Study On Meat Flavoring Prepared By Synergistic Fermentation With A. Oryzae And A. Niger

Along with the rapid development of convenient food industry, meat flavoring, the keyingredients in convenient food, has become the research focus in domestic and overseas. Anew process for preparing meat flavoring by synergistic fermentation was studied.The procedures of koji prepared by A. oryzae and A. niger and fermentation wereoptimized respectively. The optimum conditions of koji-making was as the following: culturetemperature28.4℃, culture time61.3h, and ratio of A. oryzae to A. niger3.2:1(w/w).Under above conditions, the activities of acid protease and neutral protease in koji were1023U/g and2586U/g respectively. The optimum condition of fermentation was as the following:temperature44.5℃, initial pH6.9, and ratio of liquid to solid6.9:1. Under above condition,the protein recovery and degree of hydrolysis of the hydrolysate were69.0%and52.1%,respectively.Meat flavorings were prepared by synergistic fermentation method (SF) and thecommonly used enzymatic hydrolysis methods (EHs), and the physicochemical properties ofthese samples were compared. The protein recovery and degree of hydrolysis weresignificantly higher than those of EHs. The contents of umami amino acids in SF wereapparently higher than that in EHs. And the results of sensory evaluation showed that SFpossessed better taste of umami. The result of cluster analysis of free amino acids duringfermentation indicated that the initial stage (0~4h) of fermentation was the critical period forthe formation of free amino acids.The flavor compounds in different meat flavoring samples were detected by the methodof GC-MS, and111compounds were identified. These kinds of compounds possessed properproportions in meat flavoring prepared by synergistic fermentation, and pyrazine was themain flavor compounds in it. In meat flavoring samples prepared by enzymatic hydrolysis,aldehydes and ketones were the main flavor compounds. As the results of sensory evaluationshowed, meat flavoring prepared by synergistic fermentation possessed stronger smoky, nuttyand meaty flavor, and meat flavoring prepared by enzymatic hydrolysis possessed strongercaramel and meaty flavor.