Protein and Amino Acid Profiles of Different Whey Protein Supplements

ABSTRACT

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.

KEYWORDS. :

• amino acids
• dietary supplement
• α-lactalbumin
• β-lactoglobulin

ACKNOWLEDGMENTS

The authors would thank Ricky Toledano for preparing the English version of the manuscript and The Research Foundation of the State of Rio de Janeiro—FAPERJ and National Council of Technological and Scientific Development (CNPq) by provided financial support for the study (process no. E-26/103.003/2012 and 311361/2013-7, respectively). Cristine C. Almeida and Marion P. Costa were supported by scholarship from CNPq.

Declaration of interest: The authors have no conflicts of interest that are directly relevant to the content of this manuscript. The authors alone are responsible for the content and writing of the article.