L-ascorbinsäure-und polyphenolgehalt sowie antioxidative kapazität von frischen stachelbeeren

A total of 10 gooseberry cultivars was analyzed for their content of ascorbic acid and polyphenols by means of HPLC and for their content of total phenolics (Folin-Ciocalteu method) as well as for their antioxidative capacity (TEAC value) using a photometric analyzer. We also analyzed the influence of ripening on these parameters in the varieties 'Achilles', 'Bekay', and 'Xenia'. The results show that 'Bekay' and 'Rote Triumph' contain the highest amounts of ascorbic acid. During ripening a constant increase in ascorbic acid and polyphenol concentration was found. The main part (> 70 %) of the polyphenolic fraction in red gooseberry cultivars is due to anthocyanins consisting of a considerably high amount of acylated compounds (11 to 33 % of anthocyanins). Green cultivars show a reduced content of total phenolics as compared to the latter. Their phenolic constitution is attributed to relatively high amounts of hydroxycinnamic acid deri-vatives and flavanols. Thus, high polyphenol contents and antioxidative capacities are only found in small, red colou-red berries. These cultivars show TEAC values comparable to red currant.