[Effect of germination on protein quality of wheat and mung beans--studies of nitrogen balance in growing rats].

The bioavailability of limiting amino acids (lysine, cystine and methionine), which are formed during the germination of wheat and mung beans, was assessed in nitrogen balance trials on growing rats. In addition, the influence of heat treatment on the protein nutritional value of wheat and mung beans was determined. Compared to ungerminated wheat, net protein utilization (NPU) and biological value (BV) increased from 30% and 36% to 41% and 52%, respectively. Apparent protein digestibility (PD) decreased from 82% to 79% during 4 day germination. Heat treatment improved PD from 82% to 85% in ungerminated wheat, but not during germination. NPU and BV were not changed by heat treatment. Feeding germinated mung beans caused a markedly reduced feed intake by the animals, which made it impossible to evaluate changes in protein nutritional value during germination. Heat treatment of ungerminated mung beans improved PD, NPU and BV from 77%, 38% and 49% to 81%, 48% and 60%, respectively. The results indicate that the amino acids, in particular lysine, which are formed in germinating wheat, are available to the rat. Heat treatment will improve considerably the protein nutritional value of ungerminated mung beans.