ACCUMULATION OF ANTIOXIDANTS IN APPLE PEEL AS RELATED TO PREHARVEST FACTORS AND SUPERFICIAL SCALD SUSCEPTIBILITY OF THE FRUIT

Antioxidants are believed to protect against the oxidation of alpha-fa rnesene to conjugated trienes in apple (Malus domestica, Borkh.) peel, thus providing resistance against superficial scald development. We c onducted three experiments in which apples were a) harvested meekly, d uring which they were exposed to increasing hours at <10C during ripen ing; b) induced to ripen with no hours at <10C by applying ethephon; a nd c) enclosed in paper bags as they ripened. Inducing ripening with e thephon increased total water-soluble reducing compounds and percentag e inhibition of lipid oxidation of peel extracts, increased concentrat ions of a-tocopherol, carotenoids, and ascorbic acid in peel, but only slightly reduced scald. Delayed harvests increased all of these antio xidants except ascorbic acid and greatly reduced scald development. Ba gging fruit before ripening decreased cr-tocopherol, carotenoid, and a scorbic acid concentrations, decreased total water-soluble reducing co mpounds, and increased scald development. We conclude that changes in these antioxidants probably are affected more by ripening and light in tensity than by low temperature before harvest. Chemical name used: (2 -chloroethyl)phosphonic acid (ethephon).