乳酸菌发酵鱼干中氨基酸变化及呈味分析

Analysis of Amino Acid Changes and Flavour Presentation in Dried Fish Fermented with Lactic Acid Bacteria

为探究乳酸菌混合发酵对低盐腌制草鱼发酵前后的氨基酸含量变化及主要呈味物质影响,以低盐腌制的草鱼为研究对象,采用长双歧杆菌、嗜酸乳杆菌、干酪乳杆菌、嗜热链球菌、乳双歧杆菌质量比为1∶1∶1∶1∶1的混合菌种对低盐腌制鱼干进行发酵,比较发酵前后鱼干的色差、氨基酸含量、质构特性、挥发性成分以及氨基酸态氮含量。结果表明,最佳发酵条件为环境湿度85%,温度20℃,在此发酵条件下,鱼肉中游离氨基酸含量显著增加,鲜味氨基酸含量从24.3%增加到57.9%,鱼肉的白度值上升,弹性增加,硬度、胶黏性和咀嚼性呈现出明显的下降趋势。氨基酸态氮的含量从0.226%上升至0.423%;庚醛含量从4.17%下降到0.59%,产生了丁香油酚、吲哚等风味物质,降低了鱼腥味,同时产生了新的风味物质。

To investigate the effect of mixed fermentation of lactic acid bacteria on the change of amino acid content and the main flavouring substances of low-salt cured grass carp before and after fermentation,a mixture of Bifidobacterium longum,Lactobacillus acidophilus,Lactobacillus casei,Streptococcus thermophilus and Bifidobacterium lactis in the abundance mass ratio of 1∶1∶1∶1∶1 was used to ferment the low-salt cured dried fish,and the colour difference,textural characteristics,volatile components and amino acid content of the dried fish were compared before and after fermentation.The results showed that the optimum fermentation conditions were 85%humidity and 20℃.Under these fermentation conditions,the free amino acid content of the fish meat increased significantly,the fresh amino acid content increased from 24.3%to 57.9%,the whiteness value of the fish meat increased,the elasticity increased,and the hardness,stickiness and chewiness showed a significant decrease.The content of amino acid nitrogen increased from 0.226%to 0.423%;the content of heptanal decreased from 4.17%to 0.59%,producing flavour substances such as eugenol and indole,which reduced the fishy flavour,while generating new flavour substances.