No abstract

-The objective of this study was to evaluate the influence of high-pressure treatments on the solubility, surface hydrophobicity, foaming and emulsifying ability of whey protein concentrate (WPC) and whey protein isolate (WPI). Dispersions of WPC and WPI powders (10% (w/w)) were processed at 300 MPa and 600 MPa, for 5 and 10 min at 40 ± 2°C. Changes in protein solubility were determined as solubility at pH 7.0 and at pH 4.6. Assessment of foaming properties was based on the foam expansion during prolonged whipping, and foam stability. Emulsifying properties were characterised by emulsion stability and emulsifying activity indices. The results show significant (P < 0.05) modification of solubility and surface hydrophobicity with increasing intensity and duration of applied pressure, indicating partial denaturation and aggregation of proteins. It was found that high-pressure treatments significantly (P < 0.05) improved the foaming behaviour of WPI, while the foaming ability of WPC was diminished. However, foams formed with high-pressuretreated WPC and WPI exhibited significantly prolonged stability (P < 0.05) compared with control samples. There was a significant trend of decreasing emulsifying efficiency and emulsifying stability related to the intensity of applied pressure and treatment time for both WPC and WPI. emulsifying properties / foaming properties / high pressure / whey protein concentrate / whey protein isolate / solubility / surface hydrophobicity 摘要 -高压处理对乳清浓缩蛋白和乳清分离蛋白的影响。本文研究了高压处理对乳清浓缩 蛋白 (WPC) 和乳清分离蛋白 (WPI) 的溶解性、表面疏水性、发泡性和乳化性的影响。在 40°C 下，乳清浓缩蛋白 (10 %, w/w) 和乳清分离蛋白 (10 %, w/w) 的分散液分别在 300 MPa 和 600 Mpa 下高压处理 5 min 和 10 min。在 pH 7.0 和 pH 4.6 测定了两种蛋白质溶解性的变 化。以长时间搅打后形成的泡沫膨胀度和泡沫稳定性来评价蛋白质的发泡性能；根据测定 乳液稳定性指数和乳化活性指数评价两种蛋白质的乳化特性。试验结果表明，经过高压长 时间的处理后，由于蛋白质发生了部分变性和凝聚作用，使得蛋白质的溶解性和表面疏水 性发生了显著的改变 (P < 0.05)。高压处理能够显著地改善 WPI 的发泡性 (P < 0.05)，而 WPC 的泡沫形成能力则降低。然而与对照样品相比，经过高压处理后的 WPC 和 WPI 形成的泡 沫稳定性有显著提高 (P < 0.05)。随着处理压力和作用时间的增加，两种蛋白质的乳化性和 乳化稳定性均呈下降的趋势。 乳化性 / 发泡性 / 高压 / 乳清浓缩蛋白 / 乳清分离蛋白 / 溶解性 / 表面疏水性 * Corresponding author (通讯作者): Greta.Kresic@fthm.hrArticle published by EDP Sciences and available at http://www.edpsciences.org/lait or http://dx

No abstract

No abstract

No abstract