接种发酵对酸鱼风味品质的影响及其产酯增香机制

Suanyu is a kind of Chinese traditional solid fermented freshwater fish products which is deeply loved by consumers. The lack of understanding of the characteristic fermentation flavor formation mechanism is the bottleneck that restricts the industrial production and transformation and upgrading of the traditional food. One of the key scientific problems in understanding the flavor formation mechanism is the in-depth study on the way of starter cultures producing esters in this process. With freshwater fish as the research object, this project will focus on analyzing the way of the starter's participation in the formation of characteristic ethyl ester compounds. By studying the flavor contribution of ethyl ester compounds and their correlation with starter cultures, establishing a simulation system to study the synthesis of ethyl ester compounds, and studying the ester synthase and its properties with the means of molecular biology, the role and mechanism of starter cultures in the formation of ethyl ester compounds during the fermentation of Suanyu were clarified. This study will provide theoretical guidance for the industrial standardization regulation of traditional fermented fish products, which is of great significance to enrich the processing technology of freshwater fish and promote the development of freshwater fish industry.

酸鱼是我国一种深受消费者喜爱的传统固态发酵淡水鱼制品。缺乏对淡水鱼特色发酵风味形成机制本质的理解，是制约该传统食品实现工业化规模化生产以及转型升级的瓶颈；理解风味形成机制的关键科学问题之一是对此过程中发酵剂产酯增香途径的深入研究。本项目将以淡水鱼为研究对象，重点分析发酵剂在酸鱼特征风味物质—乙酯类化合物形成过程中的参与途径；通过研究影响风味品质的关键乙酯类化合物的风味贡献及其与发酵剂的相关性，建立模拟体系研究发酵剂合成乙酯类化合物的途径，并借助分子生物手段研究发酵剂的酯合成酶及其性质，阐明发酵剂在酸鱼乙酯类风味物质形成过程中的作用与机制。本研究将为传统发酵鱼制品风味的工业标准化调控提供理论指导，对丰富淡水鱼加工技术和促进淡水鱼产业发展有重大意义。

本项目研究了接种发酵对酸鱼酯类风味物质的影响及微生物产香机制。通过仪器检测与感官评价结合最小偏二乘分析，确定了湖南湘西地区传统酸鱼的的风味轮廓；草鱼是适合酸鱼发酵的鱼种，可代替鲤鱼制作酸鱼；风味重组与风味缺失试验明确了接种发酵酸鱼的7种关键香气化合物，包括乙酸乙酯、己酸乙酯、乙酸异戊酯、丁酸乙酯、己醛、十六醛和2-戊基呋喃，其中主要乙酯类化合物-乙酸乙酯的形成与乳杆菌相关；微生物细胞内外均表现出酯酶活力且胞外的活力较高，缓冲液模拟体系证实了植物乳杆菌通过酯化和醇解两种途径合成乙酸乙酯；酯类风味前体物质脂肪酸主要由木糖葡萄球菌和酿酒酵母水解脂肪释放，植物乳杆菌无水解脂肪的能力；原核转录组学分析与蛋白功能注释明确了乳酸菌的关键酯酶为esterase（EC3.1.1.3），分子量为25483.04，pI为8.98。本研究从产香途径与酶学性质角度解析了发酵剂在酸鱼乙酯类风味物质形成与积累中的作用与机制，为传统发酵鱼制品风味的工业标准化调控提供理论指导。