Nasrabadi Maryam Nikbakht, Eskin Michael N A, Thiyam-Hollander Usha, Ghosh Supratim
Department of Food and Bioproduct Sciences, College of Agriculture and Bioresources, University of Saskatchewan 51 Campus Drive Saskatoon SK S7N 5A8 Canada
Department of Food and Human Nutritional Sciences, University of Manitoba 35 Chancellor's Circle Winnipeg MN Canada.
RSC Adv. 2025 Jun 3;15(23):18430-18443. doi: 10.1039/d4ra06899h. eCollection 2025 May 29.
This study explores the use of an acidic water-soluble fraction of pea protein as an effective plant-based emulsifier for stabilizing low-pH oil-in-water emulsions. Mildly fractionated soluble pea protein (containing 2.5 wt% protein), recovered by centrifuging pea protein concentrate dispersion at pH 2.0, was directly used to prepare a 5 wt% canola oil-in-water emulsion using a high-pressure homogenizer. Emulsion stability was evaluated at pH 2.0 for 28 days at room temperature as well as against environmental stress conditions, including heat treatment (90 °C, 30 min) in the presence and absence of NaCl (0-1 M). The results showed that the acidic water-soluble pea protein, rich in albumins, exhibited excellent emulsifying properties and improved thermal stability, showing minor changes in droplet size until day 28, even after heat treatment. We proposed that such improved emulsion thermal stability under acidic conditions could be due to the high albumin content, lower surface hydrophobicity and higher β-sheet and random coil secondary structure content of the acidic-soluble fraction compared to the whole pea protein pH 7.0 extracts. However, the emulsions were unstable against high salt concentrations (0.5 and 1 M NaCl), showing extensive aggregation worsened by heating, which was attributed to the charge screening effect of salt and unfavourable conformational change in the albumin-rich proteins. The novel findings of this study can provide essential knowledge and set the stage for the development of pea protein ingredients ideal for utilization in ready-to-drink acidic plant-based beverages.
本研究探索了豌豆蛋白的酸性水溶性组分作为一种有效的植物基乳化剂用于稳定低pH值水包油乳液的情况。通过在pH 2.0下离心豌豆蛋白浓缩物分散液回收的轻度分级分离的可溶性豌豆蛋白（含2.5 wt%蛋白质），直接用于使用高压均质机制备5 wt%的菜籽油水包油乳液。在室温下于pH 2.0条件下对乳液稳定性进行了28天的评估，以及评估其在包括有和没有NaCl（0 - 1 M）存在下的热处理（90 °C，30分钟）等环境应激条件下的稳定性。结果表明，富含白蛋白的酸性水溶性豌豆蛋白表现出优异的乳化性能并提高了热稳定性，直到第28天液滴尺寸变化很小，即使经过热处理也是如此。我们认为，在酸性条件下乳液热稳定性的这种提高可能归因于与整个豌豆蛋白pH 7.0提取物相比，酸性可溶级分中白蛋白含量高、表面疏水性低以及β-折叠和无规卷曲二级结构含量高。然而，乳液在高盐浓度（0.5和1 M NaCl）下不稳定，加热会使其聚集加剧，这归因于盐的电荷屏蔽效应以及富含白蛋白的蛋白质中不利的构象变化。本研究的新发现可为开发适用于即饮型酸性植物基饮料的豌豆蛋白成分提供必要的知识并奠定基础。
