Analysis of Volatile Aroma Components in Fermented Soy Sauce

Head space solid-phase micro extraction(HS-SPME) and gas chromatography-mass spectrum(GC-MS) are applied to investigate the differences of volatile components in four original soy sauce and two commercial soy sauce,which are fermented by different brewing process.The results show that the dominating differences between the low-salt solid-state and high-salt and dilute-state soy sauce are alcohols,acids and esters among the detected 56 volatile components.The alcohols such as ethanol and isoamyl alcohol detected in high-salt and dilute-state soy sauce have higher acid components than that in low-salt and solid-state soy sauce.Both ethyl acetate and long chain fatty acid esters are the preponderance components in high-salt and dilute-state soy sauce,as well as 4-ethylguaiacol is the dominant aroma component.Phenylethanol and 5-methyl-2-phenyl-2-hexenal are the dominant aroma components in low-salt and solid-state soy sauce.PCA of the detected 56 volatile components shows that the discrimination based on HS-SPME/GC-MS and multivariate analysis is a powerful tool for characterizing and discriminating the characteristics of aroma components in different soy sauce.