Department of Food Science, University of Wisconsin-Madison, 1605 Linden Drive, Madison, Wisconsin 53706-1565, USA.
J Agric Food Chem. 2010 Mar 10;58(5):2988-94. doi: 10.1021/jf903643p.
The physicochemical and emulsifying properties of protein and polysaccharide conjugates prepared under mild conditions were investigated. The covalently linked conjugates of whey protein isolate (WPI) and dextran (DX, 440 kDa) were produced by incubating aqueous solutions containing 10% WPI and 30% DX at pH 6.5 and 60 degrees C for 48 h. After purification by anion-exchange chromatography and affinity chromatography, the conjugate had a weight-average molecular weight (M(w)) of 531 kDa and a radius of gyration (R(g)) of 30 nm as determined by size exclusion chromatography-multiangle laser light scattering (SEC-MALLS); the molar binding ratio of WPI to DX was calculated to be approximately 1:1. The purified conjugate had significantly improved heat stability when subjected to 80 degrees C for 30 min and remained soluble over a range of pH from 3.2 to 7.5 and ionic strengths from 0.05 to 0.2 M in contrast to native WPI. The emulsifying ability and emulsion stability made with WPI-DX conjugate were also improved compared to WPI and gum arabic (an emulsifier containing naturally derived glycoproteins).
研究了在温和条件下制备的蛋白质-多糖缀合物的物理化学和乳化性质。通过在 pH 值为 6.5 和 60°C 下孵育含有 10% WPI 和 30% DX 的水溶液 48 小时，制备了乳清蛋白分离物（WPI）和葡聚糖（DX，440 kDa）的共价连接缀合物。通过阴离子交换色谱和亲和色谱纯化后，缀合物的重均分子量（Mw）为 531 kDa，回转半径（Rg）为 30nm，通过尺寸排阻色谱-多角度激光光散射（SEC-MALLS）测定；WPI 与 DX 的摩尔结合比计算约为 1:1。与天然 WPI 相比，经 80°C 加热 30 分钟后，纯化的缀合物具有显著提高的热稳定性，在 pH 值为 3.2 至 7.5 且离子强度为 0.05 至 0.2 M 的范围内保持可溶性。与 WPI 和阿拉伯胶（一种含有天然衍生糖蛋白的乳化剂）相比，用 WPI-DX 缀合物制备的乳化能力和乳液稳定性也得到了提高。
