基于风味组学和脂质组学研究发芽谷子气味形成机理

Germination is a kind of technology to effectively increase the value of foxtail millet. The development of germinated foxtail millet products can improve the nutritive value of foxtail millet and extend the foxtail millet industrial chain. Odor is an important edible quality of germinated foxtail millet, which determines the consumers' affection on the products. Due to the limited testing technology and lack of systematic researches, the formation mechanism of germinated foxtail millet odor is yet not clear, which affects the development and quality control of germinated foxtail millet. In this research, GC × GC TOF - MS and GC - O technology were adopted to build flavoromics technology for germinated foxtail millet, and UPLC - ESI - QTOF MS, GC, HPLC and database analysis were adopted to build lipidomics technology for germinated foxtail millet. It integrated flavoromics, lipidomics, molecular biology and statistics technology to systematically study the formation of odor components, lipid component metabolism and enzyme activity/gene expression foxtail millet during germination process, expound the change laws among lipid component metabolism of germinated foxtail millet, odor component formation and enzyme activity/gene expression, discuss their correlations and reveal the formation mechanism of germinated foxtail millet odor. The research results did not only enrich the formation mechanism of germinated foxtail millet odor but also provide theoretical and technical basis for product quality improvement and industrial production.

发芽是谷子有效增值利用技术，开发发芽谷子产品可提升谷子营养价值和延长谷子产业链。气味是发芽谷子重要食用品质，决定着消费者的喜爱程度，受检测技术水平和缺少系统研究的限制，发芽谷子气味形成机理尚不清楚，影响到了发芽谷子开发利用和品质控制。本研究拟采用GC×GC/TOF-MS、GC-O技术构建发芽谷子风味组学技术，采用UPLC-ESI-QTOF/MS、GC、HPLC、数据库分析构建发芽谷子脂质组学技术；集成风味组学、脂质组学、分子生物学和统计学技术，系统研究谷子发芽过程气味成分生成、脂质组分代谢及酶活力/基因表达的影响，阐述谷子发芽脂质组分代谢、气味成分生成及酶活力/基因表达变化规律，探讨它们之间的内在关系，揭示发芽谷子气味形成机理。该研究成果可进一步丰富发芽谷子气味形成机理，为产品品质改良和工业生产提供理论基础和技术依据。

谷子发芽会促进功能成分和营养成分的增加，同时也会导致特殊气味的产生，影响着消费者对发芽谷子的喜爱程度。为了调控和改善发芽谷子的品质，需要探明发芽谷子气味的形成机理。本项目采用GC×GC-TOF/MS技术分析发芽谷子气味成分及其在发芽过程中的变化规律，利用脂质组学考察谷子发芽过程中脂质成分的动态变化，结合相关酶活的表达规律，建立脂质-酶活-挥发性成分的内在关系。结果发现，在谷子发芽过程中初步鉴定出49种挥发性成分，其中醛类、酮类和醇类主要形成在发芽阶段，烷类和烯类主要形成在浸泡阶段。这些挥发性成分主要由脂肪酸的过氧化形成，利用模拟试验建立了6种脂肪酸与挥发性成分的内在关系，发现硬脂酸和软脂酸对发芽谷子挥发性成分形成没有贡献，棕榈油酸和亚油酸产生了大多数的醛类、酮类和醇类，亚麻酸产生了大多数的烷类。谷子发芽过程中的游离脂肪酸主要由结合态脂肪酸水解而成，对发芽谷子进行脂质组学分析，发现大多数的结合态脂肪酸在发芽过程中含量增加，而相关的脂肪酶活性也相应增加，说明结合态脂肪酸在水解为游离脂肪酸的同时，也在进行着合成，合成的速率高于结合态脂肪酸的水解速率。脂肪氧合酶、氢过氧化物裂解酶、乙醇脱氢酶活性在谷子发芽过程中活性增加，促进了发芽谷子气味的形成。。与以往食品风味研究中关注食品香气组成相比，本项目特别关注了发芽谷子气味的前体物质，具有较高的科学意义。该研究成果不仅丰富发芽谷子气味成分形成机理，为该类产品品质改良和工业化生产提供理论基础，而且对于其他谷物发芽制品的相关研究也具有重要借鉴意义。