COMPARATIVE ANALYSIS OF FREE AMINO ACIDS AND VOLATILE FLAVOR COMPONENTS OF SUFU PRODUCED BY DIFFERENT FERMENTATION METHODS

摘要

Pre-fermentation plays a vital role in the processing of sufu. The quality of sufu made using different microbes tends to vary. Here, we performed mixed fermentation and single-strain fermentation using Mucor racemosus and Rhizopus oryzae to produce sufu. The free amino acids and volatile flavor components of sufu prepared by the 3 fermentation methods were detected by an automatic amino acid analyzer and GC-MS, respectively. In mixed-fermented sufu, the total amounts of free amino acids, flavor amino acids, hydrophobic amino acids, and essential amino acids were superior those obtained by fermentation using either strain singly. Mixed-fermented sufu also showed the lowest content of free tyrosine, reducing the undesirable "white spot" phenomenon of sufu. Volatile flavor compounds in mixed-fermented sufu better than those of single-fungus fermentation. We demonstrated that mixed fermentation can improve the flavor and quality of sufu.