Food Science Department, University of Guelph, Guelph, Canada.
Instituto de Laticínios Cândido Tostes - Epamig, Juiz de Fora, Brazil.
J Dairy Res. 2019 Aug;86(3):347-353. doi: 10.1017/S0022029919000426. Epub 2019 Jul 12.
The objective of this work was to evaluate the impact of changes during membrane filtration on the heat stability of milk protein concentrates. Dairy protein concentrates have been widely employed in high protein drinks formulations and their stability to heat treatment is critical to ensure quality of the final product. Pasteurized milk was concentrated three-fold by membrane filtration, and the ionic composition was modified by addition of water or permeate from filtration (diafiltration). Diafiltration with water did not affect the apparent diameter of the casein micelles, but had a positive effect on heat coagulation time (HCT), which was significantly longer (50 min), compared to the non diafiltered concentrates (about 30 min). UHT treatments increased the particle size of the casein micelles, as well as the turbidity of retentates. Differences between samples with and without diafiltration were confirmed throughout further analysis of the protein composition of the unsedimentable fraction, highlighting the importance of soluble protein composition on the processing functionality of milk concentrates.
本工作旨在评估膜过滤过程中变化对乳蛋白浓缩物热稳定性的影响。乳蛋白浓缩物已广泛应用于高蛋白饮料配方中，其对热处理的稳定性对于确保最终产品的质量至关重要。巴氏杀菌奶通过膜过滤浓缩三倍，并通过添加水或过滤渗透物（渗滤）来改变离子组成。水渗滤不会影响酪蛋白胶束的表观直径，但对热凝固时间（HCT）有积极影响，与未经渗滤的浓缩物相比（约 30 分钟），HCT 显著延长（50 分钟）。UHT 处理增加了酪蛋白胶束的粒径以及保留物的浊度。通过进一步分析不可沉淀部分的蛋白质组成，证实了有无渗滤样品之间的差异，突出了可溶性蛋白质组成对乳浓缩物加工功能的重要性。
