Characterization of Citrus Peel Maturation to Reduce Postharvest Storage Problems in Florida

Abstract

This is a study to create an index to measure the rate of peel matura­tion in citrus as it relates to postharvest handling and keeping quality. Currently, citrus is harvested based on internal quality. Peel changes have not been related to best harvest time. Several physical and chemical parameters were measured for harvest dates to determine if peel maturation and senescence can be moni­tored by some combination of measures in order to minimize fruit disorders during storage resulting from immature or senescent peel or unusual stress that the peel may have been subjected to. Water stress and growth regulators were used to induce differences in biochemical changes and change the rate of peel maturation. Changes in levels of sugars, glycosidases, abscisic acid, and volatile components during maturation coincided with changes in peel color, percent fruit drop, and with fruit characteristics during storage (weight loss, decay, and chilling injury) may be useful for establishing harvest date guidelines, so that less postharvest injuries occur while the fruit still has acceptable internal qual­ity. Days from bloom date, detachment force, and peel reducing sugars were the best indicators for a peel senescence index. It was not clear whether peel and pulp maturity changes occur simultaneously or differentially during the season; however, changes in TSS: acid ratio were sometimes significantly related to changes in weight loss, decay, and chilling injury of the peel, which may give in­dication about the coincidence of pulp and peel maturity.