士 === 大同大學 === 生物工程學系(所) === 98 === In this study, six strains isolated from local Taiwanese fermented vegetables, which could tolerate low pH conditions and high concentration of bile salts were selected for fermented three kind of lees (rice lees, sake lees and beer lees). The inhibition effects of tyrosinase activity, melanin accumulation ability and antioxidant activity of the LAB-fermented products were determined. In whitening effect, all fermented products could inhibit the activity of mushroom tyrosinase. But, only two fermented products (BE33 and BE38) could decrease melanin accumulation with 18% and 17% in A375 human malignant melanoma cells. These fermented products were frozen and adjusted as 5 mg/ml, then cultured the A375 cells at the same condition. We find the intracellular activity of tyrosinase was decrease with 28% and melanin accumulation was decrease with 25~27%. The effect of whitening was the same as the positive control, arbutin (40 mM). In antioxidation effect, the antioxidation activities of all fermented products were determined by measuring their α-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging ability, reducing ability, ferrous ion chelating ability, ABTS radical scaveng- ing ability, and intracellular ROS scavenging ability. In DPPH radical scavenging ability, all fermented products could scavenge DPPH radical. The effect of beer lees fermented products were the same as BHA (1 mg/ml), and rice and sake lees fermented products were 2-folds as BHA. In reducing ability, all fermented products had reducing ability. Three fermented products (SE7, RV12 and RN1) had stronger reducing ability, and their reducing ability were 2-folds as BHA. In ABTS scavenging ability, all fermented products could scavenge ABTS radical. The effect of beer lees fermented products were 5-folds as trolox (1 mM), and rice and sake lees fermented products were 7-folds as trolox. In intracellular ROS scavenging ability, two fermented products (SE7 and SV12) had intracellular ROS scavenging ability and the effects were similar to the control, vitamin C (1 mM). But, no chelating effect on ferrous ion was found in all fermented products. Overall, rice and sake lees fermented products had better antioxidant effect than that of beer lees fermented products.
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