An investigation of biochemical changes effected in early and late ripening of apricot fruits

In this study the biochemical changes were researched, which occur in the ripening period of the fruits in the early and late ripening five apricot varieties. In the early ripening varieties Canino, Turfanda-Eskimalatya and Hasanbey and in the late ripening Levent and Özal were taken the unripe, half ripe and ripe fruit samples in three different time periods; and in these sample fruits were analyzed the total soluble solids (TSS), titratable acidity, fruit firmness, the surface values in L a b and the growing periods of the fruits. In addition, the pectin methylesterase and polygalacturonase enzyms and total carotenoid chlorophyll a, chlorophyll b and total chlorophyll amount, their types and their changes in the ripening period were determined. In this study the Hacıhaliloglu variety was taken as testing sample, which is being grown widely in the Malatya-surroundings. The shortest fruit ripening time was found in Turfanda-Eskimalatya (84 days) and the longest in the Özal and Levent varieties (Özal 172 days, Levent 188 days). The total soluble solids showed a rapid increasing in the ripening period whereas it was low in the unripe and half ripe period. In the aspect of the titratable acidity the differences were found among the sorts and their ripening periods, the highest acidity was analyzed in the half ripe period. The acid amount decreased towards the fruit harvest quickly. Similarly the fruit firmness decreased in the late ripening periods which was high in the unripe and half ripe periods. Related to the fruit ripening period it was determined that the activities in the pectin methylesterase and polygalacturonase enzymes increased from the unripe period towards the ripe period. Among the sorts the highest PME and PG activity was found in the Hacıhaliloglu and the lowest PME activity in the Turfanda Eskimalatya and the lowest PG activity was found in Ozal varieties. With the ripening of the apricot fruits it was found that the amounts of chlorophyll a, chlorophyll b and the total chlorophyll were decreased considerably. Carotenoid rate decreased in the sorts of Hacıhaliloglu, Ozal and Turfanda Eskimalatya whereas it increased in the varieties of Levent and Canino during the ripening period.