Abstract
The effect of fortification of a meatless meat, a textured soy protein, with methionine and lysine was examined with growing male rats. The growth of rats fed 8% protein meatless meat diet was improved by supplementing 0.142% methionine, the first limiting amino acid, whereas the fortification of 0.192% and 0.288% lysine, the second limiting factor, caused the depression of growth rate. The depression of food intake occured on the first day of feeding with the lysine fortified diet, while the fortification of methionine stimulated food intake. When normal young rats were offered three kinds of meatless meat diets, non-fortified, fortified with 0.192% lysine, and with 0.192% lysine and 0.164% methionine, they ate the methionine fortified diet in preference, while protein depleted rats did not. Elevated concentration of free lysine and depressed concentration of free methionine in blood plasma were observed in rats fed the meatless meat diet fortified with 0.192% lysine, and most of liver of rats with more than 0.096 lysine fortified diets was observed to be fatty. It was suggested, from these results, that amino acid imbalance may occur when the meatless meat is fortified with more than 0.1% lysine.
