Cell wall-degrading enzymes and changes in cell wall polysaccharides during ripening and storage of bush butter (Dacryodes edulis (G. Don) H.J. Lam) fruit

摘要

Activities of cell wall-degrading enzymes and amounts of pectins and hemicelluloses were measured in bush butter fruits at seven stages of ripeness, from unripe to soft fruits. Enzyme assays showed that only polygalacturonase (PG) and pectinmethylesterase (PME) were present in high amounts. The PME activity remained almost constant throughout ripening while that of PG drastically increased. The other enzymes assayed, including cellulases and hemicellulases, appeared to be absent or present only in very low quantities. Chelator-soluble pectin was the only class of polysaccharides that underwent degradation during ripening. The apparent molecular weight of chelator-soluble pectin decreased during ripening while those of alkali-soluble hemicelluloses remained unchanged.