Metabolite profiling of doenjang, fermented soybean paste, during fermentation.
BACKGROUND
A fermented soybean paste known as doenjang is a traditional fermented food that is widely consumed in Korea. The quality of doenjang varies considerably by its basic ingredients, species of microflora, and fermentation process. The classification of predefined metabolites (e.g. amino acids, organic acids, sugars and sugar derivatives, and fatty acids) in doenjang samples according to fermentation was performed by using GC-FID and GC-MS data sets with the application of a multivariate statistical method.


RESULTS
The predominantly produced amino acids included alanine, valine, leucine, isoleucine, proline, glutamine, phenylalanine and lysine, showing remarkable increases in amounts during the later stages of fermentation. Carbonic acid, citric acid, lactic acid and pyrogultamic acid were identified as the major organic acids. Significant amounts of erythrose, xylitol, inositol and mannitol were detected during fermentation. Regarding fatty acids, relatively higher amounts of palmitic acid, stearic acid, oleic acid, linoleic acid and linolenic acid were found in the doenjang at each fermentation time point. Principal component analysis (PCA) successfully demonstrated changes in composition patterns as well as differences in non-volatile metabolites according to fermentation period.


CONCLUSIONS
A set of metabolites could be determined representing the quality of doenjang during fermentation, and which might also be correlated with taste ingredients, flavour, nutrition, and physiology activities that are claimed to be dependent on the quality control of commercial doenjang.
Namgung
Hye-Jung
HJ
Department of Food Science and Technology, Ewha Woman's University, 11-1 Daehyun-dong, Seodaemun-gu, Seoul 120-750, South Korea.
Park
Hye-Jung
HJ
Cho
In Hee
IH
Choi
Hyung-Kyoon
HK
Kwon
Dae-Young
DY
Shim
Soon-Mi
SM
Kim
Young-Suk
YS
D000143:Acids / Q000032:analysis*; D000596:Amino Acids / Q000032:analysis*; D001419:Bacteria / Q000378:metabolism; D004041:Dietary Fats / Q000032:analysis*; D019422:Dietary Sucrose / Q000032:analysis*; D005227:Fatty Acids / Q000032:analysis; D005285:Fermentation; D005516:Food Microbiology; D005658:Fungi / Q000378:metabolism; D055432:Metabolomics; D028321:Plant Preparations / Q000737:chemistry; D025341:Principal Component Analysis; D045730:Soy Foods; D013025:Glycine max / Q000737:chemistry* / Q000378:metabolism
D000143:Acids; D000596:Amino Acids; D004041:Dietary Fats; D019422:Dietary Sucrose; D005227:Fatty Acids; D028321:Plant Preparations