EMULSIFYING PROPERTIES OF COVALENT PROTEIN DEXTRAN HYBRIDS
EMULSIFYING PROPERTIES OF COVALENT PROTEIN DEXTRAN HYBRIDS
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DOI：
10.1016/0166-6622(92)80109-f
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发表时间：
1992-07-09
期刊：
影响因子：
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通讯作者：
SEMENOVA, MG
中科院分区：
文献类型：
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作者：
DICKINSON, E;SEMENOVA, MG
本文研究了非离子多糖葡聚糖与三种蛋白质(11S球蛋白蚕豆蛋白、牛血清白蛋白、β-酪蛋白)共价美拉德络合物的乳化行为与葡聚糖分子量的关系。10(4)或5。10(5)Da)和多糖/蛋白质摩尔比R.蛋白质-多糖杂交物是由蛋白质和葡聚糖在60℃下干热3周制成的。水包油乳剂(10体积%正十四烷，0.5%蛋白质，pH 8，离子强度0.1M)含有不同比例的多糖，以Maillard络合物或与蛋白质的简单混合物形式存在，监测液滴尺寸分布和血清层厚度作为储存时间的函数。结果表明，葡聚糖与球蛋白(牛血清白蛋白和11S球蛋白)的共价结合可显著改善乳化性，而与无序蛋白β-酪蛋白的络合作用则不起作用。与11S球蛋白相比，球蛋白-葡聚糖杂化的乳状液一般要细得多，11S球蛋白是一种相当差的乳化剂。对于每种蛋白质，乳化能力和乳化稳定性对葡聚糖的相对分子质量和R都很敏感，而且对于每种蛋白质-多糖组合，似乎都有一个提供最佳稳定性的临界值。蛋白质与葡聚糖的反应时间超过必要的时间(尤其是高分子量的)会导致功能丧失，就像未被吸附的(未反应的)多糖的存在一样。球状蛋白与多糖络合后乳化性能提高的主要原因是大体积亲水多糖部分提供了增强的空间稳定性。由于吸附的球蛋白-葡聚糖杂化蛋白的表面剪切粘度与单独吸附的天然蛋白的表面剪切粘度仅略有不同，因此，吸附层中的蛋白质-蛋白质相互作用似乎相对不受络合的影响。
The emulsifying behaviour of covalent Maillard complexes of the non-ionic polysaccharide dextran with three proteins (11S globulin Vicia faba, bovine serum albumin, beta-casein) has been investigated as a function of the molecular weight of the dextran (4 . 10(4) or 5 . 10(5) Da) and the polysaccharide/protein molar ratio R. Protein-polysaccharide hybrids are made by dry-heating mixtures of protein and dextran at 60-degrees-C for (usually) 3 weeks. The droplet-size distribution and serum layer thickness are monitored as a function of storage time for oil-in-water emulsions (10 vol.% n-tetradecane, 0.5 wt.% protein, pH 8, ionic strength 0.1 M) containing various proportions of polysaccharide, present either as a Maillard complex or in a simple admixture with the protein. The results show that covalent binding of dextran to the globular proteins (bovine serum albumin and 11S globulin) can lead to a substantial improvement in the emulsifying behaviour, whereas complexation with the disordered protein beta-casein has a negative effect. The globulin-dextran hybrids generally give much finer emulsions than the 11S globulin alone which is a rather poor emulsifying agent. For each protein, the emulsifying capacity and emulsion stability are sensitive to dextran molecular weight and R, and it appears that for each protein-polysaccharide combination there is a critical value of R which confers the optimum stabilization. Reaction of protein with dextran for longer than is necessary (especially that of high molecular weight) leads to loss of functionality, as does the presence of unadsorbed (unreacted) polysaccharide. The primary single reason for the improved emulsifying properties of globular proteins on complexing with polysaccharide is the enhanced steric stabilization provided by the bulky hydrophilic polysaccharide moiety. As the measured surface shear viscosity of the adsorbed globulin-dextran hybrid is only slightly different from that of the adsorbed native protein alone, it appears that the protein-protein interactions in thc adsorbed layer are relatively unaffected by the complexation.