Solvent and Rotating Bed Reactor Extraction with One- and Two-Phase Solvents Applied to Bilberries ( Vaccinium myrtillus ) for Isolating Valuable Antioxidants

Extraction of antioxidants from bilberries using solvent extraction and the novel rotating bed reactor (RBR) both with one-phase (ethanol and water) and two-phase (ethanol and water +salt) solvents was studied. Solids, ethanol, and temperature settings in an experimental design were monitored for 1 h. The measured responses were (1) polyphenol concentration, (2) visible-near infrared spectra, and (3) HPLC measurement. The (1) responses were used for making response surfaces in time and the spectra (2) could confirm these results. The HPLC results (3) confirmed the results of 1 and 2 but were found unsuitable for online monitoring. The RBR was better than traditional extraction and 16 min sufficed. The response surfaces showed an optimal concentration of ethanol, temperatures above 50 °C gave the best results, and high loads of solid were beneficial. Two-phase extraction was less efficient. The methodology could be transferred to larger scale extraction systems to improve yield and save on reagents/energy cost.