Metagenomic and flavoromic profiling reveals the correlation between the microorganisms and volatile flavor compounds in Monascus-fermented cheese

The Monascus -fermented cheese (MC) is a unique cheese product that undergoes multi-strain fermentation, imparting it with distinct flavor qualities. To clarify the role of microorganisms in the formation of flavor in MC, this study employed SPME (arrow)-GC–MS, GC-O integrated with PLS-DA to investigate variations in cheese flavors represented by volatile flavor compounds across 90-day ripening periods. Metagenomic datasets were utilized to identify taxonomic and functional changes in the microorganisms. The results showed a total of 26 characteristic flavor compounds in MC at different ripening periods (VIP＞1, p  < 0.05), including butanoic acid , hexanoic acid, butanoic acid ethyl ester, hexanoic acid butyl ester, 2-heptanone and 2-octanone. According to NR database annotation, the genera Monascus, Lactococcus , Aspergillus , Lactiplantibacillus, Staphylococcus, Flavobacterium, Bacillus, Clostridium , Meyerozyma , and Enterobacter were closely associated with flavor formation in MC. Ester compounds were linked to Monascus , Meyerozyma , Staphylococcus , Lactiplantibacillus , and Bacillus . Acid compounds were linked to Lactococcus, Lactobacillus , Staphylococcus , and Bacillus . The production of methyl ketones was closely related to the genera Monascus, Staphylococcus, Lactiplantibacillus, Lactococcus, Bacillus, and Flavobacterium . This study offers insights into the microorganisms of MC and its contribution to flavor development, thereby enriching our understanding of this fascinating dairy product .