Development of sweet fermented rice (Khao-Mak) production using a pure culture of Amylomyces rouxii TISTR 3182 by the mixture design approach.

A mixture design approach was used to investigate how different types of glutinous rice impacted the production of sweet fermented rice (Khao-Mak) using a pure culture of Amylomyces rouxii TISTR 3182. White glutinous rice provided the highest total soluble solids (TSS) and alcohol content (24.3 ± 0.35^oBrix and 2.0 ± 0.14%, respectively). The combination of black glutinous rice (88%) with white glutinous rice (12%) gave the highest total phenolic content (TPC) at 120.21 ± 2.20 µg GAE/mL. The optimal combination was chosen for large-scale production, yielding 22.00 ± 0.5^oBrix, 1.63 ± 0.23%, and 102.98 ± 0.76 µg GAE/mL of TSS, alcohol, and TPC, respectively. Thin-layer chromatography (TLC) revealed that the sugar obtained from the fermentation was glucose. Scanning electron microscopy (SEM) showed that growth of the fungal strain hydrolyzed the rice structure during fermentation. The crude extract of sweet fermented rice, fermented using a pure fungal strain culture through a biotechnological approach, suppressed the growth of Staphylococcus aureus DMST 2933 and Salmonella sp. ATCC 13311.

Supplementary information: The online version contains supplementary material available at 10.1007/s13197-024-06134-6.