Reduction of citrinin biosynthesis by fatty acids in Monascus fermented food

Abstract

Monascus-fermented food (red yeast rice, red mould rice, angkak) contains various useful secondary metabolites, for example lovastatin, along with citrinin, a hepatonephrotoxic agent. Fatty acids such as octanoic acid, oleic acid, octadecanoic acid, decanoic acid, hexanoic acid at increasing concentrations concentrations (0.1, 0.5, 1, 3 and 5%) were incorporated in solid fermentation medium to influence the citrinin level in red mould rice. Out of all the fatty acids tested, oleic acid and octadecanoic acid were ineffective, hexanoic acid and octanoic acid were moderately effective, whereas decanoic acid was highly effective in controlling citrinin biosynthesis. On the eleventh day of solid-state fermentation in red mould rice medium supplemented with 5% decanoic acid, citrinin concentration was 28 ng/g (lower than the advisory citrinin limit of 200 ng/g), whereas lovastatin concentration was 1.574 mg/g. Fermentation of rice medium supplemented with decanoic acid could produce a safer Monascus-based functional food than the non-supplemented medium.