Traditional Korean Food Research Articles

Biochemical and Thermodynamic Characterization of a Novel, Low Molecular Weight Xylanase from Bacillus Methylotrophicus CSB40 Isolated from Traditional Korean Food.

A low molecular weight xylanase from Bacillus strain CSB40, isolated from traditional Korean food and produced in beechwood xylan, was biochemically and thermodynamically characterized. It was purified 8.12-fold with a 15.88% yield using DEAE sepharose fast flow, and it was determined to have a mass of ∼27kDa via sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and xylan zymography. The purified xylanase was optimally active at 50°C and pH 6 and stable over a wide range of pH (4.5-12.5). The N-terminal amino acid sequence of xylanase was GIQQGDDGKL. The activation energy for beechwood xylan hydrolysis was 29.39kJmol(-1) with k cat value of 927.582 × 10(2)s(-1). K m and V max were 0.080mg/ml and 794.63mmolmin(-1)mg(-1). The analysis of other thermodynamic parameters like ∆H, ∆G, ∆S, Q10, ∆GE-S, and ∆GE-T also supported the spontaneous formation of products, greater hydrolytic efficiency, and feasibility of enzymatic reaction, which also ratifies the novelty of this xylanase. The enzyme was strongly activated by Zn(2+) and inhibited by Cu(2+). The principal hydrolyzed end-products of this xylanase are xylobiose, xylotriose, and xylotetrose, which can be used in the pharmaceutical industry and as prebiotic in food.

Metabolic Pathways Associated with Kimchi, a Traditional Korean Food, Based on In Silico Modeling of Published Data.

Kimchi is a traditional Korean food prepared by fermenting vegetables, such as Chinese cabbage and radishes, which are seasoned with various ingredients, including red pepper powder, garlic, ginger, green onion, fermented seafood (Jeotgal), and salt. The various unique microorganisms and bioactive components in kimchi show antioxidant activity and have been associated with an enhanced immune response, as well as anti-cancer and anti-diabetic effects. Red pepper inhibits decay due to microorganisms and prevents food from spoiling. The vast amount of biological information generated by academic and industrial research groups is reflected in a rapidly growing body of scientific literature and expanding data resources. However, the genome, biological pathway, and related disease data are insufficient to explain the health benefits of kimchi because of the varied and heterogeneous data types. Therefore, we have constructed an appropriate semantic data model based on an integrated food knowledge database and analyzed the functional and biological processes associated with kimchi in silico. This complex semantic network of several entities and connections was generalized to answer complex questions, and we demonstrated how specific disease pathways are related to kimchi consumption.

Characterization of antimicrobial lipopeptides produced by Bacillus sp. LM7 isolated from chungkookjang, a Korean traditional fermented soybean food

A wild-type microorganism exhibiting antimicrobial activities was isolated from the Korean traditional fermented soybean food Chungkookjang and identified as Bacillus sp. LM7. During its stationary growth phase, the microorganism secreted an antimicrobial substance, which we partially purified using a simple two-step procedure involving ammonium sulfate precipitation and heat treatment. The partially purified antimicrobial substance, Anti-LM7, was stable over a broad pH range (4.0–9.0) and at temperatures up to 80°C for 30min, and was resistant to most proteolytic enzymes and maintained its activity in 30% (v/v) organic solvents. Anti-LM7 inhibited the growth of a broad range of Gram-positive bacteria, including Bacillus cereus and Listeria monocytogenes, but it did not inhibit lactic acid bacteria such as Lactobacillus plantarum and Lactococcus lactis subsp. Lactis. Moreover, unlike commercially available nisin and polymyxin B, Anti-LM7 inhibited certain fungal strains. Lastly, liquid chromatography-mass spectrometry analysis of Anti-LM7 revealed that it contained eight lipopeptides belonging to two families: four bacillomycin D and four surfactin analogs. These Bacillus sp. LM7-produced heterogeneous lipopeptides exhibiting extremely high stability and a broad antimicrobial spectrum are likely to be closely related to the antimicrobial activity of Chungkookjang, and their identification presents an opportunity for application of the peptides in environmental bioremediation, pharmaceutical, cosmetic, and food industries.

Origin names of gochu, kimchi, and bibimbap

BackgroundDespite the long history of Korean foods, the truth and history behind them are either scaled down or distorted due to several scholars who happen to “know” hanja (漢字). A representative case is the distortion of the history of gochu, which inflicts serious distortion on foods that also use the very ingredient. As the distorted history of gochu is pushed forward to be true, the history and the origin name words for gochu, gochujang, and bibimbap are perverted as a result. Hence, food research will proceed in the right direction when such misrepresented origin names are corrected. MethodsThis paper aims to correct the existing inaccurate theories by following the principal that the existence of objects come before their written records, analyzing the actual old records of gochu, kimchi, and bibimbap, and integrating them with the development process of Korean verbal and written language. In addition, reasons as to why scholars resorted to such distorted claims will be explained. ResultsIt is entirely wrong to take hanja names as the origin names for Korean traditional foods simply based on the hanja records of these foods or agricultural products. The hanja records only mean that the Korean people simply borrowed hanja to write the names of the foods they made and enjoyed for a long time. This being said, the claims that the origins names for gochu, kimchi, and bibimbap are gocho (苦椒), chimchae (沈菜), and koldonban (滑董飯) are false. In fact, the correct ones are gochyo (고쵸), dimchae (딤▪), and bubuimbap (부뷤밥). The reason why scholars kept on arguing that the hanja names are the origin names lies in their attempt to distort the history of gochu, kimchi, and bibimbap in order to rationalize their claims that gochu were introduced during Imjinwareran War—the Japanese Invasion of Korea in 1592. ConclusionGochu, kimchi, and bibimbap have thousands of years of history and have been called with pure Korean name words. It was only that they were recorded in the form of hanja during the time written Korean was undervalued where people insisted borrowing Chinese characters to write despite written Korean being available. Thus, gocho (苦椒), chimchae (沈菜), and koldonban (滑董飯) are not the origin names. The pure Korean names used even by the people back then are the actual ones: gochyo (고쵸), dimchae (딤▪), and bubuimbap (부뷤밥).

Development of a Pasting and Garnishing Machine for Manufacturing Kimbugak

, 2015Purpose: Kimbugak is one of Korea’s traditional snack foods made of laver. Mechanization of the manufacturing process is necessary to produce kimbugak in large quantities and standardize the products for industrialization. This study was conducted to develop a machine that can simultaneously accomplish the two processes of pasting and garnishing for manufacturing kimbugak, and test its performance. Methods: A pasting and garnishing machine was designed, and its target work efficiency was set at 720 sheets/h. The performance was tested based on the physical characteristics such as work efficiency, pasting uniformity, and garnishing uniformity. Results: With the developed technology, kimbugak could be produced up to a productive rate of 840 sheets/h on a single machine. The pasting uniformity ranged from 91.5% to 96.8%, and a garnishing uniformity of more than 90% could be obtained. Conclusions: It is expected that this approach to developing a machine with the functions of pasting and garnishing can contribute to the mechanization of the manufacturing process to produce Korean traditional foods including kimbugak in large quantities and standardize the products for industrialization.Keywords: Garnishing, Kimbugak, Laver, Manufacturing machine, Pasting

한국전통식품으로부터 분리 된 세균의 항균활성 효과

한국전통식품으로부터 분리 된 세균의 항균활성 효과

The evaluation of metabolizable energy in traditional Korean food for protein sources

BackgroundThe validity of energy data in the composition table of Korean food has been in question due to possible differences in its chemical composition from that of western food. Traditional Korean food involves a diverse range of food ingredients so there has been considerable doubt regarding the accuracy of the energy level derived from chemical analysis and energy conversion factors. MethodsThis study was undertaken to determine the metabolizable energy of Korean food by animal testing. Cooked foods (12 items) were freeze-dried and fed to Sprague–Dawley rats with body weight 200–300 g to measure apparent metabolizable energy values for 4 days after 3 days of preliminary adaptation to the diets. ResultsWhen the apparent metabolizable energy values of Korean foods measured in this study were compared with energy values calculated by various conversion parameters such as those of Atwater, Rubner, Sochun, and the Food and Agriculture Organization, there were big differences indicating that the energy values calculated using the other conversion factors are hardly acceptable for many food items. ConclusionThe various food ingredients involved in the cooking process of traditional Korean food lead to differences between the energy level attained from chemical analysis and from actual animal testing.

Bacillus licheniformis Isolated from Traditional Korean Food Resources Enhances the Longevity of Caenorhabditis elegans through Serotonin Signaling.

In this study, we investigated potentially probiotic Bacillus licheniformis strains isolated from traditional Korean food sources for ability to enhance longevity using the nematode Caenorhabditis elegans as a simple in vivo animal model. We first investigated whether B. licheniformis strains were capable of modulating the lifespan of C. elegans. Among the tested strains, preconditioning with four B. licheniformis strains significantly enhanced the longevity of C. elegans. Unexpectedly, plate counting and transmission electron microscopy (TEM) results indicated that B. licheniformis strains were not more highly attached to the C. elegans intestine compared with Escherichia coli OP50 or Lactobacillus rhamnosus GG controls. In addition, qRT-PCR and an aging assay with mutant worms showed that the conditioning of B. licheniformis strain 141 directly influenced genes associated with serotonin signaling in nematodes, including tph-1 (tryptophan hydroxylase), bas-1 (serotonin- and dopamine-synthetic aromatic amino acid decarboxylase), mod-1 (serotonin-gated chloride channel), ser-1, and ser-7 (serotonin receptors) during C. elegans aging. Our findings suggest that B. licheniformis strain 141, which is isolated from traditional Korean foods, is a probiotic generally recognized as safe (GRAS) strain that enhances the lifespan of C. elegans via host serotonin signaling.

Immunomodulatory effects of Leuconostoc citreum EFEL2061 isolated from kimchi, a traditional Korean food, on the Th2 type-dominant immune response in vitro and in vivo

We isolated several novel Leuconostoc citreum (LC) strains from kimchi, a traditional Korean fermented food, and screened for potential probiotics that have immunomodulatory activity toward the hyperactive Th2 response. After screening, we chose the LC EFEL2061 strain for its ability to induce strong interleukin (IL)-12 expression in mouse macrophages. This strain enhanced interferon (IFN)-γ production by mouse splenocytes cultured under Th2 polarisation conditions. Oral administration of LC EFEL2061 to ovalbumin (OVA)-sensitised mice significantly reduced the serum level of total IgE, but not that of OVA-specific IgE. Spleens from the LC EFEL2061 group had fewer CD19(+)CD80(+) cells than the OVA group and more CD40(+)CD86(+) cells than the sham group. Thus, LC EFEL2061 strongly induced Th1 type cytokines in vitro and, when consumed, decreased the elevated total IgE in serum in OVA-sensitised mice, possibly by downregulating bystander B cell activation or by upregulating the activity of innate immune cells.

Fucoxanthin Inhibits the Inflammation Response in Paw Edema Model through Suppressing MAPKs, Akt, and NFκB.

Undaria pinnatifida is a well-known traditional Korean food with a variety of biological activities. Carrageenan (carr) is commonly used to induce paw edema in animal models. This study was designed to elucidate the processes underlying the anti-inflammatory effect of fucoxanthin isolated from the sporophyll of U. pinnatifida in carr-induced paw edema in ICR mice. Fucoxanthin significantly decreased carr-induced increased nitric oxide levels in the plasma of mice with carr-induced paw edema. Fucoxanthin protected catalase (CAT) and superoxide dismutase (SOD) activity against disruption in mice with carr-induced paw edema. In addition, fucoxanthin repressed carr-induced activation of inducible nitric oxide synthase, cyclooxygenase-2, and nuclear factor kappa B, as well as carr-induced phosphorylation of mitogen-activated protein kinase, extracellular signal-regulated kinase, c-Jun N-terminal kinase, p38, and protein kinase B/Akt. These results suggest that fucoxanthin may have therapeutic potential as a treatment for patients with inflammatory diseases.

Conversion of Flavonols Kaempferol and Quercetin in Mulberry (M orus Alba L.) Leaf Using Plant-Fermenting L actobacillus Plantarum

The aim of this study was to examine the levels of flavonols in mulberry leaf fermented by Lactobacillus plantarum isolated from a traditional Korean soybean-fermented food. Flavonol kaempferol and quercetin contents were markedly higher in fermentates of mulberry leave (FML) extracts than in unfermented mulberry leave (UFML) extracts (kaempferol and quercetin: 30.43 ± 1.83 mg/100 g and 49.96 ± 2.74 mg/100 g equivalent weight of dry in FML versus 0.54 ± 0.11 mg/100 g and 0.58 ± 0.15 mg/100 g equivalent weight of dry in UFML). In addition, total phenolic and flavonoid contents in FML extract were 1,183.28 ± 2.99 mg/100 g equivalent weight of dry and 425.61 ± 9.73 mg/100 g equivalent weight of dry, respectively, which were considerably higher than those of the control UFML extract. Practical Applications Flavonols kaempferol and quercetin with antioxidant and anti-inflammatory properties have been implicated in the prevention and development of therapies for cancers, cardiovascular disease, neurological and metabolic disorders, and bone diseases and so on. These results suggest that Lactobacillus plantarum isolated from a traditional Korean soybean-fermented food could be used as a starter strain for improvement of biologically beneficial flavonol compounds in plant-derived food materials.

Genome sequence of the haloarchaeon Haloterrigena jeotgali type strain A29(T) isolated from salt-fermented food.

Haloterrigena jeotgali is a halophilic archaeon within the family Natrialbaceae that was isolated from shrimp jeotgal, a traditional Korean salt-fermented food. A29T is the type strain of H. jeotgali, and is a Gram-negative staining, non-motile, rod-shaped archaeon that grows in 10 %–30 % (w/v) NaCl. We present the annotated H. jeotgali A29T genome sequence along with a summary of its features. The 4,131,621 bp genome with a GC content of 64.9 % comprises 4,215 protein-coding genes and 127 RNA genes. The sequence can provide useful information on genetic mechanisms that enable haloarchaea to endure a hypersaline environment.

Isolation, expression, and characterization of S-adenosyl-l-methionine synthetase from Lactobacillus paraplantarum 72815

The S-adenosyl-l-methionine (SAM) synthetase gene was mined from Lactobacillus paraplantarum 72815 isolated from the traditional Korean fermented food Kimchi. The gene was cloned and expressed in Escherichia coli to obtain recombinant SAM synthetase (SAM-s-LP). The purified SAM-s-LP was characterized as 40°C and pH 8.5 as the optimal temperature and pH for activity, respectively. The apparent K m values of SAM-s-LP were 1.47±0.59 mM for l-Met and 2.84±0.82 mM for ATP.

Probiotic potential of nutritionally improved Lactobacillus plantarum DGK-17 isolated from Kimchi – A traditional Korean fermented food

The aim of the study was to evaluate the functional properties of the Lactic acid bacterium Lactobacillus plantarum DGK-17 isolated from Kimchi-a traditional fermented Korean food, and to assess its antimicrobial and cell-invasion protection activity. Nutritionally improved DGK-17 showed antimicrobial activity, checked via agar well diffusion assay against several pathogenic microorganisms and showed enhanced antimicrobial activity against target microbes Pseudomonas aeruginosa 03K711 and Klebsiella pneumoniae 05K279. Bactericidal activity of DGK-17 Cell-free Culture Supernatant (CFCS) was evident from the decreased growth of P. aeruginosa 03K711 and K. pneumoniae 05K279. Altered membrane integrity was observed in scanning electron microscopy which indicated that CFCS acts on cell membrane of bacteria leading to a cell burst. CFCS also acts on DNA as shown by the DNA damage study. Our auto-aggregation, co-aggregation and adhesion studies indicated that DGK-17 prevents colonization of pathogenic bacteria thereby limiting their infection. Also, DGK-17 is able to survive under low pH and high bile salt conditions – a simulated gastric juice environment. Efficacy of DGK-17 to protect HCT 116 colon cells against P. aeruginosa (03K711) and K. pneumoniae (05K279) invasion suggests its role in protection of host cells from such infections. Finally we conclude that L. plantarum DGK-17 has a strong probiotic potential, antimicrobial activity and a potential for invasion protection.

Study on Recognition, Acceptance, and Satisfaction of Dessert Menus on Elementary School Food Services in Seoul Province

The purpose of this study was to evaluate perception, acceptance and satisfaction of dessert menu in elementary school children. Five hundred students (246 male, 254 female) were recruited at the elementary schools in Seoul. The results show that dessert menus of elementary school lunches are needed to satisfy diverse acceptance and preference levels of children. For dessert items chocolate milk among beverage items, peaches among fruits, chocolate cookies among cookies, piece cake among breads and honey rice cake among rice cakes presented high acceptance scores. Furthermore, fruits, ice creams, juices and cookies were the most liked food items. Taste and health of desserts were important factors in perception of dessert. Rice cake (48.6%), a Korean traditional food, was the most preferred food item, followed by tea punch (31.2%), Korean cracker (10.0%) and Shanja (4.0%). Taste (51.4%) was considered as the most important factor for improvement of dessert, and increasing variety of dessert items (43.4%) was considered as the most important factor affecting demand of dessert. It is suggested that continuous update of school dessert menus is needed to meet consumers’ demands and health aspects. Furthermore, Korean traditional desserts might be the key for improving satisfaction in desserts in elementary school lunches.

Sensory characteristics and cross-cultural acceptability of Chinese and Korean consumers for ready-to-heat (RTH) type bulgogi (Korean traditional barbecued beef)

Bulgogi (Korean-traditional barbequed beef) is one of the most popular Korean traditional foods. China, the world’s most populous country, is a huge market that has the biggest market potential in the world. The purpose of the study was to understand the preference of Chinese consumers for bulgogi products in comparison to that of Korean consumers. Sensory characteristics of bulgogi samples that differed in levels of main marinating ingredients were examined using descriptive analysis and results were connected to hedonic information collected from Chinese (n=72) and Korean (n=76) participants. Bulgogi samples were prepared in ready-to-heat form. Chinese consumers’ overall acceptability was negatively affected by sweet taste, and green onion, black pepper, cooked onion, and sesame flavors. Chinese consumers tended to report that tested bulgogi samples were ‘too sweet’, while Korean consumers thought that sweetness levels were ‘just-right’. The results implied the influence of cultural expectation playing a role in consumer acceptability.

Effect of Chongkukjang on histamine-induced skin wheal response: A randomized, double-blind, placebo-controlled trial

BackgroundStudies in animals have demonstrated the antiallergenic properties of Chongkukjang (CKJ), a traditional Korean food made by fermentation of soybean with Bacillus subtilis. CKJ might therefore be used as an ingredient in a functional food designed to suppress allergies. The purpose of this study was to investigate the effect of CKJ on histamine-induced skin wheal response in healthy participants. MethodsA randomized, double-blind, placebo-controlled trial was conducted. Sixty participants (48 women and 12 men) were randomly assigned to one of two groups: One group received 35 g CKJ daily for 12 weeks, and the other received a placebo at the same dosing frequency. A skin prick test with histamine (10 mg/mL) was conducted on the ventral forearm 10 cm from the elbow, and assessed 15 minutes later. Outcomes included measurement of efficacy [skin wheal response, immunoglobulin E (IgE), histamine, interferon-gamma, interleukin-4, eosinophil, and eosinophil cationic protein (ECP)], and safety (adverse events, laboratory test results, electrocardiogram, anthropometric values, and vital signs). ResultsFifty-five participants (28 in the CKJ group and 27 in the placebo group) completed the study. After 12 weeks of supplementation, participants in the CKJ group showed a significant reduction in histamine-induced skin wheal areas compared with placebo group (p < 0.05). At 12 weeks, the CKJ group showed a significant improvement in percentage change from baseline in histamine-induced wheal area, compared with the placebo group (p < 0.05). CKJ did not influence blood levels of IgE, histamine, interferon-gamma, interleukin-4, eosinophil, or ECP. ConclusionOral administration of CKJ for 12 weeks resulted in a reduction of the skin wheal response to histamine, with no apparent adverse effects. Trial registration: ClinicalTrials.gov: NCT01402141.

Production of Functional High-protein Beverage Fermented with Lactic Acid Bacteria Isolated from Korean Traditional Fermented Food.

The aim of this study was to manufacture functional high protein fermented beverage, using whey protein concentrate (WPC) and Lactobacillus plantarum DK211 isolated from kimchi, and to evaluate the physicochemical, functional, and sensory properties of the resulting product. The fermented whey beverage (FWB) was formulated with whey protein concentrate 80 (WPC 80), skim milk powder, and sucrose; and fermented with Lactobacillus plantarum DK211 as single, or mixed with Lactococcus lactis R704, a commercial starter culture. The pH, titratable acidity, and viable cell counts during fermentation and storage were evaluated. It was found that the mixed culture showed faster acid development than the single culture. The resulting FWB had high protein (9%) and low fat content (0.2%). Increased viscosity, and antioxidant and antimicrobial activity were observed after fermentation. A viable cell count of 109 CFU/mL in FWB was achieved within 10 h fermentation, and it remained throughout storage at 15℃ for 28 d. Sensory analysis was also conducted, and compared to that of a commercial protein drink. The sensory scores of FWB were similar to those of the commercial protein drink in most attributes, except sourness. The sourness was highly related with the high lactic acid content produced during fermentation. The results showed that WPC and vegetable origin lactic acid bacteria isolated from kimchi might be used for the development of a high protein fermented beverage, with improved functionality and organoleptic properties.

Protective Effects of a Novel Probiotic Strain of Lactobacillus plantarum JSA22 from Traditional Fermented Soybean Food Against Infection by Salmonella enterica Serovar Typhimurium.

Lactobacillus species have been shown to enhance intestinal epithelial barrier function, modulate host immune responses, and suppress the growth of pathogenic bacteria, yeasts, molds, and viruses. Thus, lactobacilli have been used as probiotics for treating various diseases, including intestinal disorders, and as biological preservatives in the food and agricultural industries. However, the molecular mechanisms used by lactobacilli to suppress pathogenic bacterial infections have been poorly characterized. We previously isolated Lactobacillus plantarum JSA22 from buckwheat sokseongjang, a traditional Korean fermented soybean food, which possessed high enzymatic, fibrinolytic, and broad-spectrum antimicrobial activity against foodborne pathogens. In this study, we investigated the effects of L. plantarum JSA22 on the growth of S. Typhimurium and S. Typhimurium-induced cytotoxicity by stimulating the host immune response in intestinal epithelial cells. The results showed that coincubation of S. Typhimurium and L. plantarum JSA22 with intestinal epithelial cells suppressed S. Typhimurium infection, S. Typhimurium-induced NF-kappaB activation, and IL-8 production, and lowered the phosphorylation of both Akt and p38. These data indicated that L. plantarum JSA22 has probiotic properties, and can inhibit S. Typhimurium infection of intestinal epithelial cells. Our findings can be used to develop therapeutic and prophylactic agents against pathogenic bacteria.

Bacillus licheniformis Isolated from Korean Traditional Food Resources Enhances the Lifespan of Caenorhabditis elegans through Serotonin Signaling

Here, we examined potentially probiotic Bacillus spp. with antimicrobial activities from Korean traditional food sources, and evaluated their enhanced longevity using the nematode Caenorhabditis elegans as a simple in vivo animal model. Initially, we selected twenty probiotic Bacillus spp. that produced antimicrobial bacteriocins against various foodborne pathogens. Unexpectedly, plate counting and transmission electron microscopy (TEM) results indicated that the Bacillus spp. strains were not persistent on the C. elegans intestine compared with E. coli OP50 or Lactobacillus rhamnosus GG controls. Next, we determine whether selected Bacillus spp. is capable for modulating the lifespan of C. elegans. Among the tested strains, the pre-conditioning by four Bacillus spp. significantly enhanced the longevity of C. elegans. In addition, qRT-PCR and aging assay with transgenic mutant worms showed that the conditioning of selected Bacillus spp. directly influence on the genes associated with serotonin signaling of nematode including tph-1 (tryptophan hydroxylase), bas-1 (serotonin- and dopamine-synthetic aromatic amino acid decarboxylase), mod-1 (serotonin-gated chloride channel), and ser-1 (serotonin receptors) during aging of C. elegans. Based on 16S rRNA sequencing, the selected strain was identified as B. licheniformis. Our findings propose that probiotic Bacillus spp. isolated from Korean traditional foods may enhance the lifespan of C. elegans via serotonin signaling in host.