Biogenesis of Blackcurrant (Ribes nigrum) Aroma

The terpene fraction of blackcurrants is largely responsible for its characteristic flavour and aroma. The biogenesis of terpenes present in blackcurrant fruit has been studied by analysis of the volatile oils during ripening of the fruit and by feeding experiments using (2-13C) mevalonate. Three blackcurrant cultivars, Ben Lomond, Baldwin and Wellington XXX were studied, Ben Lomond and Baldwin fruit showed very similar composition of terpene compounds, whereas in Wellington XXX fruit, the terpenes derived from the thujane skeleton were at greatly reduced levels. Changes in concentration of monoterpene hydrocarbons, alcohols and esters occurred mainly during the period of sugar accumulation, when a sharp decrease in the level of terpene hydrocarbons and an increase in monoterpene alcohols and esters was observed. Feeding experiments with (2-13C) mevalonate indicated parallel incorporation into all monoterpene hydrocarbons and monoterpene alcohols. The presence of monoterpene and aromatic glycosides have also been tentatively identified in blackcurrants for the first time.