• Review article
• Open access
• Published: 23 September 2025 Journal of Ethnic Foods volume 12, Article number: 33 (2025) Cite this article

Abstract

Korean fermented soybean pastes (jang, including doenjang, ganjang, and gochujang) and jeotgal are characterized by their complex microbial ecosystems, rich nutrient composition, and notable health-promoting properties. These foods naturally generate bioactive metabolites such as isoflavones, γ-polyglutamic acid, phenolic acids, and peptides, which contribute to antioxidant, anti-inflammatory, anti-cancer, and menopausal symptom-alleviating effects. Unlike standardized industrial products, traditional fermentation relies on spontaneous microbial interactions and extended maturation, resulting in distinctive metabolite profiles and enhanced functional activity. Recent advances in metabolomics have enabled comprehensive characterization of these metabolites through both targeted and untargeted approaches, offering insights into fermentation dynamics, nutritional quality, and functional potential. Comparative metabolomic studies reveal that traditionally fermented soybean pastes and jeotgal exhibit greater chemical diversity and bioactivity compared with their commercial counterparts, emphasizing both their scientific and cultural value. This review synthesizes current evidence on the nutritional and functional attributes of these foods, with a focus on metabolomic methodologies that elucidate key metabolic pathways and their physiological relevance. In addition, it highlights the industrial potential of fermentation-derived bioactive compounds, while emphasizing the need for integrative multi-omics strategies, including genomics and metagenomics, to understand complex microbe–host–metabolite interactions. Such approaches can deepen understanding of how fermentation-derived metabolites contribute to host health, gut microbiota modulation, and disease prevention. By consolidating nutritional, functional, and metabolomic perspectives, this review provides a focused framework for advancing the global recognition, scientific validation, and sustainable development of Korean fermented soybean pastes and jeotgal.

Introduction

Korean traditional foods comprise a diverse array of fermented products and naturally derived ingredients that have evolved through centuries of cultural heritage and empirical knowledge. Notably, fermented foods such as kimchi, various forms of jang (soybean-based pastes and sauces), and jeotgal (fermented seafood products) are distinguished by their complex microbial ecosystems and bioactive compound profiles. These products are enriched with functional metabolites, including amino acids, vitamins, and antioxidant compounds, generated through microbial metabolism during fermentation, and are associated with a range of health-promoting effects, including gastrointestinal regulation, immune enhancement, and anti-inflammatory activity.

The raw materials utilized in traditional Korean foods are typically subjected to minimal processing, thereby preserving their native nutritional and biofunctional characteristics. In this context, metabolomics has emerged as a robust analytical platform for the comprehensive profiling of small-molecule metabolites, enabling the elucidation of fermentation-driven biochemical transformations and functional properties.

Recent advances in metabolomics have facilitated the in-depth characterization of traditional fermented condiments such as jang and jeotgal, revealing distinct metabolic signatures, microbial–metabolite interactions, and key bioactive constituents with physiological relevance. By linking metabolite profiles to functional outcomes, metabolomics provides a mechanistic bridge between traditional health claims and scientific validation, uncovering both known and novel bioactive compounds that contribute to health-promoting effects.

This review critically examines current metabolomics-based investigations into Korean fermented foods, highlighting their nutritional and functional potential while outlining future research priorities and translational prospects for functional food development and industrial innovation. Unlike previous reviews [[1](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR1 “Jung SJ, Chae SW, Shin DH. Fermented foods of Korea and their functionalities. Fermentation. 2022;8(11):645. https://doi.org/10.3390/fermentation8110645

.“), [2](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR2 “Lee HJ, Lee MJ, Choi YJ, Park SJ, Lee MA, et al. Free amino acid and volatile compound profiles of jeotgal alternatives and its application to kimchi. 2021. Foods. https://doi.org/10.3390/foods10020423

.“)] that focused on either specific fermentation experiments or the health benefits of fermented foods, our work emphasizes the integration of metabolomics to systematically analyze metabolite profiles and bioactive compounds. By synthesizing historical, sociocultural, nutritional, sensory, and metabolomics-related dimensions, this review provides a comprehensive perspective that was not fully covered in prior studies.

This review focuses on integrating nutritional and metabolomic insights to elucidate the health functionalities of traditional Korean fermented foods, with an emphasis on jang and jeotgal. To support this review, an integrative literature search was conducted using targeted keywords such as “Korean traditional food,” “jang,” “jeotgal,” “mass spectrometry,” and “metabolomics” in databases including PubMed and Google Scholar, covering literature published between 2000 and 2025. Titles, abstracts, and full texts were carefully screened to ensure the inclusion of high-quality and relevant studies.

Definition and scope of traditional Korean fermented foods

The concept and functional importance of fermentation in traditional Korean foods

Korean traditional foods represent a complex interplay of cultural heritage, regional diversity, and empirically refined culinary practices. Core examples include fermented foods such as doenjang, gochujang, ganjang, cheonggukjang, and kimchi, which are produced via spontaneous fermentation by indigenous microbial communities and remain central to the Korean diet [[3](#ref-CR3 “Das G, Heredia JB, de Lourdes PM, Coy-Barrera E, Rodrigues Oliveira SM, et al. Korean traditional foods as antiviral and respiratory disease prevention and treatments: a detailed review. Trends Food Sci Technol. 2021;116:415–33. https://doi.org/10.1016/j.tifs.2021.07.037

.“),4,[5](#ref-CR5 “Kim SH, Kim MS, Lee MS, Park YS, Lee HJ, et al. Korean diet: characteristics and historical background. J Ethnic Foods. 2016;3(1):26–31. https://doi.org/10.1016/j.jef.2016.03.002

.“),[6](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR6 “Park JE, Han A, Mun EG, Cha YS. A traditional Korean fermented food, gochujang exerts anti-hypertensive effects, regardless of its high salt content by regulating renin-angiotensin-aldosterone system in SD rats. Heliyon. 2024;10(9):e30451. https://doi.org/10.1016/j.heliyon.2024.e30451

.“)].

Fermentation, a biochemical process mediated by microorganisms, transforms macronutrients, such as carbohydrates, proteins, and lipids, into diverse metabolites, contributing to food preservation, flavor complexity, and nutritional enhancement. In traditional Korean foods, such processes occur under empirically optimized conditions rooted in historical practice [[7](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR7 “Gille D, Schmid A, Walther B, Vergeres G. Fermented food and non-communicable chronic diseases: a review. Nutrients. 2018;10(4):448. https://doi.org/10.3390/nu10040448

.“), [8](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR8 “Jayachandran M, Xu B. An insight into the health benefits of fermented soy products. Food Chem. 2019;271:362–71. https://doi.org/10.1016/j.foodchem.2018.07.158

.“)].

Particularly in jang (fermented soybean products) and jeotgal (fermented seafood), fermentation yields unique sensory qualities and compound profiles. Figures 1 and 2 illustrate representative types of jang (doenjang, ganjang, gochujang) and jeotgal (myeongranjeot, saeujeot, myeolchijeot), respectively. For jeotgal, subtypes include whole or paste-form products, liquid extracts such as aekjeot (fish sauce), and carbohydrate-supplemented types such as sikhae, reflecting the technological and microbial diversity inherent in Korean fermentation practices. These figures provide visual references that support the discussion of nutritional and functional properties of these fermented foods throughout the manuscript [[9](#ref-CR9 “D’Este M, Alvarado-Morales M, Angelidaki I. Amino acids production focusing on fermentation technologies - a review. Biotechnol Adv. 2018;36(1):14–25. https://doi.org/10.1016/j.biotechadv.2017.09.001

.“),[10](#ref-CR10 “Choi YJ, Jang MS, Lee MA. Physicochemical changes in kimchi containing skate (Raja kenojei) pretreated with organic acids during fermentation. Food Sci Biotechnol. 2016;25(5):1369–77. https://doi.org/10.1007/s10068-016-0214-4

.“),[11](#ref-CR11 “Gao Y, Hou L, Gao J, Li D, Tian Z, et al. Metabolomics approaches for the comprehensive evaluation of fermented foods: a review. 2021. Foods. https://doi.org/10.3390/foods10102294

.“),[12](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR12 “Cha YJ, Yu D. Health benefits and functions of salt-fermented fish. J Ethn Foods. 2024;11(1):34. https://doi.org/10.1186/s42779-024-00251-5

.“)].

Fig. 1 Representative types of Korean traditional jang (fermented sauces): A doenjang (fermented soybean paste), B ganjang (soy sauce), and C gochujang (fermented red pepper paste). Images (A) and (B) were provided by the Jeju Special Self-Governing Province, and image (C) was provided by the Korea Agro-Fisheries & Food Trade Corporation. All images are used under the Korea Open Government License (KOGL), Type 1 (Attribution), available at www.kogl.or.kr

Fig. 2 Representative types of Korean traditional jeotgal (fermented seafood): A myeongranjeot (salted pollock roe), B saeujeot (salted shrimp), and C myeolchijeot (salted anchovy). Image (A) was provided by the Busan Metropolitan City, (B) by the Chungnam Culture and Tourism Foundation, and (C) by the Academy of Korean Studies. All images are used under the Korea Open Government License (KOGL), Type 1 (Attribution), available at www.kogl.or.kr

Recent advances in omics technologies, especially metabolomics, provide scientific insights into microbial dynamics and metabolite formation in these foods, positioning fermentation as both a traditional preservation technique and a biotechnological process of modern relevance.

Nutritional value and bioactive compounds in traditional Korean fermented foods

Traditional Korean fermented foods are increasingly recognized for their functional potential, attributable to the bioactive compounds produced during microbial fermentation. These include a broad spectrum of metabolites such as organic acids, amino acids, phenolic compounds, γ-polyglutamic acid (γ-PGA), and various peptides with demonstrated antioxidant, anti-inflammatory, and anti-microbial activities [[13](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR13 “Özyalçin B, Sanlier N. The effect of diet components on cancer with epigenetic mechanisms. Trends Food Sci Technol. 2020;102:138–45. https://doi.org/10.1016/j.tifs.2020.06.004

.“)].

Fermentation facilitates the degradation of harmful substances and supports the proliferation of beneficial microbiota, thereby improving gut health and enhancing the overall nutritional profile of the food [[14](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR14 “Bell V, Ferrao J, Fernandes T. Nutritional guidelines and fermented food frameworks. Foods. 2017;6(8):65. https://doi.org/10.3390/foods6080065

.“), [15](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR15 “Tachie CYE, Onuh JO, Aryee ANA. Nutritional and potential health benefits of fermented food proteins. J Sci Food Agric. 2024;104(3):1223–33. https://doi.org/10.1002/jsfa.13001

.“)]. For instance, jeotgal fermentation under high-salt conditions fosters the growth of halotolerant bacteria such as Tetragenococcus spp., which are involved in the production of bioactive molecules including biogenic amines and short-chain fatty acids [[16](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR16 “Akther F, Le B, Chung G, Yang SH. Optimizing the fermentation condition of low salted squid jeotgal by lactic acid bacteria with enhanced antioxidant activity. J Appl Biol Chem. 2017;60(4):391–402. https://doi.org/10.3839/jabc.2017.060

.“)].

Moreover, proteolytic processes, driven by both endogenous and microbial enzymes, yield peptides and amino acids that contribute to both the sensory and health-promoting properties of fermented products [[2](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR2 “Lee HJ, Lee MJ, Choi YJ, Park SJ, Lee MA, et al. Free amino acid and volatile compound profiles of jeotgal alternatives and its application to kimchi. 2021. Foods. https://doi.org/10.3390/foods10020423

.“)]. For example, γ-PGA derived from Bacillus species in doenjang has shown antioxidant and antihypertensive effects in vitro and in vivo models. Isoflavones such as genistein and daidzein have demonstrated estrogenic and anti-cancer activities in cell-based assays and limited human trials. Similarly, peptides isolated from fermented soybean paste have shown ACE-inhibitory activity in animal studies. The accumulation of glutamic acid and other umami-related amino acids is particularly noteworthy in jeotgal, contributing to its distinct taste and functional profile [[17](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR17 “Jung JY, Han SS, Kim ZH, Kim MH, Kang HK, et al. In-vitro characterization of growth inhibition against the gut pathogen of potentially probiotic lactic acid bacteria strains isolated from fermented products. Microorganisms. 2021. https://doi.org/10.3390/microorganisms9102141

.“), [18](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR18 “Song EJ, Lee ES, Park SL, Choi HJ, Roh SW, et al. Bacterial community analysis in three types of the fermented seafood, jeotgal, produced in South Korea. Biosci Biotechnol Biochem. 2018;82(8):1444–54. https://doi.org/10.1080/09168451.2018.1469395

.“)].

Collectively, these features underscore the dual nutritional and functional significance of traditional Korean fermented foods, positioning them as promising candidates for evidence-based dietary strategies and functional food development [[19](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR19 “Kong H, Jeong DW, Kim N, Lee S, Sul S, et al. Safety and technological characterization of Staphylococcus xylosus and Staphylococcus pseudoxylosus isolates from fermented soybean foods of Korea. J Microbiol Biotechnol. 2022;32(4):458–63. https://doi.org/10.4014/jmb.2111.11040

.“)].

Major components and functional properties of jang and jeotgal

Biochemical changes during fermentation and associated microorganisms

Soybeans are rich in protein, making them a versatile base for a wide variety of food products. They are particularly valuable as sources of amino acids and peptides, enhancing both the nutritional value and flavor profile of fermented foods. In traditional Korean cuisine, soybeans are processed into meju, a dried and fermented soybean block, which serves as the foundational ingredient for staple fermented condiments such as soy sauce (ganjang), soybean paste (doenjang), and red pepper paste (gochujang).

Although soy sauce and soybean paste share an initial fermentation process, they are differentiated by their method of extraction: meju blocks are submerged in brine to undergo liquid-state fermentation, from which the liquid is collected as soy sauce, while the remaining solid residue is aged further to produce soybean paste. This fermentation process not only enhances the palatability of the products but also enriches them with bioactive compounds such as amino acids, peptides, and functional metabolites, thereby contributing to their health-promoting properties and establishing their value as traditional functional foods [[20](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR20 “Shin D, Jeong D. Korean traditional fermented soybean products: jang. J Ethnic Foods. 2015;2(1):2–7. https://doi.org/10.1016/j.jef.2015.02.002

.“)].

Traditional Korean fermented foods such as jang (doenjang, ganjang, gochujang) and jeotgal undergo a series of complex biochemical transformations during fermentation, which significantly influence their nutritional value, organoleptic properties, and functional attributes. These changes are primarily driven by the dynamic interactions among microbial communities that evolve over the course of fermentation [[21](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR21 “Han DM, Chun BH, Kim HM, Jeon CO. Characterization and correlation of microbial communities and metabolite and volatile compounds in doenjang fermentation. Food Res Int. 2021;148:110645. https://doi.org/10.1016/j.foodres.2021.110645

.“), [22](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR22 “Shukla S, Choi TB, Park HK, Kim M, Lee IK, et al. Determination of non-volatile and volatile organic acids in Korean traditional fermented soybean paste (Doenjang). Food Chem Toxicol. 2010;48(8–9):2005–10. https://doi.org/10.1016/j.fct.2010.04.034

.“)].

In the fermentation process of kimchi, the intake of various amino acids positively influences the growth and activity of lactic acid bacteria, enhancing the fermentation quality and stability. Specifically, salted fish not only enhances the flavor of kimchi but also serves as a major source of amino acids, while simultaneously promoting the production of functional metabolites, thereby increasing the health benefits and bioactive properties of kimchi [[23](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR23 “Jung MY, Kim TW, Lee C, Kim JY, Song HS, et al. Role of jeotgal, a Korean traditional fermented fish sauce, in microbial dynamics and metabolite profiles during kimchi fermentation. Food Chem. 2018;265:135–43. https://doi.org/10.1016/j.foodchem.2018.05.093

.“)].

In products like doenjang and ganjang, soybean proteins, rich in amino acids, are hydrolyzed by microbial proteases into peptides and free amino acids, which not only contribute to umami flavor but also exhibit various bioactivities such as antioxidant, antihypertensive, and anti-inflammatory effects. Carbohydrates are similarly degraded by amylolytic enzymes into simpler sugars, serving as substrates for fermentative metabolism that results in the production of organic acids, ethanol, and aroma compounds.

The microbial consortia involved in fermentation typically include species such as Bacillus spp., Aspergillus oryzae, Tetragenococcus halophilus, and Lactobacillus spp., each playing distinct roles in proteolysis, saccharification, acidification, and the biosynthesis of bioactive metabolites. In high-salt environments, halotolerant microorganisms are especially crucial for the stable fermentation of salted seafood products like jeotgal, where they contribute to both safety and flavor development through the production of specific metabolic by-products, including biogenic amines and free fatty acids [24].

These biochemical and microbial dynamics underscore the transformation of traditional fermented foods from mere seasonings to complex functional food systems. Recent advancements in omics technologies, particularly metabolomics and metagenomics, have enabled a more comprehensive understanding of the interplay between microbial populations and metabolite production, thereby providing a scientific basis for the health-promoting properties of traditional fermented products.

Evaluation of the probiotic properties of lactic acid bacteria isolated from high-salt fermented seafood, such as jeotgal, demonstrated that this traditional product serves as a valuable source for isolating probiotic strains capable of maintaining high cell viability under low pH conditions. These findings suggest the potential of jeotgal as a functional reservoir for robust probiotic candidates [[25](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR25 “Song NE, Kim NJ, Kim YH, Baik SH. Probiotic properties of lactic acid bacteria with high conjugated linoleic acid converting activity isolated from Jeot-gal, high-salt fermented seafood. Microorganisms. 2021. https://doi.org/10.3390/microorganisms9112247

.“)]. Fermented seafood products such as jeotgal are rich in free amino acids, particularly glutamic acid, as well as nucleotide-related compounds including adenosine triphosphate (ATP), adenosine diphosphate (ADP), and inosine monophosphate (IMP). These components significantly contribute to the umami flavor profile of jeotgal [[2](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR2 “Lee HJ, Lee MJ, Choi YJ, Park SJ, Lee MA, et al. Free amino acid and volatile compound profiles of jeotgal alternatives and its application to kimchi. 2021. Foods. https://doi.org/10.3390/foods10020423

.“)].

Physiological and functional health effects of Korea traditional fermented foods

Korean traditional fermented foods, particularly those derived from soybeans such as doenjang, ganjang, gochujang, and cheonggukjang, as well as fermented seafood products like jeotgal, are gaining increasing scientific interest for their potential role in preventing and managing chronic metabolic diseases. Despite their traditionally high-salt content, accumulating evidence suggests that these fermented foods exhibit a range of health-promoting properties, supported by findings from in vitro, in vivo, and clinical studies [[1](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR1 “Jung SJ, Chae SW, Shin DH. Fermented foods of Korea and their functionalities. Fermentation. 2022;8(11):645. https://doi.org/10.3390/fermentation8110645

.“), [26](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR26 “Toro-Funes N, Bosch-Fuste J, Latorre-Moratalla ML, Veciana-Nogues MT, Vidal-Carou MC. Biologically active amines in fermented and non-fermented commercial soybean products from the Spanish market. Food Chem. 2015;173:1119–24. https://doi.org/10.1016/j.foodchem.2014.10.118

.“), [27](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR27 “Dwivedi S, Singh V, Sharma K, Sliti A, Baunthiyal M, et al. Significance of soy-based fermented food and their bioactive compounds against obesity, diabetes, and cardiovascular diseases. Plant Foods Hum Nutr. 2024;79(1):1–11. https://doi.org/10.1007/s11130-023-01130-1

.“)]. The functional properties and health benefits of fermented foods are summarized in Table 1. Table 1 summarizes the functional properties and health benefits of various traditional Korean fermented foods. Traditional jang and jeotgal consistently exhibit bioactivities such as antioxidant, anti-inflammatory, antihypertensive, and immunomodulatory effects. These findings underscore the health-promoting potential of these foods and highlight the contribution of fermentation-derived bioactive compounds to their functional properties.

Recent metabolomics studies have demonstrated that fermentation-derived metabolites, such as short-chain fatty acids, isoflavone derivatives, and indole compounds, are closely associated with anti-inflammatory, antioxidant, and metabolic regulatory effects. Such evidence highlights the pivotal role of metabolomics in linking specific metabolic profiles to the bioactivity of Korean fermented foods.

Although fermented soybean products like doenjang and ganjang are sodium-rich, both in vitro and in vivo studies have demonstrated that these products exhibit angiotensin-converting enzyme (ACE) inhibitory activity, which may contribute to blood pressure regulation [[28](#ref-CR28 “Mun EG, Park JE, Cha YS. Effects of doenjang, a traditional Korean soybean paste, with high-salt diet on blood pressure in Sprague-Dawley rats. Nutrients. 2019. https://doi.org/10.3390/nu11112745

.“),[29](#ref-CR29 “Mun EG, Sohn HS, Kim MS, Cha YS. Antihypertensive effect of ganjang (traditional Korean soy sauce) on Sprague-Dawley rats. Nutr Res Pract. 2017;11(5):388–95. https://doi.org/10.4162/nrp.2017.11.5.388

.“),[30](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR30 “Woo H, Park JE, Cha YS. Korean traditional fermented soybean paste (doenjang) regulate renin-angiotensin system (RAS) in 3T3-L1 adipocytes. Curr Dev Nutr. 2020. https://doi.org/10.1093/cdn/nzaa052_060

.“)]. Specifically, doenjang has been shown to inhibit ACE activity and reduce lipid accumulation in adipocytes in vitro, suggesting its dual role in blood pressure modulation and anti-obesity effects [[30](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR30 “Woo H, Park JE, Cha YS. Korean traditional fermented soybean paste (doenjang) regulate renin-angiotensin system (RAS) in 3T3-L1 adipocytes. Curr Dev Nutr. 2020. https://doi.org/10.1093/cdn/nzaa052_060

.“)]. Animal models have further supported these findings by showing reductions in serum leptin and improvements in the atherogenic index after consumption of doenjang [[31](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR31 “Edward OC, Jeong DY, Yang HJ, Han A, Cha YS. Doenjang ameliorates diet-induced hyperlipidemia and hepatic oxidative damage by improving lipid metabolism, oxidative stress, and inflammation in ICR mice. 2024. Foods. https://doi.org/10.3390/foods13101471

.“)]. Clinical trials reinforce these outcomes: a 12-week intervention with doenjang in overweight adults resulted in significant reductions in body weight and visceral fat, indicating its efficacy as a functional food for weight management [[32](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR32 “Cha YS, Yang JA, Back HI, Kim SR, Kim MG, et al. Visceral fat and body weight are reduced in overweight adults by the supplementation of doenjang, a fermented soybean paste. Nutr Res Pract. 2012;6(6):520–6. https://doi.org/10.4162/nrp.2012.6.6.520

.“)]. Similarly, gochujang, rich in capsaicin, has demonstrated both antihypertensive and anti-obesity effects in human studies, with participants exhibiting reduced blood pressure, heart rate, and abdominal fat following daily intake [[33](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR33 “Jung SJ, Park SH, Choi EK, Cha YS, Cho BH, et al. Beneficial effects of Korean traditional diets in hypertensive and type 2 diabetic patients. J Med Food. 2014;17(1):161–71. https://doi.org/10.1089/jmf.2013.3042

.“), [34](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR34 “Cha YS, Kim SR, Yang JA, Back HI, Kim MG, et al. Kochujang, fermented soybean-based red pepper paste, decreases visceral fat and improves blood lipid profiles in overweight adults. Nutr Metab. 2013;10(1):24. https://doi.org/10.1186/1743-7075-10-24

.“)]. These findings suggest that gochujang may serve as a dual-functional seasoning with cardiometabolic benefits [[34](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR34 “Cha YS, Kim SR, Yang JA, Back HI, Kim MG, et al. Kochujang, fermented soybean-based red pepper paste, decreases visceral fat and improves blood lipid profiles in overweight adults. Nutr Metab. 2013;10(1):24. https://doi.org/10.1186/1743-7075-10-24

.“), [35](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR35 “Maleki Sedgi F, Mozaffari N, Pashaei MR, Hajizadeh-Sharafabad F. Effect of fermented soybean on metabolic outcomes, anthropometric indices, and body composition: a systematic review and meta-analysis of clinical trials. Food Funct. 2025;16(2):389–405. https://doi.org/10.1039/D4FO02668C

.“)].

The physiological benefits of fermented soy foods are largely attributed to their high concentrations of bioactive compounds, including the aglycone forms of isoflavones, genistein, daidzein, and glycetein. These compounds are known to modulate lipid metabolism, reduce inflammation, and exert antioxidant effects [[36](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR36 “Gupta SK, Dongare S, Mathur R, Mohanty IR, Srivastava S, et al. Genistein ameliorates cardiac inflammation and oxidative stress in streptozotocin-induced diabetic cardiomyopathy in rats. Mol Cell Biochem. 2015;408(1–2):63–72. https://doi.org/10.1007/s11010-015-2483-2

.“)]. Mechanistically, isoflavones have been shown to lower blood cholesterol levels by inhibiting LDL absorption and enhancing bile acid excretion, thereby contributing to cardiovascular protection [[37](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR37 “Islam SU, Ahmed MB, Ahsan H, Lee YS. Recent molecular mechanisms and beneficial effects of phytochemicals and plant-based whole foods in reducing LDL-C and preventing cardiovascular disease. Antioxidants. 2021. https://doi.org/10.3390/antiox10050784

.“)].

Cheonggukjang, a short-term fermented soybean paste, is particularly rich in isoflavones. Especially, in animal models, cheonggukjang consumption has been shown to modulate oxidative stress and inflammatory responses, while in vitro studies suggest it may promote neurostimulatory effects [[38](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR38 “Lee JH, Paek SH, Shin HW, Lee SY, Moon BS, et al. Effect of fermented soybean products intake on the overall immune safety and function in mice. J Vet Sci. 2017;18(1):25–32. https://doi.org/10.4142/jvs.2017.18.1.25

.“), [39](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR39 “Jeong DY, Ryu MS, Yang HJ, Park S. γ-PGA-rich chungkookjang, short-term fermented soybeans: prevents memory impairment by modulating brain insulin sensitivity, neuro-inflammation, and the gut–microbiome–brain axis. Foods. 2021;10(2):221. https://doi.org/10.3390/foods10020221

.“)].

Korean fermented foods have also shown promise in immune function enhancement. For example, cheonggukjang has been reported to stimulate both humoral and cellular immune responses in animal models [[38](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR38 “Lee JH, Paek SH, Shin HW, Lee SY, Moon BS, et al. Effect of fermented soybean products intake on the overall immune safety and function in mice. J Vet Sci. 2017;18(1):25–32. https://doi.org/10.4142/jvs.2017.18.1.25

.“)]. The immunomodulatory effects are linked to its unique composition of bioactive molecules. Likewise, gochujang and ganjang have demonstrated antioxidant and antimutagenic properties in in vitro and in vivo assays [[40](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR40 “Kwon DY, Chung KR, Yang H-J, Jang D-J. Gochujang (Korean red pepper paste): a Korean ethnic sauce, its role and history. J Ethn Foods. 2015;2(1):29–35. https://doi.org/10.1016/j.jef.2015.02.006

.“), [41](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR41 “Lim HJ, Park IS, Kim MJ, Seo JW, Ha G, Yang HJ, et al. Protective effect of ganjang, a traditional fermented soy sauce, on colitis-associated colorectal cancer in mice. 2025. Foods. https://doi.org/10.3390/foods14040632

.“)].

Doenjang has also emerged as a potential anti-cancer and anti-inflammatory agent. Preclinical studies suggest that it can suppress colorectal tumor formation, reduce proinflammatory cytokine expression, and alleviate symptoms associated with neoplasia [[42](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR42 “Jeong JK, Chang HK, Park KY. Doenjang prepared with mixed starter cultures attenuates azoxymethane and dextran sulfate sodium-induced colitis-associated colon carcinogenesis in mice. J Carcinog. 2014;13:9. https://doi.org/10.4103/1477-3163.137699

.“)]. These findings underline the potential of doenjang as a dietary tool for inflammation-related chronic conditions.

Jeotgal, a category of high-salt fermented seafood products, is characterized by extensive protein hydrolysis and the production of diverse peptides and free amino acids. These compounds contribute not only to its umami flavor but also to its functional potential. Recent in vitro studies have identified bioactive peptides from jeotgal with ACE-inhibitory and antioxidant activities, suggesting roles in blood pressure modulation and oxidative stress regulation [43].

Furthermore, metabolomics-based profiling of jeotgal has revealed time-dependent accumulation of functional metabolites, including amino acids and nucleotide derivatives (e.g., ATP, ADP, IMP), which may support gut microbiota balance and overall intestinal health [[1](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR1 “Jung SJ, Chae SW, Shin DH. Fermented foods of Korea and their functionalities. Fermentation. 2022;8(11):645. https://doi.org/10.3390/fermentation8110645

.“)]. Metabolomics-based profiling of jeotgal has revealed time-dependent accumulation of functional compounds, underscoring its potential as a functional food ingredient. To complement findings from in vitro and animal models, several human intervention studies have been conducted to evaluate the health benefits of Korean traditional fermented foods. Although the number of clinical studies remains limited compared to preclinical research, existing evidence supports their roles in weight management, blood pressure regulation, lipid profile improvement, and immune modulation. A summary of representative human trials on doenjang, gochujang, and cheonggukjang is provided in Table 2, highlighting study design, population, intervention duration, and key findings.

Concept of metabolomics and its applications in the study of Korean traditional fermented foods

Fundamental principles and analytical techniques of metabolomics

Metabolites are small biomolecules that participate in enzyme-catalyzed reactions within cells and undergo dynamic changes in their chemical structure, properties, and functions through a series of biochemical pathways. As the end products of gene expression and protein activity, metabolites most directly reflect the phenotype of a biological system. Given that food serves as a fundamental source of nutrition and energy for human life, there is growing interest in detailed analyses of food components and their integrated metabolic processes. Such investigations are increasingly recognized as essential in the fields of nutrition science, functional food development, and disease prevention [[44](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR44 “Hu C, Xu G. Mass-spectrometry-based metabolomics analysis for foodomics. TrAC Trends Anal Chem. 2013;52:36–46. https://doi.org/10.1016/j.trac.2013.09.005

.“)].

Metabolomics methodologies are generally categorized into 2 main types: targeted and untargeted approaches. Targeted metabolomics aims to accurately quantify and characterize a predefined set of metabolites, often relying on established compound libraries for reference [[45](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR45 “Gold ND, Gowen CM, Lussier FX, Cautha SC, Mahadevan R, et al. Metabolic engineering of a tyrosine-overproducing yeast platform using targeted metabolomics. Microb Cell Fact. 2015;14:73. https://doi.org/10.1186/s12934-015-0252-2

.“)]. This method offers high sensitivity and specificity but is limited in scope, as it only examines selected metabolites rather than providing a comprehensive metabolic profile. On the other hand, untargeted metabolomics seeks to capture a holistic view of the metabolic state by detecting as many metabolites as possible without prior selection, allowing the discovery of unexpected or novel biomarkers [[46](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR46 “Zhao H, Liu Y, Li Z, Song Y, Cai X, et al. Identification of essential hypertension biomarkers in human urine by non-targeted metabolomics based on UPLC-Q-TOF/MS. Clin Chim Acta. 2018;486:192–8. https://doi.org/10.1016/j.cca.2018.08.006

.“)]. Nontargeted metabolomics employs high-resolution mass spectrometry platforms such as Time-of-Flight (TOF), Orbitrap, and Fourier Transform Ion Cyclotron Resonance to comprehensively detect and analyze the widest possible range of metabolites [[47](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR47 “Gonzalez-Pena D, Brennan L. Recent advances in the application of metabolomics for nutrition and health. Annu Rev Food Sci Technol. 2019;10:479–519. https://doi.org/10.1146/annurev-food-032818-121715

.“)].

Advantages of metabolomic analysis in traditional fermented foods

Traditional fermented foods generate a wide array of complex metabolites through the intricate interactions of diverse microbial communities and unique fermentation environments. Metabolomics offers a powerful and systematic approach for analyzing these multifaceted metabolic profiles, thereby facilitating the identification of beneficial bioactive compounds produced during fermentation [[48](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR48 “Ray M, Ghosh K, Singh S, Mondal KC. Folk to functional: an explorative overview of rice-based fermented foods and beverages in India. J Ethnic Foods. 2016;3(1):5–18. https://doi.org/10.1016/j.jef.2016.02.002

.“)]. With the rising consumer interest in health maintenance and the prevention of chronic diseases, metabolomic profiling of fermented foods has emerged as a valuable approach. It enables the monitoring of key metabolites produced during fermentation, thereby facilitating the prediction and evaluation of qualitative attributes such as nutritional value, flavor, and safety [[49](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR49 “Ferri M, Serrazanetti DI, Tassoni A, Baldissarri M, Gianotti A. Improving the functional and sensorial profile of cereal-based fermented foods by selecting Lactobacillus plantarum strains via a metabolomics approach. Food Res Int. 2016;89:1095–105. https://doi.org/10.1016/j.foodres.2016.08.044

.“), [50](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR50 “Zhao Y, Wu C, Zhu Y, Zhou C, Xiong Z, et al. Metabolomics strategy for revealing the components in fermented barley extracts with Lactobacillus plantarum dy-1. Food Res Int. 2021;139:109808. https://doi.org/10.1016/j.foodres.2020.109808

.“)]. The flavor of fermented foods is predominantly derived from microbial metabolism and enzymatic biochemical reactions, with the volatile flavor compounds typically identified using gas chromatography–mass spectrometry (GC–MS) [[51](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR51 “Zhang H, Wang L, Tan Y, Wang H, Yang F, et al. Effect of Pichia on shaping the fermentation microbial community of sauce-flavor Baijiu. Int J Food Microbiol. 2021;336:108898. https://doi.org/10.1016/j.ijfoodmicro.2020.108898

.“), [52](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR52 “Zhou Z, Jian D, Gong M, Zhu S, Li G, Zhang S, et al. Characterization of the key aroma compounds in aged Zhenjiang aromatic vinegar by gas chromatography-olfactometry-mass spectrometry, quantitative measurements, aroma recombination and omission experiments. Food Res Int. 2020;136:109434. https://doi.org/10.1016/j.foodres.2020.109434

.“)]. In recent years, as consumer awareness has increased not only regarding the sensory and nutritional qualities of food but also its safety, there has been a growing body of research utilizing metabolomics to characterize and assess the safety attributes of fermented products.

Beyond profiling nutritional composition, sensory characteristics, and safety attributes, metabolomic analysis offers a comprehensive framework for elucidating the biochemical complexity of traditional fermented foods [[53](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR53 “Wang Z, Jin X, Zhang X, Xie X, Tu Z, et al. From function to metabolome: metabolomic analysis reveals the effect of probiotic fermentation on the chemical compositions and biological activities of Perilla frutescens leaves. Front Nutr. 2022;9:933193. https://doi.org/10.3389/fnut.2022.933193

.“), [54](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR54 “Kortesniemi M, Noerman S, Karlund A, Raita J, Meuronen T, et al. Nutritional metabolomics: recent developments and future needs. Curr Opin Chem Biol. 2023;77:102400. https://doi.org/10.1016/j.cbpa.2023.102400

.“)]. This approach is particularly valuable given the dynamic microbial consortia and heterogeneous fermentation environments that define artisanal fermentation processes. When integrated with microbiome data, metabolomics enables the construction of microbial–metabolite association networks, facilitating the identification of key microbial taxa that drive the biosynthesis of functional metabolites and influence fermentation outcomes. Such analyses support the discovery of novel bioactive compounds with potential nutraceutical applications, many of which may be overlooked by targeted analytical methods. Additionally, untargeted metabolomic profiling provides objective criteria for product authentication and quality control, thus aiding the standardization and industrial scalability of traditional fermented foods while preserving their cultural and functional integrity [[55](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR55 “Walsh AM, Leech J, Huttenhower C, Delhomme-Nguyen H, Crispie F, et al. Integrated molecular approaches for fermented food microbiome research. FEMS Microbiol Rev. 2023. https://doi.org/10.1093/femsre/fuad001

.“)].

Trends in metabolomic analysis of traditional foods both domestically and internationally, research outcomes, and industrial application potential.

Doenjang’s quality significantly varies based on factors such as its manufacturing process, fermentation microbiota, fermentation period, and ingredients used, all of which are critical determinants of its characteristics and nutritional value. However, research on metabolomic differences between various types of doenjang remains relatively scarce. Recent untargeted metabolomics studies comparing traditional and commercial doenjang have revealed that traditional doenjang contains relatively higher levels of important nutritional components, such as amino acids and organic acids [[56](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR56 “Soung SH, Lee S, Lee SH, Kim HJ, Lee NR, Lee CH. Metabolomic-based comparison of traditional and industrial doenjang samples with antioxidative activities. 2021. Foods. https://doi.org/10.3390/foods10061377

.“)]. A notable accumulation of amino acids, including alanine, valine, leucine, isoleucine, proline, glutamine, phenylalanine, and lysine, was observed, particularly during the later phases of the fermentation process. Among the identified organic acids, carbonic acid, citric acid, lactic acid, and pyroglutamic acid were predominant. Additionally, substantial concentrations of erythrose, xylitol, inositol, and mannitol emerged throughout fermentation. In terms of fatty acid composition, doenjang consistently contained relatively high levels of palmitic acid, stearic acid, oleic acid, linoleic acid, and linolenic acid at various fermentation stages [[57](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR57 “Namgung HJ, Park HJ, Cho IH, Choi HK, Kwon DY, et al. Metabolite profiling of doenjang, fermented soybean paste, during fermentation. J Sci Food Agric. 2010;90(11):1926–35. https://doi.org/10.1002/jsfa.4036

.“)]. This discovery reflects the beneficial metabolites generated by differences in the fermentation process and microbial communities, providing scientific support for the nutritional excellence of traditional manufacturing methods.

Comparative metabolomic studies in fermented soy-based foods like Japanese miso and Chinese doubanjiang have also revealed similar trends in amino acid and isoflavone enrichment [[58](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR58 “Niu C, Xing X, Zheng F, Liu C, Wang J, et al. Effect of salt reduction on nutritional, functional and sensory aspects of Anhui-style doubanjiang, a traditional Chinese broad bean paste. Syst Microbiol Biomanuf. 2023;3(2):262–72. https://doi.org/10.1007/s43393-022-00112-9

.“)]. In Japan, miso, a traditional fermented soybean paste, has been the subject of several metabolomics-based studies aimed at elucidating its nutritional and functional composition. Due to its complex fermentation involving Aspergillus oryzae, lactic acid bacteria, and yeast, miso produces a wide range of bioactive metabolites including amino acids, peptides, isoflavones, and organic acids. Recent untargeted metabolomics approaches using techniques such as GC–MS and liquid chromatography–mass spectrometry (LC–MS) have revealed significant variations in the metabolite profiles of different types of miso (e.g., white miso, red miso, and mixed miso), depending on fermentation duration, microbial consortium, and ingredient composition [[59](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR59 “Kwon YS, Lee S, Lee SH, Kim HJ, Lee CH. Comparative evaluation of six traditional fermented soybean products in East Asia: a metabolomics approach. Metabolites. 2019. https://doi.org/10.3390/metabo9090183

.“)].

Long-term fermented traditional miso showed higher concentrations of glutamic acid, GABA, and specific antioxidant peptides than commercially produced miso, enhancing umami flavor and conferring potential neuroprotective and antihypertensive benefits [[60](https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-025-00294-2#ref-CR60 “Allwood JG, Wakeling LT, Bean DC. Fermentation and the microbial community of Japanese koji and miso: a review. J Food Sci. 2021;86(6):2194–207. https://doi.org/10.1111/1750-3841.15773

.“)]. Certain metabolites have also been proposed as markers for monitoring fermentation progress and product quality.

Incorporating multi-omics approaches, metagenomics, metatranscriptomics, and metabolomics, has provided a systems-level understanding of fermentation dynamics. Metagenomics identifies the potential functional genes within microbial communities, metatranscriptomics elucidates active metabolic pathways, and metabolomics quantifies the biochemical output, including amino acids, peptides, organic acids, and other bioactive compounds. Representative studie