Microorganisms and characteristic volatile flavor compounds in Luocheng fermented rice noodles.

The association between the appealing flavors of Luocheng fermented rice noodles (LCFN) and microbial succession during long-term fermentation is poorly understood. This study aims to elucidate the mechanism of flavor formation in LCFN during fermentation over a 30-day period. The electronic nose results showed that the LCFN underwent a flavor shift in 7-10 days with maturation in 15-30 days. This transformation was associated with the formation of characteristic flavors of (E)-2-decenal, 2-undecenal, (E, E)-2,4-decadienal, (E)-2-octenal, (E)-2-heptenal, hexanal, nonanal, and 2-pentyl furan, which had significant positive correlation with palmitic acid, oleic acid, and linoleic acid. Changes in lipase activity and the analysis of metagenomics, suggested that the characteristic flavors may be produced by Lactobacillaceae and Geotrichum via lipid metabolism. This study provides theoretical guidance for the screening of safe and efficient microorganisms for the production of flavorful rice noodles.