Rapid determination of volatile flavor components in soy sauce using head space solid-phase microextraction and gas chromatography-mass spectrometry

A rapid and simple method was developed for the determination of volatile flavor components (VFCs) in soy sauce using head space solid-phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS). The effects of the conditions of HS-SPME, including types of SPME fibers, adsorption time, salt concentration, and extraction temperature, on the extraction of VFC were investigated. The optimized conditions were an 85 μm polyacrylate (PA) fiber, adsorption time of 40 min, temperature of 45°C, and NaCl concentration of 250 g/L. The concentrations of analytes were calculated on the basis of their relative peak areas to the internal standard of 2-octanol. It was demonstrated that this method had good reproducibility and satisfactory recoveries for the determination of common VFCs that were present in soy sauce. This method was applied to evaluate real samples, and it was found that alcohols, carboxylic acids, esters, and phenols were the major VFCs in soy sauce. Some oxo-compounds and heterocyclic compounds were also found in soy sauce.