Differential volatile compounds between rice and tartary buckwheat by solid-state fermentation with Monascus purpureus

The fermentation substrate influenced the quality and flavor of solid-state fermented products. Monascus purpureus solid-state fermentation was carried out with rice, tartary buckwheat (TB), and a combination of both (RTB) as fermentation substrates to explore the enrichment of functional components, the changes in the odor and volatile flavor components in Monascus fermented products. The fermentation process led to a decrease in starch content while increasing protein content and enriching the functional components in the final products. Additionally, Monascus pigments and monacolin K were produced during Monascus solid-state fermented rice (MSFR), TB (MSFTB) and RTB (MSFRTB). The fermentation of different raw materials resulted in variations in the composition of volatile flavor compounds (VFCs) in the fermented products. Compared to MSFR or MSFTB alone, MSFRTB could significantly increase the content of five VFCs, including nitrogen oxide, broad methane, sulfur organic, broad alcohol, and sulfur-chlor. The content of most VFCs in MSFRTB significantly increased compared to MSFR and MSFTB samples. Notably, VFCs such as 1-propanol, 2-methylpropanal, acetone, and ethanol were identified as the main flavor substances in MSFRTB. M. purpureus solid-state fermentation could enhance the nutritional composition, functional properties, and flavor quality of fermented products when compared to raw materials. The selection of fermentation raw materials significantly impacted the overall characteristics of the fermented products.