Pectolytic Enzyme Studies for Peeling of Grapefruit Segment Membrane

Abstract

ABSTRACT In vitro studies of commercial pectolytic enzymes with grapefruit membranes and citrus pectin were conducted to determine optimum conditions for peeling membranes from grapefruit segments. Alcohol‐insoluble solids residue (AIS) extracted from washed membrane consisted of ca. 46% pectic substances and 25% neutral sugars. The main neutral sugar of AIS was glucose, followed by arabinose and xylose. Optimum conditions for degradation of segment membranes by pectinase “C‐80” were: pH between 4.0 and 5.0 at 55°C. Optimum temperature for degradation of commercial pectin was 50°C; this indicates that optimum conditions for enzymatic activation depend also on the substrate degraded. The enzyme was fully inactivated after 1 min at 80°C. This study provides additional basic information for industrial application of enzymatic peeling of citrus segments.