Pectin Changes in Ripening Cherry Fruit

Pectin solubilization was studied during ripening of cherry fruit. Pectic materials were isolated at specific stages during development. The proportion of alcohol-insoluble-material decreased on a fresh weight basis with ripeness, but increased per fruit. Pectic substances were divided into water-, oxalate- and acid-soluble fractions. The oxalate-and water-soluble part increased as acid-soluble components decreased. Water- and acid-soluble fractions contained many more neutral sugar residues than the oxalate-soluble fraction. Changes in individual sugars indicated the major alterations were the degradation of galactan and the absence of arabinan solubilization in acid-soluble pectic substance. Size exclusion chromatography showed absence of pectin depolymerization during ripening, indicating that fruit softening does not depend on pectin depolymerization.