Characteristic aroma compounds of cooked and fermented soybean (Chungkook-Jang) inoculated with various Bacilli

For selecting Chungkook-jang products with a less undesirable odour, the volatile compounds that affect the overall consumer acceptance of Chungkook-jang products were analysed. The volatile compounds of Chungkook-jang were extracted by using solid phase microextraction and direct solvent extraction and were detected by using gas chromatography-olfactometry. The results were represented as the mean of the log3 flavour dilution factors; principal component analysis was used to determine the effective components.

Fifteen and 14 volatile compounds were detected in the extracts using solid phase microextraction and direct solvent extraction, respectively. The Bacillus species 2-M1L, which has the most overall acceptance, might have a nutty initial top note and nutty and cheesy long-lasting note aromas. In correlation analysis between the characteristic aromas and the overall acceptance, trimethyl pyrazine (nutty, pungent), butanoic acid (cheesy, butyric), and methyl pyrazine (burnt, roasted) were positively correlated with overall acceptance. In contrast, 3-hydroxy-2-butanone (buttery, fatty) and 2,3-butanediol (chemical, fatty) were negatively correlated with overall acceptance.

Consumers might prefer Chungkook-jang that has a more nutty and cheesy flavour and a less fatty one.