Volatile Compounds in Fermented and Acid‐hydrolyzed Soy Sauces

ABSTRACT: Volatile compounds in fermented and acid‐hydrolyzed soy sauces were isolated and analyzed using solvent extraction and solid‐phase microextraction. Quantitatively, alcohols and esters were dominant in the volatiles of fermented soy sauce, whereas heterocyclic compounds, including pyrazines and furans, and acids were relatively abundant in the acid‐hydrolyzed soy sauce. The odor‐active compounds were also evaluated. The major odor‐active compounds of fermented soy sauce were acetic acid, furfuryl alcohol, 2‐methoxyphenol, benzeneethanol, benzoic acid, butyric acid, 2‐ethyl‐4‐hydroxy‐5‐methyl‐3(2H) furanone, and 2‐methylbutanal, whereas acetic acid, 2‐methoxyphenol, formic acid, benzoic acid, 2,5‐dimethylpyrazine, 2,6‐dimethylpyrazine, butyric acid, 2,6‐dimethoxyphenol, 3‐hydroxy‐2‐methyl‐4H‐pyran‐4‐one, 2‐acetyl‐5‐methylfuran, 2,5‐dimethyl‐3‐ethylpyrazine, and 2‐methylbutanal constituted the major odor‐active compounds of acid‐hydrolyzed soy sauce.