The aim of this study was to determine the influence of heat processing on denaturation and digestibility properties of protein isolates obtained from sweet quinoa (Chenopodium quinoa Willd) at various extraction pH values (8, 9, 10 and 11). Pretreatment of suspensions of protein isolates at 60, 90 and 120 °C for 30 min led to protein denaturation and aggregation, which was enhanced at higher treatment temperatures. The in vitro gastric digestibility measured during 6 h was lower for protein extracts pre-treated at 90 and 120 °C compared to 60 °C. The digestibility decreased with increasing extraction pH, which could be ascribed to protein aggregation. Protein digestibility of the quinoa protein isolates was higher compared to wholemeal quinoa flour. We conclude that an interactive effect of processing temperature and extraction pH on in vitro gastric digestibility of quinoa protein isolates obtained at various extraction pH is observed. This gives a first indication of how the nutritional value of quinoa protein could be influenced by heat processing, protein extraction conditions and other grain components.

中文翻译：

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在各种提取pH下获得的热处理藜麦分离蛋白的变性和体外胃液消化。

这项研究的目的是确定热处理对甜藜麦（Chenopodium quinoa）分离蛋白的变性和消化特性的影响。Willd）在各种萃取pH值（8、9、10和11）下。分别在60、90和120°C下对蛋白质分离物的悬浮液进行30分钟的预处理，导致蛋白质变性和聚集，在更高的处理温度下会增强。与60°C相比，在90和120°C预处理的蛋白质提取物在6小时内测得的体外胃消化率较低。消化率随提取pH的升高而降低，这可能归因于蛋白质聚集。与全麦藜麦粉相比，藜麦分离蛋白的蛋白质消化率更高。我们得出的结论是，观察到加工温度和提取pH对在各种提取pH下获得的藜麦分离蛋白的体外胃消化率的相互作用。