College of Biosystems Engineering and Food Science, National-Local Joint Engineering Laboratory of Intelligent Food Technology and Equipment, Zhejiang Key Laboratory for Agro-Food Processing, Zhejiang R & D Center for Food Technology and Equipment, Zhejiang University, Hangzhou 310058, China; Teagasc Food Research Centre, Moorepark, Fermoy, Co. Cork, Ireland.
College of Biosystems Engineering and Food Science, National-Local Joint Engineering Laboratory of Intelligent Food Technology and Equipment, Zhejiang Key Laboratory for Agro-Food Processing, Zhejiang R & D Center for Food Technology and Equipment, Zhejiang University, Hangzhou 310058, China.
Food Chem. 2020 Mar 30;309:125501. doi: 10.1016/j.foodchem.2019.125501. Epub 2019 Sep 7.
In this study, we selected two most commonly-available commercial pectin, i.e. citrus pectin and apple pectin as the grafting polysaccharides to prepare soy protein isolate-pectin conjugates. Despite the similar degrees of methoxylation and acetylation for two pectin samples, apple pectin showed much more complex structures compared to citrus pectin, with a 2.20-fold higher molecular weight and large numbers of side chains. The conjugates were prepared under controlled dry-heating conditions and achieved the degree of graft of 25.00% and 21.85% for citrus and apple pectin, respectively. Formation of the conjugates was further confirmed by SDS-PAGE gel electrophoresis and IR spectra. Attributed to the strong steric-hindrance effect of pectin, the fluorescence intensity and surface hydrophobicity of the soy protein isolate were significantly decreased after Maillard reaction. However, both solubility and emulsifying properties of the conjugates were significantly improved. Results indicated that both pectin samples played favorable roles in protein modification.
在这项研究中，我们选择了两种最常用的商业果胶，即柑橘果胶和苹果果胶，作为接枝多糖来制备大豆分离蛋白-果胶共轭物。尽管两种果胶样品的甲氧基化和乙酰化程度相似，但与柑橘果胶相比，苹果果胶的结构更为复杂，分子量高 2.20 倍，且具有大量的侧链。在控制的干热条件下制备了这些共轭物，其接枝程度分别为 25.00%和 21.85%。SDS-PAGE 凝胶电泳和 IR 光谱进一步证实了共轭物的形成。由于果胶的强大空间位阻效应，在美拉德反应后，大豆分离蛋白的荧光强度和表面疏水性显著降低。然而，共轭物的溶解度和乳化性能都得到了显著提高。结果表明，两种果胶样品在蛋白质改性中都发挥了良好的作用。
