VOLATILE COMPOUNDS IN GOLDEN DELICIOUS APPLE FRUIT (Malus domestica) DURING COLD STORAGE

Biosynthesis of volatile compounds (VC), as well as activity of related enzymes (lipoxygenase LOX, alcohol acyltransferase AAT, and alcohol dehydrogenase ADH), and fatty acids (palmitic, stearic, oleic, linoleic and linolenic acids) were assessed in Golden Delicious fruit apples (Malus domestica Borkh.) during 1 degrees C storage at different atmosphere conditions. Three atmosphere conditions were used: 21 % O-2 and > 1 % CO2 (Regular Atmosphere, RA), 3 % CO2 and 2 % O-2 (Controlled Atmosphere, CA), and CA, with 7 d under RA conditions (CA + RA), to evaluate the effect of shorts periods under air storage. CA conditions inhibited the production of butyl acetate and hexyl acetate esters, and increased hexanol concentration. Production of the branched ester 2-methyl butyl acetate did not decrease under CA conditions. As a result of 7 d under RA, butyl acetate and hexyl acetate in CA + RA increased, mainly after one month of storage. Storage under CA conditions inhibited LOX and AAT activity at some stages whereas ADH activity increased during CA storage. LOX activity showed high correlation with production of aldehydes (r(2) = 0.85) and cis-2-hexenal (r(2) = 0.94), during storage of apples under CA conditions. Good correlation was found between AAT activity and total esters and butyl acetate content under CA storage of apples (r(2) = 0.92 and r(2) = 0.93, respectively). While most fatty acids increased in concentration during RA and CA storage, linolenic acid content decreased. No correlation between volatile compounds content and fatty acid production was found.