Changes in starch during malting of finger millet (Ragi, <Emphasis Type="Italic">Eleusine coracana</Emphasis>, Indaf-15) and its in vitro digestibility studies using purified ragi amylases

Malting of finger millet resulted in a decrease in its starch content and an apparent increase in its amylose value. Scanning electron microscopy studies of ungerminated and germinated starches showed a pattern of granular hydrolysis, which was dependent on the size and shape; big granules appeared to be more susceptible than small granules. Malting did not affect the relative viscosity of starches isolated from ragi malts. Purified !-1 amylase was found to hydrolyze germinated ragi starches (24, 48, 72 and 96 h) to an extent of 50-60%, whereas for !-2 and !-3 amylases it was in the range of 50-55% and 60-70% respectively. Amylose contents of starches did not have any visible effect on the extent of hydrolysis. Maltotetraose was the major oligosaccharide produced by these enzymes from all the germinated starches after 15 min of hydrolysis. Higher oligosaccharides (degrees of polymerization of 8 and above) underwent further degradation after 120 min hydrolysis.