pH-dependent emulsifying properties of pea [Pisum sativum (L.)] proteins
pH-dependent emulsifying properties of pea [Pisum sativum (L.)] proteins
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豌豆 [Pisum sativum (L.)] 蛋白质的 pH 依赖性乳化特性
DOI：
10.1016/j.foodhyd.2013.04.005
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发表时间：
2013-12-01
影响因子：
10.7
通讯作者：
Tang, Chuan-He
中科院分区：
文献类型：
--
作者：
Liang, Han-Ni;Tang, Chuan-He
以干豌豆种子为原料，研究了不同pH值（3.0、5.0、7.0和9.0）下两种部分纯化的豆科蛋白和维西林（PL和PV）以及分离蛋白（PPI）的乳化特性。测试的乳液特性包括液滴大小、絮凝和聚结指数（FI和CI）、成乳指数以及界面蛋白质吸附。对这些蛋白质的一些理化性质，如游离巯基和二硫键含量、蛋白质溶解度（PS）、表面疏水性（H-o）和热稳定性（和变性）进行了表征。结果表明，各种豌豆蛋白的乳化能力和乳化稳定性随制备工艺、蛋白质组成和pH值的不同而有较大差异。总体而言，所有豌豆蛋白在pH 5.0（等电点附近）时的乳化能力最低，同时所制得的乳液最不稳定，不容易聚结和成乳。这些蛋白在pH值为3.0时的乳化能力普遍优于在中性或碱性pH值下的乳化能力，其中PL在该pH值下的乳化能力最高。新鲜乳剂中的絮凝状态和液滴大小并不直接影响这些乳剂的抗絮凝和聚结稳定性（储存24 h），甚至是乳化性（长达7天）。有趣的是，当pH偏离pI时，PL和PV表现出比PPI更好的乳化稳定性。这些蛋白的乳化特性不仅与它们的PS和Ho有关，还与界面蛋白膜的蛋白质吸附性质（如粘弹性）有关。这些结果可以极大地扩展对豌豆蛋白乳化特性的认识，特别是对乳液特性的pH依赖性。(C) 2013 Elsevier Ltd.版权所有。
Emulsifying properties of two partially purified legumin and vicilin (PL and PV) and protein isolate (PPI) from dry pea seeds at various pH values (3.0, 5.0, 7.0 and 9.0) were investigated. The tested emulsion characteristics included droplet size, flocculation and coalescence indices (FI and CI), creaming index, as well as interfacial protein adsorption. Some physicochemical properties of these proteins, e.g., free sulfhydryl and disulfide bond contents, protein solubility (PS), surface hydrophobicity (H-o) and thermal stability (and denaturation), were also characterized. The results indicated that emulsifying ability and emulsion stability of various pea proteins considerably varied with the preparation process, protein composition and pH. Overall, all the pea proteins exhibited least emulsifying ability at pH 5.0 (around isoelectric point), and concomitantly, the resultant emulsions were most unstable against coalescence and creaming. The emulsifying ability of these proteins at pH 3.0 was generally better than that at neutral or alkali pH values, and among all the three proteins, PL exhibited highest emulsifying ability at this pH. The flocculated state and size of droplets in fresh emulsions did not directly affect stability of these emulsions against flocculation and coalescence (upon 24 h of storage), and even creaming (up to 7 days). Interestingly, the PL and PV exhibited much better creaming stability than PPI, at pH deviating from the pI. The emulsifying properties of these proteins were not only related to their PS and Ho, but also associated with the protein adsorption and nature (e.g., viscoelasticity) of interfacial protein films. These results can greatly extend the knowledge for understanding the emulsifying properties of pea proteins, especially the pH dependence of emulsion characteristics. (C) 2013 Elsevier Ltd. All rights reserved.