Protein and amino acid analyses of some protein/amino acid preparations sold in Canada
1992
Sarwar, G. | Ujiie, M. | Botting, H.G.
Eight protein/amino acid products sold as food supplements in Canada were analysed for protein and amino acids. Six products were based on protein (casein, egg albumin and/or lactalbumin) hydrolysates plus crystalline amino acids, while two were based on mixtures of crystalline amino acids. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) of the products based on protein hydrolysates revealed the presence of a number of high molecular weight (up to > 100 kD) protein fragments in some products, suggesting incomplete hydrolysis in these products. However, SDS-PAGE did not provide quantitative information on the percent of total hydrolysis of proteins. Free amino acids in products based on protein hydrolysates were present at < 1 to 9% of total amino acids, suggesting a very small degree of complete hydrolysis in these products. Individual essential and total amino acids in products based on protein hydrolysates were present at 15-97% of the amounts claimed on the label. Contrary to the label claim of the presence of 22 amino acids in two products, based on a mixture of crystalline amino acids, only lysine was found. Two products based on protein hydrolysates contained abnormally high levels of hydroxyproline and glycine, suggesting the presence of a protein high in these amino acids such as gelatin.
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