Nutritive value of globin-amino acid and complementary globin-cereal mixtures
Landmann, W.A.; Dill, C.W.; Young, C.R.
Journal of Nutrition 110(11): 2254-2262
1980
ISSN/ISBN: 0022-3166 PMID: 7431125 Document Number: 166322
Protein efficiency ratios (PER) were estimated using male weanling rats given diets with bovine globin alone or with wheat and maize gluten. Simultaneous equations and graphical methods were devised for selecting combinations of globin and cereal proteins to provide optimum and suboptimum profiles of limiting amino acids. Supplementation of the globin with amino acids established isoleucine and methionine as limiting amino acids. Addition of globin, the amino acid pattern of which is complementary to that of the cereal proteins, markedly improved PER. Growth rates of rats given different combinations of proteins were not identical, even though PER values differed only slightly. The PER of combined proteins were not predictable from amino acid composition or from correlations between PER and chemical score based on National Research Council requirements for essential amino acids. The inability of the optimum mixtures to meet expected nutritional performance clearly indicated that other factors affecting availability of amino acids are implicated. Nevertheless, mutual improvement of two incomplete proteins such as globin and wheat or maize gluten was demonstrated. Addition of globin to widely used diets consisting mainly of maize or wheat can be nutritionally beneficial.