The degradation of anthocyanins and ascorbic acid in black currant nectar was studied during processing and storage. A continuous production process was used where the nectar was bottled within 4.0h; 20 % of both components were lost in the main stream process. The choice of enzyme mainly affected the recovery of ascorbic acid. Pasteurization resulted in a loss of 2-6 % of the ascorbic acid content. About 50% of the original content of monomeric anthocyanins remained after 6 months storage at 208C. The stabilities of delphinidins and cyanidins during storage were very similar. Deaeration of the nectar before bottling had no effect on anthocyanin content.

Aroma changes during processing of black currant nectar were examined both by the dynamic headspace trapping technique and by sensory evaluation. Pasteurized and enzyme-treated nectars were compared with control nectar. Significant differences were found for 13 aroma compounds, of which 10 were subsequently identified. Nine of the identified compounds were esters, and eight of these decreased in quantity during enzyme treatment. Additionally, a total of 14 terpenes or terpenols were identified, and only one of these changed significantly in concentration during enzyme treatment. Pasteurization caused only minor changes in the concentration levels of the volatile compounds. GC-sniffing was used to estimate the potency of individual aroma compounds; the fruit esters as well as the terpenoids were apparently significant contributors to the aroma of black currant nectar. Keywords: Aroma; juice; enzymation; pasteurization; black currant