EFFECT OF STORAGE OF APPLE ON THE ENZYMATIC-HYDROLYSIS OF CELL-WALL POLYSACCHARIDES

Cell wall materials in the form of water-insoluble solids (WIS) and wa ter-soluble fractions (WSF) were prepared from apples stored at 4 degr ees C for 30 weeks. During storage, the WIS content decreased whereas the WSF content remained unchanged. The total amount of polysaccharide s decreased, in particular the pectic polymers which decreased by 10%. In contrast, the soluble pectic fraction increased by 40% whilst its degree of methoxylation remained constant. The arabinose and galactose content progressively declined. The enzymatic treatment of the apple tissues was more effective the longer the storage; yields correlated w ell with the enzyme hydrolysis of WIS. The accessibility of pectin to polygalacturonases in apple tissues is discussed since it was higher a t the end of storage, whereas the solubilisation of pectins from WIS b y polygalacturonases remained constant. On the other hand, with liquef ying enzymes, the yield of pectin solubilisation from apple tissues or WIS were well correlated and increased with storage time. Copyright ( C) 1996 Elsevier Science Ltd