Antioxidant activity of two yeasts and their attenuation effect on 4‐nitroquinoline 1‐oxide induced in vitro lipid peroxidation

Summary To obtain functional yeast with antioxidant ability for food industry, the antioxidant activity of intact cell and intracellular cell‐free extract of Pichia fermentans BY5 and Issatchenkia orientalis BY10 was investigated. Both intact cell and extract of them demonstrated antioxidant activity ranged from 49% to 68%. The ability to scavenge 1, 1‐diphenyl‐2‐picrylhydrazyl free radicals were 12–41%. Furthermore, the reducing activity, Fe2+‐chelating ability, scavenging of reactive oxygen species of extracts illuminated these two isolates had excellent antioxidant ability. And then, the attenuated effect of cell‐free extracts from these two strains was evaluated using 4‐nitroquiunoline 1‐oxide (4‐NQO) as an inducing reagent. The results indicated that the addition of extraction inhibit the lipid peroxidation induced by 4‐NQO, which mainly caused by the protective intracellular protein rather than the polysaccharides. Therefore, these two yeast strains have potential to be utilised for production of functional foods.