Abstract:Yeast protein was used as the main raw material for the preparation of flavor substances by cooperative fermentation with bacteria and enzymes and enzymatic hydrolysis，respectively. The physicochemical indexes of the hydrolysates prepared with the two methods and the sensory quality of flavor substances obtained after Maillard reaction were determined. The results showed that the degree of hydrolysis，protein recovery，total nitrogen content，peptide nitrogen content，and amino acid nitrogen content of the hydrolysate obtained by cooperative fermentation with bacteria and enzymes were 48.0%，48.0%，100.5%，122.5%，and 82.3%，respectively，higher than those obtained by the enzymatic hydrolysis method. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis（SDS-PAGE）results showed that the protein molecular weight of hydrolysate obtained by cooperative fermentation was less than 4.6 kDa，which was lower than that obtained by enzymatic hydrolysis.The composition of free amino acids in the hydrolysates produced with the two methods was significantly different. Particularly，the proportion of essential amino acids in the hydrolysate obtained by cooperative fermentation was 45% higher than that obtained by enzymatic hydrolysis. Solid - phase microextraction - gas chromatography-mass spectrometry（SPME-GC-MS）results showed that the flavor substances in the two products were quite different，especially in alcohols and the content of acids. The results of sensory evaluation showed that the product prepared bycooperative fermentation had reduced odour and burnt smell and enhanced fruit and meat aromas（p＜0.05）.