Department of Food Science, University of Guelph, Guelph, ON, N1G2W1, Canada.
Department of Food Science, University of Guelph, Guelph, ON, N1G2W1, Canada; iFood Center, Department of Food Science, Aarhus University, Blichers Alle, Foulum, Denmark 8830.
J Dairy Sci. 2019 Sep;102(9):7760-7764. doi: 10.3168/jds.2019-16547. Epub 2019 Jul 10.
Milk protein concentrates are common ingredients in the dairy industry, with varying processing histories and composition. The objective of this research was to determine the feasibility of using the whey protein nitrogen (WPN) index, a well-established index for skim milk powder and nonfat dry milk, as a quality parameter for milk protein concentrates. The WPN index is a value based on the moisture-adjusted weight of skim milk powder. We hypothesized that WPN, even when standardized based on protein, may change depending on solubilization conditions of milk protein concentrates because of differences in solubilization conditions or processing history. The WPN was measured for model concentrates with different thermal history or reconstitution conditions. The WPN was not affected by an increased concentration of soluble casein in the dispersions nor after solubilization of the powder at 22 or 60°C. All reconstituted samples were standardized for protein. The WPN was also in full accordance with residual native protein measured by chromatography.
乳蛋白浓缩物是乳制品行业常见的成分，具有不同的加工历史和组成。本研究的目的是确定乳清蛋白氮（WPN）指数作为乳蛋白浓缩物质量参数的可行性，WPN 指数是基于脱脂奶粉的水分调整重量的一个值。我们假设，即使基于蛋白质进行标准化，WPN 也可能因乳蛋白浓缩物的溶解条件或加工历史的不同而发生变化。我们测量了具有不同热历史或再溶解条件的模型浓缩物的 WPN。分散液中可溶性酪蛋白浓度的增加或在 22 或 60°C 下溶解粉末后，WPN 均不受影响。所有再溶解的样品均按蛋白质标准化。WPN 也与色谱法测量的残留天然蛋白质完全一致。
