曲霉型豆豉后发酵过程中挥发性成分的动态变化

Dynamic Changes in Volatile Components in Aspergillus-Type Douchi during Post-fermentation

运用固相微萃取气-质联用技术对曲霉型豆豉后发酵过程中不同时期的挥发性成分进行分析,用面积归一化法测定其组分的相对含量,通过主成分分析法对其相对含量进行分析,鉴定出的整个后发酵过程中主要挥发性风味物质包括醇类5种、酯类7种、醛类3种、酸类1种、酮类1种、吡嗪类1种、烷烃类2种,共20种。随着后酵的进行,检测出的挥发性成分种类逐渐增加,其中1-辛烯-3-醇、3-甲基丁醇、2-甲基丁酸乙酯、己酸乙酯、苯乙醛、3-乙氧基丙烯、4-羟基2-丁酮、4-甲基吡嗪和2-甲基-丙酸乙酯为豆豉整个后发酵过程中主要的挥发性风味物质。而3-甲基丁醇、2-甲基丁酸乙酯、己酸乙酯、4-甲基吡嗪和2-甲基-丙酸乙酯则对豆豉后酵过程中风味形成贡献较大,且其含量随着后酵进行逐渐增加。同时,通过主成分分析得出,在整个后酵过程中15d时,样品的风味最好,25d和30d次之。

Volatile compounds in samples collected at different stages during the post-fermentation of Aspergillus-type douchi were analyzed by solid phase microextraction（SPME） combined with GC-MS and quantified by area normalization method.The major volatile flavor compounds during the whole post-fermentation process included 5 alcohols,7 esters,3 aldehydes,1 acid,1 ketone,1 pyrazine and 2 alkanes as demonstrated by PCA（principal component analysis） analysis of their relative contents.More volatile compounds were detected as the post-fermentation proceeded.1-octen-3-ol,3-methyl-1-butanol,2-methyl-butanoic acid,ethyl ester,hexanoic acid,ethyl ester,benzeneacetaldehyde,3-ethoxy-1-propene,4-hydroxy-2-butanone,tetramethyl pyrazine,2-methyl-propanoic acid and ethyl ester were predominant during the entire post-fermentation process,and 3-methyl-1-butanol,2-methyl-propanoic acid,ethyl ester,hexanoic acid,tetramethyl pyrazine,and 2-methyl-propanoic acid and ethyl ester had major contributions to the formation of flavor in Douchi and their contents increased with prolonged post-fermentation time.PCA analysis suggested that the best flavor was achieved after 15 d of post-fermentation followed by 25 d and 30 d.