Changes in the pectic fraction of bush butter (<i>Dacryodes edulis</i> (G Don) HJ Lam) fruit pulp during ripening

Abstract

Abstract CDTA‐soluble polysaccharides were extracted from cell wall material (prepared as alcohol‐insoluble solids) of bush butter fruit endocarp tissue at three stages of ripeness. The amount of soluble pectins remained constant but they underwent a gradual depolymerisation during ripening. The CDTA extracts were fractionated by anion exchange and the subfractions were analysed for their sugar composition and molecular weight distribution. For all degrees of ripeness the extracts were composed of three minor peaks and two major peaks. The minor peaks appeared to be composed of xyloglucan and mannan‐type polymers for the first peak and arabinogalactan‐type polymers for the other two peaks. The two main peaks were retained on the column. The first was exclusively composed of homogalacturonan polymers and the second contained principally highly branched rhamnogalacturonan polymers. During ripening, both homogalacturonan and rhamnogalacturonan populations were modified. Modifications in the rhamnogalacturonan fraction were principally marked by the accumulation of low‐molecular‐weight rhamnoglacturonan polymers in the course of ripening. © 2001 Society of Chemical Industry