Variation in the Physiochemical Properties of Rice Husks Driven by Long-Term Solid-State Fermentation

Abstract

Rice husks (RH) are crucial to Chinese liquor (baijiu) production, but the mechanism responsible for their contribution to baijiu quality remains unknown. In this research, variation in the physicochemical and microbial properties of rice husks resulting from fermentation was evaluated. Following fermentation, the most common aperture size (i.e, the mode) increased from 3.8 to 4.3 nm, and the specific surface area increased from 0.672 to 1.466 m²/g. The proportion of cellulose in the RH decreased from 37.3 to 31.2%. According to 16S rRNA amplicon sequencing, fermented RH contained a greater number of microorganisms than fresh RH. Fermented RH contained primarily Clostridium, representing 70% of the total microbial population. Post-fermentation RH, when soaked in raw baijiu, promotes the production of esters in the baijiu matrix. This research is expected to aid in the refinement of Chinese baijiu production processes, potentially enhancing the efficiency and sustainability of the industry.