Comparison of headspace solid phase microextraction and XAD-2 methods to extract volatile compounds produced by Saccharomyces during wine fermentations

A modified headspace solid phase microextraction (HS-SPME) method was compared with Amberlite (R) XAD-2 resin for the extraction of volatile compounds. In the HS-SPME method, volatiles were extracted using an 85 mu m polyacrylate fiber from wines that contained a standardized amount of ethanol (10% v/v), NaCl (0.325 g/mL) and internal standards (dodecanol and nonanoic acid). Both extraction procedures yielded high relative recoveries (> 92%) and reproducibilities (coefficient of variations <= 11%) for the different higher alcohols, esters and medium-chain fatty acids. Overall, limits of detection for the HS-SPME and XAD-2 methods were below sensory threshold concentrations. HS-SPME and XAD-2 performed similarly in the analysis of a Riesling wine; however, the HS-SPME method did not require organic solvents and was generally quicker to perform. In applying the HS-SPME method, differences in concentrations of volatile compounds produced in Riesling and Chenin blanc wines by 11 different yeast strains were noted.