Chemical profile of black currant fruit modified by different degree of infection with black currant leaf spot

Sugars, organic acids, vitamin C, individual phenolic compounds and total phenolic content were determined in fruit of 23 black currant cultivars with a different degree of infection caused by black currant leaf spot ( Drepanopeziza ribis ) and septoria leaf spot ( Septoria ribis ) using HPLC analysis. Glucose and fructose were the most abundant sugars and the major organic acids were malic and citric acid. Four anthocyanin aglycones were identified in different black currant cultivars, i.e. cyanidin, delphinidin, petunidin and peonidin; their content was genetically dependant. Cultivars ‘Brödtorp’, ‘Goliath’, ‘Pamyat Michurina’ and ‘Altajskaja Desertnaja’ had the lowest infection rates (less than 5%) with spot diseases in both consecutive years (2011 and 2012) and can therefore be classified as resistant black currant cultivars. Generally, cultivars with severe symptoms of leaf spot infection also contained lower levels of total analyzed sugars in their fruit. High levels of hydroxycinnamic acids, epicatechin, and myricetin, kaempferol and quercetin glycosides were detected in cultivars with minimal symptoms of leaf spot infection. Cultivars with parental origin of the ‘Goliath’ and ‘Brödtorp’ types were classified as D. ribis and S. ribis resistant and cultivars of ‘Baldwin’, ‘Boskoop Giant’, ‘Westra’ and ‘Victoria’ group were leaf spot susceptible.