不同菌株及制曲方式对豆瓣酱制曲效果的影响OA

To investigate the effects of fermentation strains and koji-making methods on broad bean koji production,Aspergillus oryzae strains PNM003 and HUNIANG 3.042 were applied in disc koji-making and traditional open koji-making systems.Changes in substrate temperature,microbial populations,enzymatic activities,physicochemical properties,free amino acid composition,and volatile flavor compounds were systematically analyzed during the koji-making process.The results demonstrated that disc koji-making maintained more stable substrate temperatures(30.8～34.4℃),increased mold counts by 11.52％～26.27％,and significantly enhanced protease(16.40～406.79 U·g-1)and amylase activities(1 500.06～2 062.38 U·g-1)compared with open koji-making,indicating superior enzymatic performance.Amongn the tested strains,PNM003-fermented broad bean koji exhibited the highest microbial abundance and enzymatic activities.Moreover,the broad bean koji prepared with A.oryzae PNM003 under disc koji-making conditions showed significantly lower total acidity(1.00 g/100 g)than that produced by open koji-making,along with improved visual appearance and a more favorable free amino acid taste profile.Volatile compound analysis revealed that PNM003 generated a richer and more diverse aroma profile than HUNIANG 3.042.Disc-koji-making further increased flavor diversity and reduced the proportion of musty compounds to 0.38％～2.97％.These findings indicate that disc koji-making significantly enhances the quality of broad bean koji,particularly when using the A.oryzae PNM003 strain,providing a scientific basis for optimizing Doubanjiang(broad bean paste)fermentation processes and improving product quality.