Romo María, Castellari Massimo, Bou Ricard, Gou Pere, Felipe Xavier
Food Processing and Engineering Programme, Institute for Food and Agricultural Research and Technology (IRTA), Granja Camps i Armet s/n, Monells, 17121 Girona, Spain.
Food Safety and Functionality Programme, Institute for Food and Agricultural Research and Technology (IRTA), Granja Camps i Armet s/n, Monells, 17121 Girona, Spain.
Foods. 2023 Jul 12;12(14):2688. doi: 10.3390/foods12142688.
Whey from goat and sheep have been gaining attention in the last few years for their nutritional properties. Unfortunately, β-Lg, not found in human milk, may trigger infant allergies if used in infant food formulations, so there is a growing interest in developing ingredients derived from whey with higher α-La/β-Lg ratios. The objective of this work was to study the effect of high-pressure processing (HPP) on caprine and ovine native whey concentrates (NWC) in order to obtain α-Lactalbumin (α-La)-enriched fractions. NWCs were treated at 600 MPa (23 °C) for 2, 4, and 15 min and two pH conditions were studied (physiological pH and pH 4.60). The concentration of β-Lg in supernatant fraction after HPP significantly decreased after 2 min of treatment, while the concentration of α-La was unchanged in both goat and sheep samples. Longer HPP processing times (up to 15 min) progressively increased α-La purification degree but also decreased the α-La yield. Caprine and ovine NWCs treated at physiological pH provided better α-La yield, α-La purification degree, and higher β-Lg precipitation degrees than the corresponding acidified samples, while the corresponding NWC supernatant (NWC) showed lower values for both surface hydrophobicity and total free thiol indices, suggesting a higher extent of protein aggregation. Effects of sample acidification and the HPP treatment were opposite to those previously reported on bovine NWC, so further characterization of caprine and ovine β-Lg should be carried out to understand their different behavior.
在过去几年中，山羊和绵羊乳清因其营养特性而备受关注。不幸的是，人乳中不存在的β-乳球蛋白（β-Lg）如果用于婴儿食品配方中可能会引发婴儿过敏，因此人们对开发α-乳白蛋白（α-La）/β-Lg比例更高的乳清衍生成分的兴趣与日俱增。这项工作的目的是研究高压处理（HPP）对山羊和绵羊天然乳清浓缩物（NWC）的影响，以获得富含α-乳白蛋白（α-La）的组分。NWC在600 MPa（23°C）下处理2、4和15分钟，并研究了两种pH条件（生理pH和pH 4.60）。HPP处理后2分钟，上清液组分中β-Lg的浓度显著降低，而山羊和绵羊样品中α-La的浓度均未改变。更长的HPP处理时间（长达15分钟）逐渐提高了α-La的纯化程度，但也降低了α-La的产量。在生理pH下处理的山羊和绵羊NWC比相应的酸化样品提供了更好的α-La产量、α-La纯化程度和更高的β-Lg沉淀程度，而相应的NWC上清液（NWC）在表面疏水性和总游离巯基指数方面均显示出较低的值，表明蛋白质聚集程度更高。样品酸化和HPP处理的效果与先前报道的牛NWC的效果相反，因此应进一步表征山羊和绵羊β-Lg，以了解它们的不同行为。
