Characterization of Fen-Daqu Through Multivariate Statistical Analysis of H-1 NMR Spectroscopic Data

J. Inst. Brew. 117(4), 516-522, 2011 Fen liquor is typical of Chinese light-flavour liquor (alcoholic spirit), which is fermented from sorghum with Fen-Daqu powder. Fen-Daqu is a saccharifying agent and fermentation starter in this fermentation process and in Fen traditional vinegar. To investigate the changes of biochemical components in Fen-Daqu during the incubation, samples at seven incubation stages were analyzed by H-1 nuclear magnetic resonance (NMR) spectrometry and principal component analysis (PCA). This revealed clear separation of the samples obtained from different incubation stages in the principal component plots by combining PC1 and PC2, which cumulatively accounted for 93.27% of the variance. The major compounds that contributed to discrimination were acetate/alanine, arginine, ascorbate, betaine, choline, ethanol, fructose, galactose, glucose, glucitol, glycerate, lactate, maltose, mannitol, phenylalanine, proline, propylene glycol, threonine and tryptophan. These compounds were regarded as the representative metabolites or biomarkers characteristic for each incubation stage and were related with microbiological changes of importance for quality control in Fen-Daqu production.