Evaluation of aroma differences between high-salt liquid-state fermentation and low-salt solid-state fermentation soy sauces from China

Two types of Chinese soy sauce, high-salt liquid-state fermentation soy sauce (HLFSS) and low-salt solid-state fermentation soy sauce (LSFSS), were used to investigate their differences in aroma profile by headspace solid-phase microextraction (HS-SPME) and gas chromatography-olfactometry/mass spectrometry (GC-O/MS). Results from descriptive sensory analysis showed that the alcoholic, cooked potato-like and caramel-like attributes were significantly higher in HLFSS, while LSFSS exhibited significantly higher sour and burnt attributes. In addition, aroma extract dilution analysis (AEDA) revealed 37 and 33 odour-active regions for HLFSS and LSFSS, respectively. Ethanol, 3-methyl-1-butanol, phenylacetaldehyde, 4-ethyl-2-methoxyphenol, 2-methoxy-4-vinylphenol and 3-(methylthio)propanal detected in HLFSS showed the highest flavour dilution (FD) factors, while 3-methylbutanal, phenylacetaldehyde and ethyl propanoate possessed the highest FD factors in LSFSS. Therefore, the traditional Chinese soy sauce HLFSS contained more complex volatiles and exhibited a richer aromatic profile compared with LSFSS.