Effects of skin coatings on the behaviour of apples in storage. III. Cool storage investigations.

Abstract

The effects of skin coatings on several varieties of apples during cool storage were studied in several seasons from 1941 to 1946. Most of the work was done with the Granny Smith and Jonathan varieties and coatings tested included alcoholic solutions of castor oil and shellac (C.O.S.), oil emulsions, and wax emulsions. With most varieties the more successful coatings, under favourable conditions of fruit maturity and of temperature before and after storage, reduced wastage and retarded loss of condition. The most successful coating, a 7-10 per cent. C.O.S. solution, increased commercial cold-storage life of a number of varieties by 25-30 per cent. C.O.S. and some oil coatings controlled superficial scald, but to a less degree than good oiled wraps. Most coatings controlled Jonathan spot and senescent disorders, but only the alcoholic solutions reduced mould wastage. Coatings at times caused direct injury to the fruit, but under favourable conditions this was usually not of commercial significance. Skin blemishes, internal disorders, and off-flavours were often severe in coated apples exposed to temperatures above 700°F either before or after cool storage. Wrapping in either plain or oiled wraps improved the out-turn of coated fruit.