Extraction of volatile aroma compounds from toasted oak wood using pulsed electric field

Abstract

The effect of pulsed electric field (PEF) on the extraction of volatile compounds from toasted oak wood chips immersed in various aqueous ethanol solutions (5%, 12%, 50%, and 70% vol/vol) was determined by Gas chromatography/mass spectrometry (GC/MS) after ultrasound-assisted extraction. PEF treatment showed the highest impact in the 5% solution, increasing vanillin, syringaldehyde, oak lactone (cis- and trans-), and furfural by 75%, 371%, 13%, and 50%, respectively. PEF was also tested on Agiorgitiko red wine and on malt and wine distillates. In wine distillate, 4-vinylguaiacol was also detected. For red wine, a PEF of 1.2 kV/cm increased the efficiency of extraction of wood aroma compounds from 5% to 200%. Differences in the extracted volatile compound concentrations between the control and PEF-treated samples were also observed in the malt and wine distillates. The sensory evaluation showed that the PEF-treated malt was similar to an aged whiskey, having nuances of toasted oak. Practical applications This work was done as a preliminary investigation for our on-going research into the application of PEF technique for the extraction of aromatic compounds from oak wood, and the acceleration of both wine and malt distillate aging. The findings suggest that PEF could be introduced in wine, brandy, and whiskey industry as a novel technology for the acceleration of the aging process.