Riedel Laura, Leister Nico, van der Schaaf Ulrike S
Institute of Process Engineering in Life Sciences-Food Process Engineering, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany.
Foods. 2025 Jul 28;14(15):2643. doi: 10.3390/foods14152643.
In the search for alternative protein sources, single cell proteins have gained increasing attention in recent years. Among them, proteins derived from yeast represent a promising but still underexplored option. To enable their application in food product design, their techno-functional properties must be understood. In order to investigate the impact of precipitation pH on their emulsion-stabilizing properties, yeast proteins from were isolated via precipitation at different pH (pH 3.5 to 5) after cell disruption in the high-pressure homogenizer. Emulsions containing 5 wt% oil and ~1 wt% protein were analyzed for stability based on their droplet size distribution. Proteins precipitated at pH 3.5 stabilized the smallest oil droplets and prevented partitioning of the emulsion, outperforming proteins precipitated at higher pH values. It is hypothesized that precipitation under acidic conditions induces protein denaturation and thereby exposes hydrophobic regions that enhance adsorption at the oil-water interface and the stabilization of the dispersed oil phase. To investigate the stabilization mechanism, the molecular weight of the proteins was determined using SDS-PAGE, their solubility using Bradford assay, and their aggregation behavior using static laser scattering. Proteins precipitated at pH 3.5 possessed larger molecular weights, lower solubility, and a strong tendency to aggregate. Overall, the findings highlight the potential of yeast-derived proteins as bio-surfactants and suggest that pH-controlled precipitation can tailor their functionality in food formulations.
在寻找替代蛋白质来源的过程中，单细胞蛋白近年来越来越受到关注。其中，源自酵母的蛋白质是一个有前景但仍未得到充分探索的选择。为了使其能够应用于食品产品设计，必须了解它们的技术功能特性。为了研究沉淀pH值对其乳化稳定性能的影响，在高压均质机中细胞破碎后，通过在不同pH值（pH 3.5至5）下沉淀从[具体来源未提及]中分离出酵母蛋白。基于液滴尺寸分布分析了含有5 wt%油和~1 wt%蛋白质的乳液的稳定性。在pH 3.5下沉淀的蛋白质稳定了最小的油滴，并防止了乳液的分层，其性能优于在较高pH值下沉淀的蛋白质。据推测，酸性条件下的沉淀会诱导蛋白质变性，从而暴露出疏水区域，增强在油水界面的吸附以及分散油相的稳定性。为了研究稳定机制，使用SDS-PAGE测定蛋白质的分子量，使用Bradford测定法测定其溶解度，并使用静态激光散射测定其聚集行为。在pH 3.5下沉淀的蛋白质具有更大的分子量、更低的溶解度以及强烈的聚集倾向。总体而言，这些发现突出了酵母衍生蛋白质作为生物表面活性剂的潜力，并表明pH控制沉淀可以在食品配方中调整其功能。
