The metabolism of nitrogen and the digestibility coefficient and biological value of the proteins and net protein utilization in poor rice diet supplemented with methionine-fortified soya flour or skim milk powder
Panemangalore, M.; Parthasarathy, H.N.; Joseph, K.; Sankaran, A.N.; Rao, M.N.rayana; Swaminathan, M.
Canadian Journal of Biochemistry 42(5): 641-650
The effect of supple-menting a poor rice diet commonly used in India with methionine-fortified soya flour or skim milk powder was studied in seven girls aged 8-9 years, using as criteria: the retention of nitrogen, digestibility coefficient, biological value, and net protein utilization of the proteins. The retention of nitrogen on the rice diet was very low (20.3 mg/kg day). Supplementation of the rice diet with soya flour, methionine-foritfied soya flour or skim milk powder, so as to provide about 1 g/kg extra protein, made up the protein deficiency in the rice diet and resulted in a significant increase in nitrogen retention (95.6, 112.1, and 113.6 mg/kg day). The retention of nitrogen on the rice diet supplemented with methionine-fortified soya flour (112.1 mg/kg day) or skim milk powder (113.6 mg/kg day) was nearly the same and significantly higher than that (95.6 mg/kg day) observed with a diet supplemented with soya flour. The biological value and net protein utilization of the mixed proteins of rice-skim milk powder diet and rice-methionine-fortified soya flour diet (62.4 and 62.2 and 53.3 and 54.0 respectively) were nearly the same and significantly higher than those (58.3 and 49.9) of rice-soya flour diet. The results show that methionine-fortified soya flour is almost as good as skim milk powder and significantly superior to soya flour as a protein supplement to rice diet.