Characterization of strawberry pectin extracted by chemical means

Abstract

Alcohol Insoluble Residue was obtained from fresh strawberry fruit (37 g/kg). Pectic material was successively extracted from the residue by trans 1,2- Diamino Cyclohexane - N,N,N′,N′- Tetra Acetic acid (CDTA), hot succinic acid in succinate buffer, hot dilute HCl and cold dilute NaOH. The extracts were analysed for uronic acids, neutral sugars and proteins contents using colorimetric and GC methods and were subjected to ion exchange chromatography. A large portion of the strawberry pectin (474 g/kg) was extracted by a calcium sequestrant (CDTA). The proportion of arabinogalactans present as side-chains of the rhamnogalacturonan increased with the progress of the extractions. Ion exchange of chromatography revealed that soluble pectin (calcium-linked) and protopectin (cell wall-linked) were accompanied by proteins and other neutral sugars such as xylose and glucose. However, the presence of xyloglucans was suspected because of the high proportions of glucose and xylose in the CDTA fractions purified by ion exchange chromatography.