Changes in chemical composition during ripening of Actinidia kolomikta fruits

Abstract

Fruits of the Actinidia genus are attributed to a fruit group with critical maturation period. Therefore is very important to identify fruits picking time which determines the persistence and qu-ality of the fruit. In Lithuania A. kolomikta fruits should be picked during the technical maturity phase because they get soft rapidly. The purpose of this work was to investigate changes in chemical com-position of A. kolomikta fruits during maturation period. Four cultivars of Actinidia kolomikta fruits – ‘Landė’, ‘Paukštės Šakarva’, ‘Laiba’ and ‘Lankė’ – were investigated. Fruits were picked three times in two-day intervals: first – August 11, second – August 13, and third – August 15. Picked fruits were ripened four days at 20±2° C temperature in room, pour a thin layer. Was analysed fruits chemical composition during ripening on plant, fresh fruits of all pickings and fruits after two and four days of ripening in room temperature. The amount of dry matter was determined by drying the samples to the constant mass at the temperature of 105 ºC, of soluble solids – by refractometric method and of ascorbic acid – by titration with 2.6-Dichlorphenolindophenol sodium salt dihydrate. The investi-gation showed that during ripening period content of dry matter and soluble solids increases while the content of ascorbic acid decreases. The biggest amount of dry matter accumulated in fruits of Actinidia kolomikta picked 62+4 days after the most abundant flowering and ripened at 20±2° C tem-perature four days. Such fruits must remain in good condition the longest and are best suited for drying, jams making, etc. The biggest amount of soluble solids was in fruits picked 62+2 days after the most abundant flowering and ripened at 20±2° C temperature four days. These fruits have the best taste characteristics for fresh consumption and freezing

The highest amount of ascorbic acid accumulated in the fruits of first picking after two days of ripening at 20±2° C temperature