乳清蛋白-大米淀粉混合体系动态流变学特性研究

Study on Dynamic Rheological Properties of Whey Protein-Rice Starch Hybrid System

乳清蛋白和淀粉因其较好的凝胶形成特性而被广泛用于食品配料。通过动态流变仪研究乳清蛋白-大米淀粉混合体系的动态流变性,并同时考虑了离子及离子强度对流变特性的影响。结果表明,在淀粉比例低于50%时,乳清蛋白-大米淀粉混合体系升温过程的储能模量(G')和损耗模量(G")明显低于乳清蛋白,而当淀粉比例升至50%时,最终的G'和G"已经远远超过乳清蛋白;此外,降温过程中混合体系的最终G'和G"也远高于乳清蛋白,表明蛋白质淀粉分子间的相互作用的增强对混合凝胶的特性有一定的协效性,强化了形成的凝胶网络。随着盐离子浓度的提高,混合体系的G'和G"均持续降低,表明盐离子和蛋白质分子间的相互作用一定程度上阻碍了淀粉与蛋白质分子间的相互作用,弱化了形成的凝胶网络。

Whey protein and starches have been widely used as food ingredients owing to their good gelation properties. Dynamic rheological properties of whey protein - rice starch hybrid system were investigated in this study using dynamic rheometer, and meanwhile the effects of different ions and ionic strength on rheological properties are also considered. The results showed that when starch concentration was lower than 50%, both storage modulus （ G＇ ） and loss modulus （G＂） of mixed gel during heating were lower than those of whey protein. However, when starch concentration reached 50%, the final G＇ and G＂ values were much higher than those of whey protein. Furthermore, the final G＇ and G＂ values of all mixed gels during cooling process are also much higher than those of whey protein. It is indicated that the enhanced interactions between protein and starch molecules has certain synergistic effects on characteristics of mixed gel, and strengthens the formed gel network. With the increase of salt concentration, both G＇ and G＂ of hybrid gel were continuously decreased, suggesting that the interactions between salt ions and protein mole- cules hinder the interactions between starch and protein molecules, and thus weaken the formed gel network.