Changes in fruit quality in black chokeberry (Aronia melanocarpa) during maturation

Black chokeberry fruits are rich in anthocyanins and can be used as a raw m aterial for the production of natural food colourants. Fruit quality was st udied during maturation in three true black chokeberry cultivars and in thr ee cultivars derived through hybridization between chokeberry and rowans (S orbus spp.). For each trait studied, the three black chokeberry cultivars w ere very similar. The three hybrid cultivars differed however from the blac k chokeberry cultivars for some traits in both tinting and size of the resp onse which indicates that cultivar selection for improvement of fruit quali ty can hardly be done among the true black chokeberry genotypes but may be efficient when the hybrid cultivars are also included. For the black chokeb erry cultivars, maximum berry weight was reached already by the 22 August. Anthocyanin content increased by 180% during the period mid-August to mid-S eptember. Meanwhile, the content of undesirable brown compounds increased b y 100%. The content of malic acid remained unchanged whereas total acidity decreased in the initial part of the study period. Variation among sampling dates in total acidity was negatively correlated with variation in berry w eight which suggests that dilution by water uptake affects total acidity. F or the true black chokeberry cultivars, optimal harvest date was determined to be 8 September for this trial, when both mean berry weight and anthocya nin content had reached their maximum. By harvesting one week earlier brown ing was reduced by 32% but with a simultaneous decrease in anthocyanin cont ent of 20%.