Changes in sugar, organic acid, flavonol and carotenoid composition during ripening of berries of three seabuckthorn (Hippophae rhamnoides L.) cultivars

Soluble solid, sugar, organic acid, flavonol and carotenoid content were determined in seabuckthorn berries of the three German cultivars Askola, Hergo and Leikora, collected at different harvesting times, to provide a more thorough knowledge of quality changes occurring during ripening of the berries. The main organic acids were malic (1940-4660 mg/100 g), quinic (810-2820 mg/100 g), ascorbic (180-370 mg/100 g) and citric acid (90-160 mg/100 g). In all three cultivars a marked decline in total organic acid concentration was observed during ripening. The pattern of variation of sugars, glucose (0.26-2.10 g/100 g) and fructose (0.14-0.54 g/100 g), was somewhat different among the three cultivars. In all three cultivars ascorbic acid concentration decreased during ripening. The main flavonols were isorhamnetin (350-660 mg/kg), quercetin (30-100 mg/kg) and kaempferol (2-5 mg/kg). The trends of flavonol content during ripening were quite different among the three cultivars. The main carotenoids were zeaxanthin (30-150 mg/kg), beta-carotene (3-50 mg/kg) and beta-criptoxanthin (5-19 mg/kg). The genotype seemed to affect both the extent of carotenoid accumulation and the carotenoid profile but in all three cultivars ripening was accompanied by an increase in total carotenoid concentration. The various classes of antioxidants showed quite different patterns of variation during ripening, achieving their maximum level at different harvesting dates.