Almeida Cristine C, Alvares Thiago S, Costa Marion P, Conte-Junior Carlos A
a Department of Food Technology , Fluminense Federal University , Rio de Janeiro, Rio de Janeiro, Brazil.
b Nutrition Institute , Federal University of Rio de Janeiro , Rio de Janeiro, Brazil.
J Diet Suppl. 2016;13(3):313-23. doi: 10.3109/19390211.2015.1036187. Epub 2015 Aug 28.
Whey protein (WP) supplements have received increasing attention by consumers due to the high nutritional value of the proteins and amino acids they provide. However, some WP supplements may not contain the disclosed amounts of the ingredients listed on the label, compromising the nutritional quality and the effectiveness of these supplements. The aim of this study was to evaluate and compare the contents of total protein (TP), α-lactalbumin (α-LA), β-lactoglobulin (β-LG), free essential amino acids (free EAA), and free branched-chain amino acids (free BCAA), amongst different WP supplements produced by U.S. and Brazilian companies. Twenty commercial brands of WP supplements were selected, ten manufactured in U.S. (WP-USA) and ten in Brazil (WP-BRA). The TP was analyzed using the Kjeldahl method, while α-LA, β-LG, free EAA, and free BCAA were analyzed using HPLC system. There were higher (p < 0.05) concentrations of TP, α-LA, β-LG, and free BCAA in WP-USA supplements, as compared to the WP-BRA supplements; however, there was no difference (p > 0.05) in the content of free EAA between WP-USA and WP-BRA. Amongst the 20 brands evaluated, four WP-USA and seven WP-BRA had lower (p < 0.05) values of TP than those specified on the label. In conclusion, the WP-USA supplements exhibited better nutritional quality, evaluated by TP, α-LA, β-LG, and free BCAA when compared to WP-BRA.
乳清蛋白（WP）补充剂因其提供的蛋白质和氨基酸具有高营养价值而受到消费者越来越多的关注。然而，一些WP补充剂可能未含有标签上所披露的成分含量，从而损害了这些补充剂的营养质量和功效。本研究的目的是评估和比较美国和巴西公司生产的不同WP补充剂中总蛋白（TP）、α-乳白蛋白（α-LA）、β-乳球蛋白（β-LG）、游离必需氨基酸（游离EAA）和游离支链氨基酸（游离BCAA）的含量。选择了20个WP补充剂商业品牌，其中10个在美国生产（WP-USA），10个在巴西生产（WP-BRA）。TP采用凯氏定氮法分析，而α-LA, β-LG, 游离EAA和游离BCAA采用高效液相色谱系统分析。与WP-BRA补充剂相比，WP-USA补充剂中TP、α-LA、β-LG和游离BCAA的浓度更高（p < 0.05）；然而, WP-USA和WP-BRA之间游离EAA的含量没有差异（p > 0.05）。在评估的20个品牌中，4个WP-USA和7个WP-BRA的TP值低于标签上规定的值（p < 0.05）。总之，与WP-BRA相比，通过TP、α-LA、β-LG和游离BCAA评估，WP-USA补充剂表现出更好的营养质量。
