Analysis of the volatile compounds in acerola vinegar by solid-phase microextraction techniques coupled with gas chromatography-mass spectrometry

Abstract

Vinegar is derived from the conversion by bacteria of ethanol to acetic acid. It can therefore be produced from any alcoholic material, ranging from alcohol–water mixtures to wines. The aim of this work was to characterize the volatile composition of a vinegar of good and acceptable quality prepared from acerola wine. The volatile constituents of acerola vinegar were isolated by headspace solid-phase microextraction and analyzed by gas chromatography with flame ionization and selective mass detectors. A fiber of Carboxen-polydimethylsiloxane was used for the isolation of volatile compounds with optimized parameters: aliquot (8 mL) of vinegar with 1 g NaCl in a 15-mL vial. The sample was equilibrated at 45°C for 10 min and extracted with the fiber for 30 min under stirring at 500 min-1. A total of 69 volatile compounds, including 20 acids, 19 esters, 6 alcohols, 6 terpenes, 5 aldehydes, 3 n-paraffins, 2 ketones, 1 sulfur-containing compound and other 7 of different chemical nature were identified in acerola vinegar. The major constituents found in vinegar volatiles were acetic acid, 3-methylbutanoic acid and 2-phenylethyl acetate.