Ruiz Geraldine Avila, Xiao Wukai, van Boekel Martinus, Minor Marcel, Stieger Markus
Food and Biobased Research, Wageningen University and Research Centre, P.O. Box 17, 6700 AA Wageningen, Netherlands.
Food Quality and Design Group, Wageningen University and Research Centre, P.O. Box 9101, 6700 HB Wageningen, Netherlands.
Food Chem. 2016 Oct 15;209:203-10. doi: 10.1016/j.foodchem.2016.04.052. Epub 2016 Apr 18.
The aim of this study was to determine the influence of extraction pH on heat-induced aggregation, gelation and microstructure of suspensions of protein isolates extracted from quinoa (Chenopodium quinoa Willd). Quinoa seed protein was extracted by alkaline treatment at various pH values (pH 8 (E8), 9 (E9), 10 (E10) and 11 (E11)), followed by acid precipitation. The obtained protein isolates were freeze dried. The protein isolates E8 and E9 resulted in a lower protein yield as well as less protein denaturation. These isolates also had a higher protein purity, more protein bands at higher molecular weights, and a higher protein solubility in the pH range of 3-4.5, compared to the isolates E10 and E11. Heating the 10%w/w protein isolate suspensions E8 and E9 led to increased aggregation, and semi-solid gels with a dense microstructure were formed. The isolate suspensions E10 and E11, on the other hand, aggregated less, did not form self-supporting gels and had loose particle arrangements. We conclude that extraction pH plays an important role in determining the functionality of quinoa protein isolates.
本研究的目的是确定提取pH值对从藜麦（Chenopodium quinoa Willd）中提取的蛋白质分离物悬浮液的热诱导聚集、凝胶化和微观结构的影响。通过在不同pH值（pH 8（E8）、9（E9）、10（E10）和11（E11））下进行碱性处理，随后进行酸沉淀来提取藜麦种子蛋白。将获得的蛋白质分离物冷冻干燥。蛋白质分离物E8和E9的蛋白质产量较低，蛋白质变性也较少。与分离物E10和E11相比，这些分离物还具有更高的蛋白质纯度、更高分子量处更多的蛋白条带，以及在3 - 4.5的pH范围内更高的蛋白质溶解度。加热10%w/w的蛋白质分离物悬浮液E8和E9会导致聚集增加，并形成具有致密微观结构的半固体凝胶。另一方面，分离物悬浮液E10和E11的聚集较少，没有形成自支撑凝胶，且颗粒排列松散。我们得出结论，提取pH值在决定藜麦蛋白质分离物的功能方面起着重要作用。
