不同种类糖对燕麦蛋白糖基化产物 功能性质及结构的影响Effects of different sugars on functional properties and structure of oat protein glycosylation products

为提高燕麦蛋白（OP）的功能性质，提高其品质,分别采用葡萄糖(G)、乳糖(L)、壳寡糖(C)、海藻酸钠(S)对燕麦蛋白进行湿法糖基化改性，探究4种不同分子大小的糖对燕麦蛋白糖基化产物（G-OP、L-OP、C-OP、S-OP）功能性质及结构的影响。结果表明：4种糖基化燕麦蛋白的溶解性较改性前均有较大提高，其中L-OP的溶解度（pH 7）较改性前提高了64.23百分点；4种糖基化燕麦蛋白的乳化活性指数（EAI）和乳化稳定性指数(ESI)均显著提高（p＜ 0.05），其中C-OP的EAI和ESI较改性前分别增加了8.91 m2/g和21.26百分点；4种糖基化燕麦蛋白的持水性、吸油性、体外消化性及表面疏水性较改性前均显著提高（p＜ 0.05）；SDS-PAGE、傅里叶红外光谱、荧光光谱分析表明，糖链的引入使OP空间结构发生了变化，证明了OP分别与4种糖发生共价结合生成糖蛋白。综上，虽然蛋白的糖基化反应是一种化学改性，但由于没有任何化学试剂参与，通过自发反应发生共价交联，生成具有良好功能性质的蛋白糖基化共价复合物，属于“绿色加工工艺”，适合高品质改性植物蛋白的研制。 In order to improve the functional properties of oat protein (OP) and improve its quality, OP was modified by wet glycosylation with glucose(G), lactose(L), chitosan(C) and sodium alginate(S) respectively to explore the effects of four sugars of different molecular masses on the functional properties and structure of oat protein glycosylation products (G-OP，L-OP，C-OP，S-OP).The results showed that the solubility of the four glycosylated oat proteins was greatly improved, and the solubility (pH 7) of L-OP increased by 64.23 percentage points compared with that without modification.The emulsifying activity index(EAI) and emulsifying stability index(ESI) of the four glycosylated oat proteins were significantly improved (p＜ 0.05), in which the EAI and ESI of C-OP increased by 8.91 m2/g and 21.26 percentage points respectively compared with those before modification.The water holding capacity, oil absorption, in vitro digestibility and surface hydrophobicity of the four glycosylated oat proteins were significantly improved (p＜ 0.05) compared with OP. SDS-PAGE, Fourier infrared spectroscopy and fluorescence spectrum analysis showed that the introduction of sugar chains changed the spatial structure of OP, further proving that OP covalently bound four sugars and formed glycoproteins.In summary, although the glycosylation reaction of protein is a kind of chemical modification, covalent cross-linking occurs through spontaneous reaction without the participation of any chemical reagent to produce covalent protein glycosylation complexes with good functional properties, which belongs to the "green processing technology", and is suitable for the development of high-quality modified plant proteins.