THE MODE OF ACTION ON GRANULAR WHEAT-STARCH BY BACTERIAL ALPHA-AMYLASE

Large (A) and small (B) granules from wheat starch were subjected to a lpha-amylolysis. The B granules were solubilised faster than the A gra nules. The solubilised dextrins we separated from the enzyme before a secondary hydrolysis of the products occurred and then characterized. The size-distribution of the hydrolysis products ranged between a degr ee of polymerization of 2-500. The dextrins solubilised from the B gra nules contained somewhat more linear fragments and had smaller average chain length than the corresponding dextrins from the A granules. The composition of the residues of the A granules remained practically un changed, whereas the B granules contained somewhat less amylose. Both granule types possessed extensive fragmentation of some granules, wher eas other granules were virtually untouched by the enzyme.