SOME PROPERTIES AND DEGRADABILITY OF ISOLATED STARCH GRANULES

Starch granules of 11 starchy feedstuffs were isolated. An isolation procedure is presented. The procedure did not damage the starch granules, as could be proven by scanning electron microscopy. The starch granules were nearly completely defatted by the procedure and only about 0.5% of the original protein remained in the starch, except for rice starch. The content of apparent and real amylose was measured in the isolated starch granules. Degradability of raw materials and isolated starch granules was determined with α‐amylase and rumen fluid. Starch of tapioca and rice was relatively easy to degrade by α‐amylase and rumen fluid, while potato starch was relatively difficult to degrade by α‐amylase. Starches containing a low amount of amylose were found to degrade faster than starches containing a high amount of amylose. Copyright © 1990 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim