Protective Activity of Purple Sweet Potato Extract-added Soymilk Fermented by Bacillus subtilis against Oxidative Stress

摘要

This study focused on the development of a Bacillus subtilis-fermented soymilk with strong antioxidative activity. In a previous study, we manufactured the protective effect of various kinds of Bacillus sp.-fermented soymilks (FSMs) against oxidative stress, and selected the FSM showing the strongest activity. To elevate the antioxidative activity and taste of FSM, 5% purple sweet potato extract (PSPE) was added to FSM based on the results of radical scavenging activities and sensory evaluations. The 5% PSPE added-FSM (PFSM) scavenged 2,2-diphenyl-1-picrylhydrazyl to 70.5% and ·OH to 97.4% at the concentration of 500 μg/mL. Furthermore, the protective effects of PFSM from nitric oxide, superoxide anion, and peroxynitrite produced by sodium nitroprusside, pyrogallol, and 2-morpholinosydnonimine were evaluated in LLC-PK_1 cells. The free radical generators led to losses of cell viability, while PFSM treatment significantly increased cell viability. The present study offers support for the development of a functional B. .subtilis-fermented soymilk product using PSPE.