Identification and mode of action of 5-hydroxymethyl-2-furfural (5-hmf) and 1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid (MTCA) as potent xanthine oxidase inhibitors in vinegars.

Vinegars have been used as an alternative remedy for treating gout, but the scientific basis remains to be elucidated. In this study, seven commercial vinegars and one laboratory-prepared red-koji vinegar were evaluated for the inhibitory activity of xanthine oxidase (XO), a critical enzyme catalyzing uric acid formation. Red-koji vinegar exhibited potent xanthine oxidase inhibitory (XOI) activity and was used for isolating active compounds.

Characterization of White Particulates in Brine of Indigenous Fermented Foods.

White particulates were occasionally observed in the brine of indigenous fermented foods, including sufu, salt-preserved shell fish, oyster, finfish, and pork. Products with and without visible particulates were collected and brines were analyzed. The pH values, salinity, and alcohol content in brines containing particulates were slightly higher than those not containing particulates.