INFLUENCE OF CUTICULAR STRUCTURE ON THE APPEARANCE OF ARTIFICIALLY WAXED DELICIOUS APPLE FRUIT

Irregularities in cuticle structure were studied in relation to finish quality of cultivar 'Delicious' apple fruit (Malus domestica Borkh.). The undisturbed cuticle surface was covered by wax platelets visible with scanning electron microscopy as a film on the fruit surface. Polishing this surface disrupted the wax and revealed the contour of the underlying structure. A reticulate pattern of cracks that deeply penetrated the cuticle often occurred near the calyx end of the fruit. This irregular nature of the cuticle appeared to be related to the poor appearance of some artificially waxed fruit. The cuticle on the equatorial and pedicel regions of the fruit had less cracking and appeared smooth and planar after polishing in spite of minor scratches. Cuticular cracks occasionally extended over the entire fruit surface. Application of a commercial wax filled in the scratches caused by polishing and improved fruit finish. The wax, however, did not always completely fill in the cracks and other irregularities that caused poor finish quality, therefore the commercial problem was not completely solved. © 1990.