Metabolomic-Based Comparison of Traditional and Industrial Doenjang Samples with Antioxidative Activities.

Song-Hui Soung,Seung-Hwa Lee,Choong-Hwan Lee,Sunmin Lee,Hae-Jin Kim,Na-Rae Lee

doi:10.3390/foods10061377

Abstract

Numerous varieties of doenjang are manufactured by many food companies using different ingredients and fermentation processes, and thus, the qualities such as taste and flavor are very different. Therefore, in this study, we compared many products, specifically, 19 traditional doenjang (TD) and 17 industrial doenjang (ID). Subsequently, we performed non-targeted metabolite profiling, and multivariate statistical analysis to discover distinct metabolites in two types of doenjang. Amino acids, organic acids, isoflavone aglycones, non-DDMP (2,3-dihydro-2,5-dihydroxy-6-methyl-4H-pyran-4- one) soyasaponins, hydroxyisoflavones, and biogenic amines were relatively abundant in TD. On the contrary, contents of dipeptides, lysophospholipids, isoflavone glucosides and DDMP-conjugated soyasaponin, precursors of the above-mentioned metabolites, were comparatively higher in ID. We also observed relatively higher antioxidant, protease, and β-glucosidase activities in TD. Our results may provide valuable information on doenjang to consumers and manufacturers, which can be used while selecting and developing new products.

Highlights

Doenjang, fermented soybean paste, has played an important role as a food ingredient and protein source in Korea for hundreds of years
The principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) score plot derived from GC-TOF-MS data represents that the metabolite profiles of traditional doenjang (TD) and industrial doenjang (ID) were clearly separated by PC1 (23.0%) and PLS1 (22.8%) (Figure 1A,C)
Doenjang differs extensively depending on the manufacturing process used and such variables as the fermentation microorganisms, fermentation period, and ingredients

Summary

Introduction

Doenjang, fermented soybean paste, has played an important role as a food ingredient and protein source in Korea for hundreds of years. Doenjang is made from meju, which is a fermented soybean lump. The meju is brined and fermented for several months, and separated into liquid and solid parts for further fermentation to produce soy sauce and doenjang (soy paste), respectively. The solid component is fermented for a few more months to years for maturing of the doenjang [10]. The fermentation leads to the enhancement of many nutritional metabolites (e.g., amino acids, fatty acids, organic acids, minerals and vitamins) [11] and bioactive metabolites (e.g., isoflavonoids and soyasaponins) in the doenjang through the degradation of ingredients. The metabolite contents in a variety of products are significantly distinguished due to many factors such as different fermentation microorganisms, fermentation periods, and ingredients [1]

Methods

Results

Conclusion