Flavor identification and analysis of fermented soybean pastes

Soybean paste is a staple food used to make doenjang (DE), cheonggukjang (CGJ), and miso (MI). In this study, solid-phase microextraction followed by gas chromatography-mass spectrometry was used to identify volatile components in DE, CGJ, and MI, and principal component analysis (PCA) was performed to determine their correlation between soybean pastes. Esters and hydrocarbons accounted for more than 55% of the total volatile components. PCA showed that esters were highly correlated with DE; pyrazines were correlated with CGJ; and alcohols were highly correlated with MI. Because DE, CGJ, and MI are made of the same material, their overall volatile content tended to be similar. However, the main volatile components and fragrances were different. These findings will be used as basic research data to promote quality improvement of soybean-based fermented foods in Korea and Japan.