Department of Food Science, The University of Tennessee, Knoxville 37996, USA.
Department of Food Science, The University of Tennessee, Knoxville 37996, USA.
Food Chem. 2021 May 15;344:128639. doi: 10.1016/j.foodchem.2020.128639. Epub 2020 Nov 16.
Clear acidic protein beverages have a niche market. Acidification of skim milk powder (SMP) dispersions to pH 3.0 using citric acid (CA) lowers turbidity but the dispersion remains translucent. The present study aimed at comparing physicochemical properties of 5% w/v SMP dispersions acidified to pH 3.0 using chelating gluconic acid (GA) and CA and non-chelating hydrochloric acid. GA was the most effective in reducing the dispersion turbidity to 394 NTU at pH 3.0, which was further reduced to 248 NTU after heating at 90 °C for 2 min resulting in transparent dispersions. The better chelating ability of GA than CA was supported by the higher extent of dissolved CCP in serum phase. The aggregation of dissociated caseins was not observed for the GA treatment based on transmission electron microscopy. The findings from this study may be used to produce clear casein-based protein beverages.
澄清酸性蛋白饮料有一定的市场。使用柠檬酸（CA）将脱脂奶粉（SMP）分散体酸化至 pH 3.0 会降低浊度，但分散体仍保持半透明。本研究旨在比较使用螯合葡萄糖酸（GA）和 CA 以及非螯合盐酸将 5%w/v SMP 分散体酸化至 pH 3.0 时的物理化学性质。在 pH 3.0 时，GA 最有效地将分散体浊度降低至 394 NTU，在 90°C 加热 2 分钟后进一步降低至 248 NTU，从而得到透明的分散体。GA 比 CA 具有更高的血清相中溶解 CCP 的程度，这支持了 GA 的更好的螯合能力。基于透射电子显微镜，未观察到 GA 处理下分离的酪蛋白的聚集。本研究的结果可用于生产澄清的基于酪蛋白的蛋白饮料。
