Effects of cultivar, yield, berry weight, temperature and ripening stage on bioactive compounds of black currants

Abstract

Total anthocyanin, total phenols, ascorbic acid, antioxidant capacity (TEAC) were quantifi ed in fruit juice of 23 black currants cultivars grown at Geisenheim (lat. 49.6°), Germany, in the years 2003-2005. In addition, yield and 100-berry weight were recorded. There were remarkable variations in the phytochemical contents within the cultivars: 2.1-fold for TEAC and total phenols, 3.4-fold for total anthocyanins and even 4.4-fold for ascorbic acid. These differences are genetically determined but also signifi cantly modifi ed by plant physiology and environmental factors. The analysed compounds were negatively correlated with yield and 100 berry weight (TEAC: r = -0.34 and -0.43; total phenols: r = -0.34 and -0.48) while anthocyanins showed a signifi cant negative relationship only with the 100- berry weight (r = -0.38). In contrast, TEAC, total phenol and total anthocyanin were signifi cantly positive correlated with the temperature during the fruit developing phase, expressed as degree days (TEAC: r = 0.36, total phenols: r = 0.33 and total anthocyanins: r = 0.51, respectively). The ascorbic acid content was neither infl uenced by the plant parameters yield and 100-berry weight nor by degree days. There were also remarkable yearly changes of the analysed parameters within individual cultivars caused by low yield in 2004.