Metabolomic analysis of extracts of Cheonggukjang was carried out using 1H nuclear magnetic resonance (NMR) spectrometry and principal components analysis (PCA). The major peaks in the 1H NMR spectra of the 50% methanol fraction were assigned to isoleucine/leucine, lactate, alanine, acetic acid, citric acid, choline, fructose, sucrose, tyrosine, phenylalanine and formic acid. The first two principle components (PC1 and PC2) of the 1H NMR spectra of the aqueous fraction allowed discrimination of Cheonggukjang extracts of samples obtained after different periods of fermentation. These two principal components cumulatively accounted for 98.5% of the total variation of all variables. The major peaks within the 1H NMR spectra that contributed to discrimination of different samples were assigned to isoleucine/leucine, lactate, acetic acid, citric acid, choline, fructose, glucose and sucrose. This metabolomic analysis of samples of Cheonggukjang extract demonstrates that NMR and PCA can be used to obtain standard trajectory plots and related information for Cheonggukjang and other fermented foods.
Bibliographical noteFunding Information:
This work was supported by research grants from Korea Science and Engineering Foundation (KOSEF) for Biofoods Research Program, Ministry of Science and Technology, Republic of Korea.
- H NMR
- Metabolomic analysis
- Principal component analysis