Relation between volatile composition, ellagitannin content and sensory perception of oak wood chips representing different toasting processes

Abstract

The evolution of both volatile and nonvolatile (ellagitannins) compounds extracted from oak wood chips while being macerated for 3 months in wine model solution with eight different commercial chips [Toasted LT (Light Toast), LT+ (Light plus Toast), MT (Medium Toast), MT+ (Medium plus Toast), HT (Heavy Toast), Noisette, Special) and un-toasted (UN)] was studied. Sensory analysis concerning vanilla, spicy, overall woody, astringency, bitterness and sweetness descriptors was conducted in parallel. A 2-month time is needed for the maximum extraction of ellagitannins and of furfural compound. Relating to other volatile compounds, their concentration increased progressively over time. Spicy, woody and vanilla aromas as well as sweetness perception increased during contact time with oak wood. Additionally to pyrolytic toasting stage, watering process during toasting influences significantly oak wood composition (lactones, vanillin guaiacol compounds and ellagitannins). Correlation analysis between chemical and sensory data demonstrated significant correlations between chemical and sensory parameters and provides some insight into the implication of volatile and nonvolatile composition on the final quality perception of astringency. A predictive model between astringency intensity and ellagitannins, furfural, guaiacol and methyl guaiacol contents was established. Ellagitannins levels explained 45 %, guaiacol and methyl guaiacol contents interpreted 13.20 and 8.86 %, respectively, whereas furfural levels justified 5.66 % of the total astringency variance.