POTATO PEEL DIETARY FIBER COMPOSITION - EFFECTS OF PEELING AND EXTRUSION-COOKING PROCESSES

Potato peels are a potential source of dietary fiber. The abrasion pee ling method used by chip manufacturers results in more starch and less dietary fiber than the steam peeling procedure used for production of dehydrated potatoes. The objective of this study was to identify diff erences in dietary fiber composition between these types of peels and the effects of extrusion on fiber. Peels were extruded in a twin screw extruder at barrel temperatures of 110 or 150 degrees C and feed mois tures of 30% or 35%. Extrusion cooking reduced starch content and incr eased total dietary fiber in steam peels. Total dietary fiber in abras ion peels was not affected by extrusion. Extrusion increased soluble n onstarch polysaccharides in both types of peels. More glucose was reco vered from insoluble fiber of extruded steam peels than from abrasion peels, suggesting that resistant starch may have been formed. Lignin i ncreased in extruded steam peels but decreased in extruded abrasion pe els.