Mutagenesis Induced Variations in Trypsin Inhibitor Levels and their Impact on Enhancing the Nutritive Value of Moth Bean (Vigna aconitifolia (Jacq.) Marechal)

Abstract

Mutagenesis-induced variation in trypsin inhibitor levels has been demonstrated as a critical mechanism for enhancing the nutritive value of moth bean (Vigna aconitifolia (Jacq.) Marechal). Induced mutation techniques, primarily using agents like EMS (ethyl methane sulphonate) and SA (sodium azide), have resulted in considerable variability in trypsin inhibitor profiles among both viable mutants and micromutants of moth bean. Trypsin inhibitors are antinutritional factors commonly present in legume seeds, which can limit protein digestibility and overall nutritional quality. Treated seeds, especially with optimal concentrations of EMS and SA, show significant changes in both seedling vigor and protein-related traits. Trypsin inhibitor assays were carried out to find out the trypsin inhibitor activity among seven viable mutants and 78 micromutants of moth bean which were developed by induced mutation breeding. Present study has shown that mutagenesis can induce a reduction in trypsin inhibitor content by approximately 25% to 45% in certain lines. The pertinent studies of seven viable mutants and 78 micromutants of moth bean have indicated considerable variation regarding TI level. The lowest TI (180.00 TIU/min/gm meal) could be recorded in 6/IV-mutant, while the 7/IV-mutant revealed the highest TI content (326.16 TIU/min/gm meal). The electrophoretic profiles of trypsin inhibitors on X-rays film revealed 3 to 7 isoinhibitors in different viable mutants and micromutants of moth bean. The mutants showing reduced trypsin inhibitor bands were quantitatively estimated. The lowest TI activity (187.98 TIU) was observed in B6 mutant, which was evolved by the 0.15% EMS treatment. To nullify trypsin inhibitor activity in moth bean seeds, so as to use it in diet, the heat treatment and germination studies have been tried in some of its mutant lines. The processing method involving heat treatment almost eliminated trypsin inhibitor activity while soaking and germination partly removed the activity. Lowered trypsin inhibitor levels lead to enhanced protein digestibility and improved nutritional value of the bean, making it more suitable for direct human consumption and as animal feed.