Department of Chemical Engineering, Federal University of Paraná, Rua Francisco H. dos Santos s/n, Zip Code 81531-980 Curitiba, PR, Brazil.
Department of Biochemistry, State University of Maringá, Av. Colombo 5790, Zip Code 87020-900 Maringá, PR, Brazil.
Food Chem. 2017 Oct 1;232:263-271. doi: 10.1016/j.foodchem.2017.04.014. Epub 2017 Apr 5.
This work aimed to study the influence of pH (3.5 and 7.0) and CaCl and MgCl addition on heat-set gelation of a quinoa protein isolate at 10% and 15% (w/w). The protein isolate obtained was composed mainly of 11S globulin as was observed by electrophoresis and mass spectrometry analysis. Heat-set gelation occurred at both pH values studied. Nevertheless, the gels formed at pH 3.5 were more viscoelastic and denser than those formed at pH 7.0, that was coarser and presented syneresis. The CaCl and MgCl addition increased the gel strength during rheological analysis at pH 3.5, possibly due to the formation of fiber-like connections in the gel network. At pH 7.0, the divalent salts resulted in weaker gels formed by agglomerates, suggesting a neutralization of the protein surface charges. The differences in quinoa protein gelation were attributed to solubility, and the flexibility of proteins secondary structure at the pH studied.
本研究旨在探讨 pH 值（3.5 和 7.0）和添加 CaCl₂ 和 MgCl₂对在 10%和 15%（w/w）条件下热凝的藜麦蛋白分离物的影响。电泳和质谱分析表明，所得到的蛋白分离物主要由 11S 球蛋白组成。在两种研究的 pH 值下均发生了热凝。然而，在 pH 3.5 下形成的凝胶比在 pH 7.0 下形成的凝胶更具有粘弹性和密度，后者更粗糙并呈现出离浆现象。在 pH 3.5 时，添加 CaCl₂ 和 MgCl₂增加了凝胶的强度，这可能是由于在凝胶网络中形成了纤维状连接。在 pH 7.0 时，二价盐导致通过团聚体形成较弱的凝胶，表明蛋白质表面电荷被中和。藜麦蛋白凝胶形成的差异归因于在研究 pH 值下的蛋白质溶解度和二级结构的灵活性。
