Effects of skin coatings on the behaviour of apples in storage. I. Physiological and general investigations.

Abstract

The effects of skin coatings on the physiological behaviour of apples have been investigated and a mechanism for the effects has been suggested. Using mainly the variety Granny Smith, the composition of the internal atmosphere, respiration rate, and other changes associated with ripening have been studied in both uncoated and coated apples. The effects were found to depend greatly on temperature, thickness and type of coating, and variety and condition of the fruits. Coating increased the resistance of the skin to gaseous diffusion and thus greatly reduced the internal oxygen concentration, increased the internal carbon dioxide concentration, reduced the respiration rate, and retarded ripening changes by varying degrees. The most spectacular effect on ripening was a marked retardation of normal yellowing of the skin, which is mainly controlled by internal oxygen supply.