OBJECTIVE:The objective was the chemical and nutritional study of a bovine whey protein isolate, a bovine collagen hydrolysate and mixtures of the two products aiming at high nutritional and functional value. METHODS: Centesimal composition and amino acid analyses were performed on both proteinaceous materials for the calculation of an adequate amino acid profile based on the Food and Agriculture Organization/World Health Organization recommendation. The nutritive value indexes for the whey protein isolate, the collagen hydrolysate and mixtures of both proteins were determined in rats through growth assay and nitrogen balance. The experimental parameters from nutritional assays were submitted to analysis of variance and the Tukey test applied for differences among means (p<0.05). RESULTS: The whey protein isolate met all the requirements of the Food and Agriculture Organization/World Health Organization reference for essential amino acids while the collagen hydrolysate showed deficiency in all essential amino acids and complete absence of tryptophan. The casein showed higher efficiency than the whey isolate and mixtures of both proteins in promoting growth in the rat. There was no statistical difference in growth between the whey protein isolate and the mixture of 60% whey protein isolate and 40% collagen hydrolysate. In all other indexes of protein nutritive value the mixture 60% whey protein isolate and 40% collagen hydrolysate revealed itself equal or superior to casein and the 100% whey isolate. CONCLUSION: The protein mixture 60% whey protein isolate and 40% collagen hydrolysate showed high nutritive value and water solubility indexes, considered favorable properties as an ingredient for the formulation of dietetic products for elderly people.
Collagen; Milk proteins; Whey protein isolate
