关键含硫化合物对菜籽油风味的影响及其形成机理研究

The flavor of rapeseed oil were usually obtained by traditional processes (hot pressing) and new clean low-consumption processes (cold pressing and microwave low-temperature pressing). It is difficult to identify and control the flavor quality in different rapeseed oil. Previous studies have shown that the rapeseed oil flavor were mainly composed of the heterocyclic compounds, fatty acids oxidation products and the degradation of glucosinolate, while recent research indicated that small molecule sulfur compounds may play an important role in rapeseed oil flavor. However, the influence of these substances on the different process rapeseed oils and the dominant precursor substances and formation mechanism are not yet clear. This research will be focus on the latest molecular sensory science research in order to explore the effect of small molecule sulfur compounds in different process rapeseed oil. Comprehensive full-component capture technology will be used integrated with aroma dilution factor analysis and aroma reorganization and elimination techniques.Rapeseed oil flavor recombination was constructed. then, screened key sulfur containing compounds were as targeted substance. The growth and decay regular of target substances in different preparations were quantified precisely through stable isotope dilution technique. Key sulfur compounds formation mechanism will be confirmed preliminary through the quantitative results, deduction process and enrichment experiments of precursor substances. This research will provide a preliminary strategy for verifying the migration rules during oil preparation, enriching and improving the flavor of rapeseed oil. It will realize the diversification and standardization of the flavor in rapeseed oil.

风味菜籽油通常采用传统工艺（热榨）和新型清洁低耗工艺（冷榨、微波低温压榨）制取，菜籽油的风味鉴别与品质控制一直是难点。以往研究表明菜籽油风味由杂环类化合物、脂肪酸氧化产物和硫代葡萄糖苷降解产物构成，最新研究表明小分子含硫化合物可能对菜籽油风味起重要作用，但该类物质对不同工艺菜籽油中的影响及主导的前体物质和形成机理尚不清楚。本研究将基于分子感官科学研究方法，融合全组分捕集技术、香气稀释因子分析技术和风味重组与省略技术，构建菜籽油风味重组物并探明不同工艺菜籽油中含硫化合物的贡献，锁定关键物质。通过稳定同位素稀释分析精准定量技术系统研究不同硫苷组分、不同制备工艺中目标物的消长规律。通过多种前体物质的推导、测定与富集实验初步明确关键含硫化合物的形成机理。本研究将为探明关键含硫化合物在制油过程中的消长规律，富集和定向改善菜籽油风味提供科学依据，实现菜籽油风味多元化和标准化。

含硫化合物（VSCs）是一类气味特征明显、阈值极低、挥发性强的小分子风味物质，但VSCs的形成机理及对菜籽油整体风味的贡献尚不清楚，严重影响了对菜籽油风味构成的科学认识和品质提升。本项目通过硫化学发光检测建立了一种灵敏、可靠的定性定量方法，结合3点选配法构建出菜籽油中5大类42种含硫化合物的数据库，主要呈现硫味、咖啡味、大蒜味、白菜味等特征风味；采用溶剂辅助风味蒸发及香气因子分析明晰了菜籽油的关键香气构成，并通过香气重组与还原明确了含硫化合物的重要作用；系统研究了不同压榨工艺下不同基因型和不同主栽品种菜籽油中VSCs的分布规律，进一步通过风味感知相互作用证明关键VSCs与异硫氰酸酯、吡嗪类之间的协同呈香作用，结合OAV筛选出低温压榨菜籽油中关键VSCs包括二甲基硫醚、二甲基三硫醚和3-甲硫基丁醛；浓香菜籽油中关键VSCs包括：糠硫醇、苄硫醇、2-甲基-3-呋喃硫醇、3-巯基-1-己醇等；最终明晰了关键含硫化合物的形成机理主要是：1）通过UPLC-MS/MS和同位素标记法在菜籽中发现S-甲基蛋氨酸（SMM）的存在，21种不同品种菜籽中SMM含量范围为0.67~32.98 mg/kg， SMM在热降解时生成二甲基硫醚的同时释放高丝氨酸。2）通过构建热反应模拟体系发现蛋氨酸可能是硫醚类物质的重要前体物，能够发生自动热氧化降解转化为3-甲硫基丙醛、甲硫醇、二甲基二硫醚、二甲基三硫醚等VSCs；半胱氨酸可能是硫醇类和噻唑类物质的重要前体物，在糠硫醇和2-甲基-3-呋喃硫醇形成过程中充当“天然硫源”的作用。3）在菜籽油鉴定出4-甲硫基丁基硫苷，热解中该硫苷可以进一步通过氧化还原、脱硫和热解过程产生二甲基硫醚、二甲基二硫醚和二甲基三硫醚重要的硫醚类化合物。通过本项目的实施突破了对传统的菜籽油风味形成途径的认识，为菜籽油风味标准的建立提供指导，从而解决影响菜籽油风味多元化、标准化的瓶颈问题之一。本项目累计申请发明专利2项，发表论文14篇，其中SCI论文11篇，包括1区论文8篇；培养硕士研究生1名、科研助理2名；入选湖北省杰出青年项目1项。

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