威宁豆酱纯种发酵工艺优化及挥发性风味物质分析

Optimization of pure-culture fermentation process and volatile flavor compounds of Weining soybean paste

采用枯草芽孢杆菌(Bacillus subtilis)DX-9和异常威克汉姆酵母菌(Wickerhamomyces anomalus)DZ-3分别发酵制备威宁豆酱,以氨基酸态氮含量和感官评分为评价指标,优化制曲条件、辅料添加量及后发酵条件,并采用气相色谱-质谱联用(GC-MS)技术检测豆酱中的挥发性风味物质。结果表明,菌株DX-9和DZ-3的最佳制曲条件:接种量2%和3%、温度38℃和34℃、时间12 d和18 d;辅料最适添加量:食盐10%、辣椒5%、五香粉1.5%;菌株DX-9和DZ-3的最佳后发酵条件:温度40℃和36℃、时间均为90 d。纯种发酵豆酱的品质优于自然发酵豆酱,且菌株DX-9比DZ-3发酵的豆酱品质更佳。自然发酵、菌株DX-9和DZ-3发酵豆酱中挥发性风味物质分别检出73、50和64种,共有物质为23种,主要风味物质分别为醇类(27.36%)、酸类(75.68%)和烯烃类(64.21%)。通过主成分分析(PCA)得出威宁豆酱主要挥发性风味物质为烃类和酸类。

Weining soybean paste were made by Bacillus subtilis DX-9 and Wickerhamomyces anomalus DZ-3,respectively fermentation.The koji-making conditions,auxiliary materials addition and post-fermentation condition were optimized using amino acid nitrogen content and sensory evaluation as evaluation indicators.The volatile flavor substances in Weining bean paste were determined by GC-MS.The results showed that the optimal koji-making conditions for strains DX-9 and DZ-3 were inoculum 2%and 3%,koji-making temperature 38℃and 34℃,and time 12 d and 18 d,the optimal auxiliary materials additions were salt 10%,pepper 5%,and five-spice powder 1.5%,and the optimal post-fermentation conditions for strains DX-9 and DZ-3 were temperature 40℃and 36℃,and time 90 d.The quality of pure-culture fermented soybean paste was better than that of natural fermented soybean paste,and the quality of soybean paste fermented by strain DX-9 was better than that fermented by strain DZ-3.There were 73,50,and 64 volatile flavor substances detected in natural fermentation,strain DX-9 and DZ-3 fermented soybean paste,respectively.There were 23 common substances,and the main flavor substances were alcohols(27.36%),acids(75.68%),and olefins(64.21%),respectively.Through principal component analysis(PCA),it is concluded that the main volatile flavor substances in Weining soybean paste were hydrocarbons and acids.