The Fine Structure of Apple, Pear, and Plum Fruit Surfaces, their Changes during Ripening, and their Response to Polishing

The appearance of a fruit depends upon the way in which light is reflected and scattered at its surface, and this is partly determined by the form of the surface waxes. The fine fibrils predominating on the surface of plums scatter light much more than the platelets present on apples and pears, and cause the characteristic and prominent bloom. Polishing crushes the wax elements together, giving a much smoother reflecting surface, and sometimes the wax layer completely recrystallizes. The bloom, however, begins to regenerate within a few days, but it does not attain its original prominence. Changes comparable with those caused by polishing occur during the ripening of some varieties of apple.