油菜籽中单宁的提取、组成及性质的研究

Study on the Tannins in Rapeseed

油菜粕中单宁最佳提取条件为７０％的丙酮水，温度３０℃，粒度５０目。提取率８３％。菜粒中硫代葡萄糖甙只残留６．４７μｍｏ１／ｇ，植酸几乎没有被提取。菜籽单宁是含有水解单宁和缩合单宁的混合型单宁。分子量范围在１３００～２９００之间。是无色氰定的４～８聚体。单宁结合有葡萄糖、果糖、鼠李糖和蛋白质。结合蛋白质富含脯氨酸，有较高的疏水参数值。研究了ｐＨ值、重金属离子、离子强度、温度等因素对菜籽单宁－蛋白质复合物形成的影响。

The extraction,purification condition,structure and characteristics of tannin in rapeseed investigated.Defatted rapeseed meal (50 mesh) extracted with 70% acetone water solution at 30℃ was the optimum tannin extraction condition.Glucosinolate remained 6.467μmo1/g in the oil meal,phytic acid almost no exacted during the process.The molecular weights of the tannins were from 1300 to 2900,they may be considered as a leucocyanidin oligomers with the degree of polymerization of 4～8.Rapeseed oilmeal contained hydrolyzable and condensed tannin,associated with glucose,fructose and protein.Tannin binded tighly to proline-rich protein,and the binded protein had more non polar side than free protein did.The study showed that pH value played an important role in the interaction.Tannin-protein complexes are normally established by hydrogen bonds and hydrophobic interaction.Tannin acts as a hydrogen bond donor,the carbonyl oxygen of the peptide bond presumably serves as the hydrogen bond acceptor.pH can affect the form of tannin,so it can affect the formation of hydrogen bonds.Neutral ion intensity had an effect on the complexation in a certain degree.Heavy metal ions also influenced the interaction strongly. Metal ions sequestrated with tannin and also associated with protein, forming a new complex.Temperature showed little effect on the interaction.