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 lightis reflected and scattered at its surface, and this is partlydetermined by the form of the surface waxes. The fine fibrilspredominating on the surface of plums scatter light much morethan the platelets present on apples and pears, and cause thecharacteristic and prominent bloom. Polishing crushes the wax elements together, giving a much smootherreflecting 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 duringthe ripening of some varieties of apple.