Recovery of volatile aroma compounds from black currant juice by vacuum membrane distillation

This study evaluated the recovery of seven characteristic black currant aroma compounds by vacuum membrane distillation (VMD) carried out at low temperatures (10-45 degreesC) and at varying feed flow rates (100-500 l/h) in a lab scale membrane distillation set tip. VMD at feed flow from 100 to 500 l/h at 30 degreesC gave concentration factors, calculated for each aroma compound as C-permeate/C-feed: from similar to4 to 15. The concentration factors increased with decreased juice temperature during VMD; at 10 degreesC concentration factors of 21-31 were obtained for the highly volatile aroma esters. The recovered levels of the highly volatile aroma compounds ranged from 68 to 83 vol.% with a feed volume reduction of 5 vol.% (10 degreesC, 400 l/h). The theoretically predicted aroma recovery as a function of the feed volume reduction was in accordance with the experimentally obtained values. VMD thus turned out to be a promising technique for gentle stripping of black currant juice aroma compounds.