L. paracasei 与K. marxianus 协同发酵米酸特征风味物质量变机理研究

酸汤，作为贵州苗、侗民族传统“酸食文化结晶”，倍受消费者青睐。米酸（白酸汤）与红酸汤制成的复合调味料，被广泛用于烹饪酸汤鱼等风味美食。但目前米酸发酵仍停留于传统工艺，对产酸增香菌株挖掘及其发酵体系优化少有研究，常出现风味劣变甚至腐败。因此，本课题以传统发酵米酸风味品质提升为研究目标，以前期筛选鉴定的2个产酸增香优良菌株（Lactobacillus paracasei H4-11与Kluyveromyces marxianus L1-1）为基础，构建双菌强化协同发酵的米酸风味优化模型，跟踪剖析其风味指纹图谱动态变化，以呈味L-乳酸和呈香乙酸乙酯作为主要特征风味指标，采用转录组学和蛋白组学分析，探讨酯香化合物与其前体物质（酸类及醇类）生化形成途径之间的关联，以差异基因及差异蛋白为切入点，揭示其主体风味成分形成及酶学调控机理。为发酵米酸的开发进行功能菌株挖掘、风味品质评价等提供科学依据。

Sour soup, as the traditional "crystallization of sour food culture" of the Miao and Dong nationalities in Guizhou, is very popular with consumers. The compound seasoning made from rice-acid (white sour soup) and red sour soup is widely used as cooking flavor cuisine such as Sour Soup Fish. However, rice-acid fermentation is still in the traditional process, there are few studies on the excavation of acid-producing and aroma-promoting strains and the optimization of the fermentation systems of rice-acid, this leads to flavor deterioration and even corruption frequently. Therefore, this project aims to improve the flavor quality of traditional fermented rice-acid. Based on two acid-producing and aromatizing excellent strains (Lactobacillus paracasei H4-11 and Kluyveromyces marxianus L1-1) identified in previous screening, an optimized model of rice-acid flavor with the bacteria and fungi intensified collaborative fermentation is established, and the dynamic changes of its flavor fingerprint is tracked and analyzed. Meanwhile, L-lactic acid and ethyl acetate are used as characteristic taste substance and aroma compound indicators. Using transcriptomics and proteomics analysis techniques, the relationship between ester aroma compounds and their precursors (acids and alcohols) in biochemical formation pathways will be explored. Analyzing differential genes and differential proteins as entry points, the biochemical pathways and enzymatic regulation mechanisms of the main flavor components will be revealed. This study provides a scientific basis for the evaluation of functional strains and flavor quality for the development of fermented rice-acid.