Blood amino acid studies in the weanling rat on diets containing raw and cooked black gram (Phaseolus mungo).

Weanling male rats were fed diets containing 10% protein from
raw or cooked black 9tam for one week. Free lysine, methionine, threonine
and tryptophan were determined in the blood obtained fl;.om the animals.
Plasma amino acid (PM) scores indicated that methionine is limiting in
black gram proteins. Plasma levels of lysine, methionine, threonine and
tryptophan were similar in rats fed raw or cooked black gram. In vitro
enzymatic hydrolysis with pepsin followed by pancreatin also showed that
the four amino acids are released to the same extent from the raw 0.. cooked
material. These results indicate that the trypsin inhibitor of black gram,
at the level present may not affect the liberation of amino acids during
·digestion of the proteins.
Although the growth rates of rats fed cooked black gram were much
higher than those fed the raw gram. the protein efficiency ratio (PER) was
not affected as a result of cooking the legume. Supplementation of cooked
black gram With methionine resulted in marked increases in the growth rate
of rats and PER indicating that methionine is a first limiting amino acid in
the proteins of black gram. Addition of threonine along With methionine
brought about further improvements in the growth rate of rats fed methionine supplemented
black gram diet indicating that threonine Is a second limiting
amino acid in black gram proteins. Further, the presence of law amounts of
cystine In black gram indicates that methionine and cystine are the first
limiting amino acids in this legume.