Abstract High-performance foaming agents are widely required in the food industry. In this study, the relationship between electrostatic interaction of whey protein isolate (WPI)/sodium alginate (ALG) and the resultant foaming properties were investigated systematically. The phase diagram of WPI/ALG was established in terms of protein/polysaccharide mixing ratio (r) and pH. The results show that the foaming capacity of WPI/ALG complexes is almost the same across different regions of the phase diagram, while the foam stability varies significantly. At pHs 7.0 and 0.5 where no electrostatic complexation occurs, the foam stability is found to decrease monotonically with decreasing r. At pH 4.0 and particular mixing ratios, i.e., r = 1 and 2, intramolecular soluble complexes are formed and the particular WPI/ALG complexes yield the best foam stability, as compared to other electrostatic complexes or individual components. The half-life (t1/2) of the foams stabilized by the intramolecular electrostatic complexes is as long as 4000 s at a very low WPI/ALG concentration of 0.1% w/w. The foaming properties are in line with the foam viscosity, interfacial adsorption behavior and microstructures of the complexes observed at the air-water interface. This demonstrates that the protein/polysaccharide intramolecular electrostatic complex, more specifically at the stoichiometry, could potentially act as a superior foaming agent in the food industry.

中文翻译：

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作为优质食品级发泡剂的蛋白质/多糖分子内静电复合物

摘要 食品工业广泛需要高性能发泡剂。在这项研究中，系统地研究了乳清蛋白分离物 (WPI)/海藻酸钠 (ALG) 的静电相互作用与由此产生的发泡特性之间的关系。WPI/ALG 的相图是根据蛋白质/多糖混合比 (r) 和 pH 值建立的。结果表明，WPI/ALG复合物在相图不同区域的发泡能力几乎相同，而泡沫稳定性差异显着。在没有发生静电络合的 pH 值为 7.0 和 0.5 时，发现泡沫稳定性随着 r 的降低而单调降低。在 pH 4.0 和特定混合比，即 r = 1 和 2 下，形成分子内可溶性复合物，特定的 WPI/ALG 复合物产生最佳泡沫稳定性，与其他静电复合物或单个组件相比。在 0.1% w/w 的非常低的 WPI/ALG 浓度下，由分子内静电复合物稳定的泡沫的半衰期 (t1/2) 长达 4000 秒。发泡性能与在空气-水界面观察到的复合物的泡沫粘度、界面吸附行为和微观结构一致。这表明蛋白质/多糖分子内静电复合物，更具体地说，在化学计量方面，有可能在食品工业中充当优良的发泡剂。发泡性能与在空气-水界面观察到的复合物的泡沫粘度、界面吸附行为和微观结构一致。这表明蛋白质/多糖分子内静电复合物，更具体地说，在化学计量方面，有可能在食品工业中充当优良的发泡剂。发泡性能与在空气-水界面观察到的复合物的泡沫粘度、界面吸附行为和微观结构一致。这表明蛋白质/多糖分子内静电复合物，更具体地说，在化学计量方面，有可能在食品工业中充当优良的发泡剂。