INFLUENCE OF CALCIUM DIPS ON BIOSYNTHESIS OF AROMA VOLATILE COMPOUNDS IN 'FUJI KIKU-8' APPLES

‘Fuji Kiku-8’ apples, harvested at commercial maturity, were dipped in calcium chloride (2% w/v) and stored at 1°C and 92% RH for 4 or 7 months under air plus 7 days at 20°C. The calcium concentration was higher in treated fruit, showing that the treatment was effective in introducing calcium into the tissues. In general, calcium treatment led to enhanced production of those aroma volatile compounds considered to have an impact on overall flavour of ‘Fuji Kiku-8’ apples cold-stored for 4 months. Higher aroma volatile emission in calcium-treated fruit possibly arose from enhanced supply of precursors for ester production as a consequence of increased pyruvate decarboxylase (PDC) and alcohol dehydrogenase (ADH) activities. This effect was not so apparent after long-term storage periods. After 7 months of cold storage, higher levels of aroma volatile compounds emitted by calcium-treated apples could have arisen from increased alcohol o-acyltransferase (AAT) activity. Moreover, consumer acceptability was higher in calcium-treated samples, thus suggesting that calcium treatments, apart from having beneficial effects on aroma volatile compounds production, may be useful for improving sensory quality of cold-stored ‘Fuji Kiku-8’ apples.