ENZYMATIC STARCH HYDROLYSIS OF EXTRUDED POTATO PEELS

Potato peels discarded by potato processors are a potential source of dietary fiber and starch. This starch may be hydrolyzed for fermentation to value-added products. Dried steam peels were extruded at 135 degrees C and 22% feed moisture and digested with alpha-amylase and/or amyloglucosidase. Two barrel temperatures and feed moistures were also studied. Glucose was measured colorimetrically at 0,1,2,4,8 and 24h of incubation. All peels treated with either no enzymes or alpha-amylase alone produced minimal glucose. Nonextruded peels digested with both enzymes produced more glucose than did those treated with amyloglucosidase alone. Complete digestion of starch occurred in extruded peels digested with amyloglucosidase, but not when alpha-amylase was used.