ABSTRACT
Amylolytic enzymes represent a group of starch hydrolases and related enzymes that are active towards the α-glycosidic bonds in starch and related poly and oligosaccharides.
This study investigated the most appropriate condition(s) for the induction of amylolytic enzymes (α & β-amylases) in acha (Digitaria exilis) and iburu (Digitaria iburua) malts. Acha and iburu grains were steeped in water for 24h, at room temperature and germinated for 1–12 days to obtain green malt. Amylolytic activities were determined in the green malt every 24 h, in order to determine the optimum day for malt development which was taken to be the malt containing the highest amount of amylolytic activity. The optimum day of malt development was chosen and served as the template for further steeping experiments conducted in water containing phosphate salt at pH4.0–8.0 and at different temperatures (0, 20, 30, 40, 50, & 60°C). The amylolytic activity present in the extract was determined in order to obtain the optimum pH and temperature for α & β-amylases induction. Sixth day of germination produced highest amylolytic activity for both grains when steeped in water and fivefold higher activity was induced at pH 6.5 compared to water at 30°C which is a traditional steeping medium. This study concluded that amylolytic enzymes (α & β-amylases) produced by this grains under this optimized condition are more abundant than amylases produced by the same grains using the traditional method.
Keywords: Amylolytic activity, α-amylase, β-amylase, Optimum condition, pH, Acha (Digitaria exilis), Iburu (Digitaria iburua).