苦荞加工前处理对芦丁和槲皮素转化响应机理的研究

Tartary buckwheat (TB) is a special crop, origins in China, can be used as food and traditional Chinese drug. About 90% of TB was grown in China. Flavonoids is a kind of the most important functional components in TB which has been widely studied. Rutin is the mainly flavonoids in TB, small amounts of quercetin and isoquercitrin with higher functional activities were also found. Previously, our studies indicated that the rutin content in TB accounted for 69.4-95.0% of total flavonoids, meanwhile, the rutin and quercetin may convert into each other during the pretreatment of soaking and steming during the process of TB tea. This proposal will be mainly focus on the following research: (1) To purify and characterize the key enzymes involved in the bioconversion between rutin and quercetin using modern isolation and purification techniques, SDS-PAGE, Q-TOF-MS/MS ect.; (2) To analyze the biological properties of these enzymes; (3) To investigate the activities of these enzymes and the flavonoid compounds contents at different stages in the treatments of soaking and steaming; (4) To develop techniques for regulating the bioconversion between rutin and quercetin during pre-treatment of soaking and steaming in the process of TB. This study may provides the theories basis and technical supports for processing TB teat and other TB foods with higher functional activities.

苦荞麦，学名鞑靼荞麦，是中国特有的药食兼用粮食作物，世界上90%以上的苦荞产于中国。黄酮类化合物是苦荞中最重要的生物活性物质之一被广泛研究，其中芦丁含量最高，此外还含少量功能活性更强的槲皮素和异槲皮素。项目申请者发现苦荞籽粒中芦丁占总黄酮含量的69.4-95.0%，在浸泡和蒸煮加工前处理过程中，芦丁和槲皮素存在着相互转化现象。本项目拟利用现代化植化提取纯化、聚丙烯凝胶电泳和质谱分析等技术方法，分离纯化鉴定在芦丁、槲皮素相互转化反应中起关键作用的酶，黄酮醇3-葡萄糖苷酶、3-O-葡萄糖基转移酶、鼠李糖基转移酶；分析生物学特性；研究浸泡和蒸煮过程中酶的活性变化，分析酶活性变化与和芦丁、槲皮素含量变化相关性；阐明加工前处理对苦荞籽粒中芦丁和槲皮素相互转化的响应机理，探索建立苦荞加工过程中人工调控芦丁和槲皮素转化反应的技术方法；为研发功能活性更强的苦荞茶及其他苦荞食品提供理论依据和技术支撑。

苦荞麦，学名鞑靼荞麦，是中国特有的药食兼用粮食作物，世界上90%以上的苦荞产于中国。黄酮类化合物是苦荞中最重要的生物活性物质之一被广泛研究，其中芦丁含量最高，此外还含少量功能活性更强的槲皮素和异槲皮素。本项目拟阐明加工前处理对苦荞籽粒中芦丁和槲皮素相互转化的响应机理，探索建立苦荞加工过程中人工调控芦丁和槲皮素转化反应的技术方法。研究中发现苦荞茶加工前处理过程中浸泡处理，芦丁发生水解反应转化形成槲皮素。而高温蒸煮过程中又发生了可逆转化反应，即槲皮素重新转化生成芦丁。但在随后对调控芦丁和槲皮素相互转化反应的3个关键酶进行提取分离纯化提取时，未得到较为满意的结果。为此将研究内容调整为苦荞发芽过程中黄酮类化合物、多酚、D-手性肌醇等功能因子含量及其功能活性变化研究和荞麦麸皮活性蛋白提取分离工艺研发及活性评价研究：发现利用低浓度的小苏打溶液刺激荞麦发芽，能显著提高荞麦芽中总多酚、总黄酮、芦丁、槲皮素、异槲皮素、山奈酚、D-手性肌醇等功能成分的含量，特别是D-手性肌醇含量呈倍数增长，其抗氧化活性和ɑ-葡萄糖苷酶抑制活性也随之提高，为高营养保健活性荞麦芽菜研发提供技术支撑。研究发现通过生物酶解，麸皮蛋白提取率由71.3%提高至87.7%，且抗氧化活性显著提高，ɑ-葡萄糖苷酶抑制活性提高2.7倍。