Effect of pre-treatment of blue honeysuckle berries on bioactive iridoid content.

The aim of the study was to evaluate the effect of the different methods of preparation of the blue honeysuckle (Lonicera caerulea L. var. Kamtschatica) cv. 'Wojtek' and their influence on the iridoid content of fruit juices and fresh and freeze-dried pomaces. Compounds were identified by UPLC-ESI-qTOF-MS/MS in negative ion mode. Five iridoids - loganic acid, 7-epi-loganic acid 7-O-pentoside, loganin, sweroside, and secologanin - were determined in blue honeysuckle fruits and products. The results revealed no differences in iridoid content between the fresh pomace from skin and flesh, or between the juice from skin and flesh. A higher content of iridoids was obtained in juice from crushed than from whole berries, and in freeze-dried pomace from whole than from crushed berries. Freeze-dried pomace from blue honeysuckle can be an excellent source of bioactive iridoids.