Phenolic compounds in black currants of three Finnish cultivars and their response to growth latitude and weather conditions were analyzed over a six-year period. 'Melalahti' had lower contents of total phenolic compounds (31.4% and 29.2% lower than 'Mortti' and 'Ola', respectively), total anthocyanins (32.6% and 30.5%), and total hydroxycinnamic acid derivatives (23.1% and 23.8%) (p < 0.05) and was less affected by growth latitude and weather conditions than 'Mortti' and 'Ola'. However, all the cultivars grown at higher latitude (66°34' N) had lower contents of total flavonols, total anthocyanins, and total phenolic compounds than those grown at lower latitude (60°23' N) (p < 0.05). The content of total hydroxycinnamic acid conjugates did not vary in 'Melalahti' (p > 0.05) but increased as the latitude increased in 'Mortti' and 'Ola' (p < 0.05). Temperature and radiation were the major weather variables influencing the composition of phenolic compounds. Delphinidin-3-O-glucoside, delphinidin-3-O-rutinoside, and myricetin-3-O-glucoside content showed positive correlations with temperature and radiation in all three cultivars. The study gives important guidelines for the selection of raw materials and growth sites as well as for the berry cultivation for commercial exploitation of black currant berries.

Fractionation of black currant ( Ribes nigrum ) by juice pressing, four ethanol extractions, ethanol evaporation, and supercritical fluid extraction was studied. Phenolic compounds, sugars, and acids of the fractions were analyzed by high-performance liquid chromatography and gas chromatography. Sensory properties of the fractions were studied using generic descriptive analysis. Most of the sugars and acids were located in the juice, whereas the majority of the phenolic compounds were in the press residue. Ethanol extracted nearly all of the phenolic compounds from the press residue, leaving only fibers and seeds. The juice was dominant in most of the sensory attributes, whereas the extracts were perceived as most astringent. Three flavonol glycosides [kaempferol-3-O-(6''-malonyl)glucoside, myricetin-3-O-galactoside, and an unknown kaempferol glycoside] were discovered to be the compounds especially contributing to astringency. Ethanol extraction appeared to be an efficient and simple way to isolate phenolic compounds from black currant juice press residue.

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