Changes in fruit quality of highbush blueberries (Vaccinium corymbosum) during the ripening season

Abstract

This study illustrates variation in fruit quality attributes of two highbush blueberry cultivars ['Duke' and 'Bluecrop') across the harvests. Both cultivars were evaluated for their ripening time, physical fruit characteristics (fruit weight, index of fruit shape, and number of seeds fruit(-1)) and nutritional value (soluble solids content, total acids, total anthocyanin content, total phenolics and total antioxidant capacity). 'Duke' began to ripen 8 days earlier than 'Bluecrop' in both studied years (2013 and 2014), whereas the beginning of the ripening time was 2 days earlier in 2013. The mean fruit weight ranged from 1.87 g ['Duke') to 1.94 g ('Bluecrop') in 2013, i.e., from 1.86 g ('Bluecrop') to 1.94 g ('Duke') in 2014. Fruit weight of 'Bluecrop' decreased linearly from the first to fourth harvests and similar trend was observed in number of seeds fruit-1, while for 'Duke' trends of berry weight and number of seeds fruit-1 across harvests were inconsistent. The highest average amounts of soluble solids (SSC) and total acids (TA) in 2013 were detected in cultivar 'Bluecrop' (12.8 and 0.75%, respectively), but in 2014 SSC were similar between cultivars. TA varied greatly between the cultivars, whereby an opposite pattern to SSC can be observed across the harvests only in cultivar 'Duke' in both studied years. The differences in total anthocyanins between cultivars were statistically significant with higher value recorded in 'Duke', which also contained higher amount of total phenolics (TPH). Harvest had a significant effect on the TPH levels in 2013, but no significant differences in TPH were observed between the cultivars and harvest dates in 2014.