Impact of yeast fermentation on nutritional and biological properties of defatted adlay (Coix lachryma-jobi L.)

The effects of yeast fermentation on the contents of reducing sugar and gamma-aminobutyric acid (GABA), the protein size distribution, peptide molecular weight distribution, free amino acid (FAA) composition, antioxidant activity, and tyrosinase and xanthine oxidase inhibitory activity of defatted adlay (DFA) were investigated in this study. Fermentation decreased reducing sugar content but increased GABA content. During fermentation, proteins were degraded, and large quantities of peptides with low molecular weights were produced. The total amount of FAAs increased by 9.9 times after 60 h of fermentation, and most of the FAAs gradually increased with fermentation time. Meanwhile, fermentation increased the total phenolic content, ferric reducing antioxidant power (FRAP) and 2, 2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity by 70.7%, 32.1%, and 35.4%, respectively. Furthermore, the tyrosinase and xanthine oxidase inhibitory activity of DFA increased by approximately 120% and 150%, respectively, after fermentation. Therefore, yeast fermentation was effective for improving the nutritional and biological properties of DFA.

Automated summary

Yeast fermentation altered the chemical composition of defatted adlay, increasing beneficial components such as antioxidants and amino acids, enhancing the nutritional and biological properties.