Research Program in Biological Sciences, Institute of Exact and Biological Sciences, Federal University of Ouro Preto, Ouro Preto, Minas Gerais, Brazil.
J Med Food. 2010 Dec;13(6):1505-9. doi: 10.1089/jmf.2009.0222. Epub 2010 Sep 27.
Nutritional and biochemical properties of noncommercial whey protein have been described since 1950. However, comparisons between commercial whey protein for human consumption and casein are rarely found. The aim of this study was to compare biological quality of a commercial whey protein with casein and its effect on biochemical parameters of rats. Thirty-two weanling Fisher rats were divided into three groups and given the following diets: casein group, standard diet (AOAC); whey protein group, modified AOAC diet with whey protein instead of casein; and casein:whey group, modified AOAC diet with 70%:30% casein:whey. A protein-free group was used for determination of endogenous nitrogen losses. Net protein ratio, protein efficiency ratio, and true digestibility were determined, and blood was collected for biochemical analysis. When compared with casein, whey protein showed significant differences for all biological parameters evaluated, as well as for albumin, total protein, total cholesterol, and glucose concentrations. Replacing 30% of casein with whey protein did not affect these parameters. A positive relation among whey protein, high-density lipoprotein-cholesterol, and paraoxonase activity was found. Hepatic or renal dysfunctions were not observed. In conclusion, in comparison with casein, commercial whey protein had higher values of biological parameters, and biochemical evaluation revealed it improved glycemic homeostasis, lipid status, and paraoxonase activity in rats.
自 1950 年以来，人们就已经描述了非商业乳清蛋白的营养和生化特性。然而，人们很少将用于人类消费的商业乳清蛋白与酪蛋白进行比较。本研究旨在比较商业乳清蛋白与酪蛋白的生物学质量及其对大鼠生化参数的影响。将 32 只断奶 Fisher 大鼠分为三组，分别给予以下饮食：酪蛋白组，标准饮食（AOAC）；乳清蛋白组，用乳清蛋白代替酪蛋白的改良 AOAC 饮食；酪蛋白：乳清蛋白组，用 70%：30%的酪蛋白：乳清蛋白代替酪蛋白的改良 AOAC 饮食。还设立了一个无蛋白组，用于测定内源性氮损失。测定了净蛋白比、蛋白效率比和真消化率，并采集血液进行生化分析。与酪蛋白相比，乳清蛋白在所有评估的生物学参数以及白蛋白、总蛋白、总胆固醇和葡萄糖浓度方面均显示出显著差异。用乳清蛋白替代 30%的酪蛋白不会影响这些参数。还发现乳清蛋白与高密度脂蛋白胆固醇和对氧磷酶活性之间存在正相关关系。未观察到肝或肾功能异常。总之，与酪蛋白相比，商业乳清蛋白具有更高的生物学参数值，生化评估显示它改善了大鼠的血糖稳态、脂质状况和对氧磷酶活性。
