World Institute of Kimchi

Gwangju, South Korea

World Institute of Kimchi

Gwangju, South Korea
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Choi E.J.,World Institute of Kimchi | Park H.W.,World Institute of Kimchi | Yang H.S.,World Institute of Kimchi | Chun H.H.,World Institute of Kimchi
LWT - Food Science and Technology | Year: 2017

Dongchimi is a watery variety of kimchi prepared using firm radish and condiments. Over-ripening is the most undesirable outcome of dongchimi fermentation, resulting in softening of texture and an undesirable taste. Herein, the effects of combined treatment with ultraviolet-C (UV-C) irradiation and grape seed extract (GSE) supplementation, followed by supercooled storage, on the quality of dongchimi were investigated. Microbial inactivation tests showed that 6 kJ/m2 UV-C irradiation and 0.1% GSE supplementation before storage significantly reduced the populations of total aerobic bacteria, fungi, and lactic acid bacteria in dongchimi. Supercooled storage (−3 °C) delayed microbial growth in dongchimi compared to refrigeration (4 °C and 10 °C). Supercooled storage also suppressed changes in pH and titratable acidity in dongchimi. The hardness and colour of the radish slices did not vary with the treatments. Sensory evaluation results indicated that the qualities of dongchimi treated with the combination of UV-C and GSE followed by storage at −3 °C were better than those with other treatments. Thus, UV-C irradiation and GSE supplementation improved the final quality and extended dongchimi shelf life under supercooled storage at −3 °C without ice crystal nucleation and formation. © 2017 Elsevier Ltd

Lee M.,World Institute of Kimchi | Song J.H.,World Institute of Kimchi | Jung M.Y.,World Institute of Kimchi | Lee S.H.,World Institute of Kimchi | Chang J.Y.,World Institute of Kimchi
Food Microbiology | Year: 2017

The microbial communities in kimchi vary widely, but the precise effects of differences in region of origin, ingredients, and preparation method on the microbiota are unclear. We analyzed the bacterial community composition of household (n = 69) and commercial (n = 19) kimchi samples obtained from six Korean provinces between April and August 2015. Samples were analyzed by barcoded pyrosequencing targeting the V1–V3 region of the 16S ribosomal RNA gene. The initial pH of the kimchi samples was 5.00–6.39, and the salt concentration was 1.72–4.42%. Except for sampling locality, all categorical variables, i.e., salt concentration, major ingredient, fermentation period, sampling time, and manufacturing process, influenced the bacterial community composition. Particularly, samples were highly clustered by sampling time and salt concentration in non-metric multidimensional scaling plots and an analysis of similarity. These results indicated that the microbial community differed according to fermentation conditions such as salt concentration, major ingredient, fermentation period, and sampling time. Furthermore, fermentation properties, including pH, acidity, salt concentration, and microbial abundance differed between kimchi samples from household and commercial sources. Analyses of changes in bacterial ecology during fermentation will improve our understanding of the biological properties of kimchi, as well as the relationships between these properties and the microbiota of kimchi. © 2017 Elsevier Ltd

Kim D.-I.,Chonnam National University | Park M.J.,Chonnam National University | Lim S.K.,World Institute of Kimchi | Park J.-I.,Korea Basic Science Institute | And 6 more authors.
Diabetes | Year: 2015

Arginine methylation is responsible for diverse biological functions and is mediated by protein arginine methyltransferases (PRMTs). Nonalcoholic fatty liver disease (NAFLD) is accompanied by excessive hepatic lipogenesis via liver X receptor α (LXRα). Thus we examined the pathophysiological role of PRMTs in NAFLD and their relationship with LXRα. In this study, palmitic acid (PA) treatment increased PRMT3, which is correlated with the elevation of hepatic lipogenic proteins. The expression of lipogenic proteins was increased by PRMT3 overexpression, but decreased by PRMT3 silencing and use of the PRMT3 knockout (KO) mouse embryonic fibroblast cell line. PRMT3 also increased the transcriptional activity of LXRα by directly binding with LXRα in a methylation-independent manner. In addition, PA treatment translocated PRMT3 to the nucleus. In animal models, a high-fat diet increased the LXRα and PRMT3 expressions and binding, which was not observed in LXRα KO mice. Furthermore, increased PRMT3 expression and its binding with LXRα were observed in NAFLD patients. Taken together, LXRα and PRMT3 expression was increased in cellular and mouse models of NAFLD and human patients, and PRMT3 translocated into the nucleus bound with LXRα as a transcriptional cofactor, which induced lipogenesis. In conclusion, PRMT3 translocation by PA is coupled to the binding of LXRα, which is responsible for the onset of fatty liver. © 2015 by the American Diabetes Association.

Kim D.-I.,Chonnam National University | Park M.-J.,Chonnam National University | Choi J.-H.,Chonnam National University | Lim S.-K.,World Institute of Kimchi | And 2 more authors.
International Journal of Biochemistry and Cell Biology | Year: 2015

Glucagon-like peptide-1 receptor (GLP-1R) is closely associated with the onset of diabetes and its complications. However, its roles in diabetic retinopathy are unknown. Retinal pigment epithelial (RPE) cells are a crucial component of the outer blood-retina barrier and their death is related to the progression of diabetic retinopathy. Thus, we examined the pathophysiological role of GLP-1R in RPE cell apoptosis. We found that GLP-1R expression was lower in the isolated neuroretina and RPE cells of streptozotocintreated rats than in vehicle-treated rats. High-glucose treatment also decreased GLP-1R expression in a human RPE cell line (ARPE-19 cells). GLP-1R was silenced in ARPE-19 cells, in order to elucidate the pathophysiological roles of GLP-1R. This increased intracellular reactive oxygen species (ROS) generation and activated p53-mediated Bax promoter and endoplasmic reticulum (ER) stress signaling. We also found that GLP-1R knockdown-mediated p53 expression was regulated by ER stress. Interestingly, antioxidant treatment and peroxiredoxin 1 (Prx1) overexpression attenuated GLP-1R knockdown-induced ER stress signaling and p53 expression. Finally, to confirm that GLP-1R activation has protective effects, ARPE-19 cells were treated with exendin-4, a synthetic GLP-1R agonist. This attenuated high-glucose-induced ROS generation, ER stress signaling, and p53 expression. Collectively, these results indicated that hyperglycemia decreases GLP-1R expression in RPE cells. Such a decrease generates intracellular ROS, which increases ER stress-mediated p53 expression, and subsequently causes apoptosis by increasing Bax promoter activity. Our data suggested that regulation of GLP-1R expression is a promising approach for the treatment of diabetic retinopathy. © 2014 Elsevier Ltd. All rights reserved.

Jo E.-J.,Gwangju Institute of Science and Technology | Mun H.,Gwangju Institute of Science and Technology | Kim S.-J.,World Institute of Kimchi | Shim W.-B.,Gyeongsang National University | Kim M.-G.,Gwangju Institute of Science and Technology
Food Chemistry | Year: 2016

We report a chemiluminescence resonance energy transfer (CRET) aptasensor for the detection of ochratoxin A (OTA) in roasted coffee beans. The aptamer sequences used in this study are 5′-DNAzyme-Linker-OTA aptamer-3′-dabcyl. Dabcyl at the end of the OTA aptamer region plays as a quencher in CRET aptasensor. When hemin and OTA are added, the dabcyl-labeled OTA aptamer approaches to the G-quadruplex-hemin complex by formation of the G-quadruplex-OTA complex. The G-quadruplex-hemin complexes possess horseradish peroxidase (HRP)-like activity, and therefore, the HRP-mimicking DNAzyme (HRPzyme) catalyzes peroxidation in the presence of luminol and H2O2. Resonance energy transfer between luminol (donor) and dabcyl (acceptor) enables quenching of chemiluminescence signals. The signal decreases with increasing the concentration of OTA within the range of 0.1-100 ng mL-1 (limit of detection 0.22 ng mL-1), and the level of recovery of the respective 1 ng mL-1 and 10 ng mL-1 spiked coffee samples was 71.5% and 93.3%. These results demonstrated the potential of the proposed method for OTA analysis in diverse foods. © 2015 Elsevier Ltd. All rights reserved.

Park E.-J.,Kyung Hee University | Park E.-J.,Jeju National University | Chun J.,Seoul National University | Cha C.-J.,Chung - Ang University | And 3 more authors.
Food Microbiology | Year: 2012

Kimchi, a food made of fermented vegetables, is densely populated by indigenous microorganisms that originate from the raw ingredients under normal conditions. Most microbiological studies on kimchi have been on the most popular dish, baechu-kimchi (Chinese cabbage kimchi). Therefore, relatively little is known about the various other kinds of kimchi (depending on the region, season, main ingredient, starter culture inoculation and recipe). In this study, we collected 100 samples periodically during the fermentation of ten representative kinds of kimchi (including starter-inoculated kimchi) that were stored in the refrigerator (4°C) during the 30-35 days fermentation period. The multiplex barcoded pyrosequencing of a hypervariable V1-V3 region of the 16S ribosomal RNA (rRNA) gene tagged with sample-specific barcodes for multiplex identifiers was employed for bacterial community profiling. We found that bacterial communities differed between starter-inoculated and non-inoculated kimchi at the early stages of fermentation, but overall there were no significant differences in the late phases. Also, the diversity and richness of bacterial communities varied depending on the various types of kimchi, and these differences could largely be explained by the major ingredients and the manufacture processes of each types of kimchi. This study provides the comprehensive understanding of the factors influencing the biodiversity of the kimchi ecosystem. © 2011 Elsevier Ltd.

Ahn J.,Korea Food Research Institute | Ahn J.,Korean University of Science and Technology | Lee H.,Korea Food Research Institute | Jang J.,Korea Food Research Institute | And 4 more authors.
Food and Chemical Toxicology | Year: 2013

Licorice (Glycyrrhiza glabra Linne) is a well-known medicinal plant and glabridin is an isoflavan isolated from licorice. In this study, we investigated the anti-obesity effect of glabridin and glabridin-rich supercritical fluid extract of licorice (LSC). Glabridin effectively inhibited adipogenesis in 3T3-L1 cells. Moreover, LSC showed inhibitory effect on adipogenesis in a dose-dependent manner. The inhibitory effect of LSC resulted from inhibiting the induction of the transcriptional factors CCAAT enhancer binding protein alpha and peroxisome proliferator-activated receptor gamma. Then we fed mice with high-fat diet containing none, 0.1% and 0.25% LSC for 8. weeks to explore the anti-obesity effect of LSC in vivo. LSC significantly reduced weight gain by high-fat diet in a dose-dependent manner. The reductions of the hypertrophy of white adipose tissue and of fat cell size were also observed. In the liver, LSC supplementation effectively inhibited high-fat diet-induced hepatic steatosis through downregulation of gluconeogenesis related phosphoenolpyruvate carboxykinase and glucose 6-phosphatase and upregulation of the β-oxidation related carnitine palmitoyltransferase 1. Taken together, our results suggest that glabridin and glabridin-rich licorice extract would be effective anti-obesity agents. © 2012 Elsevier Ltd.

Khan N.,Chosun University | Choi J.Y.,Chosun University | Nho E.Y.,Chosun University | Jamila N.,Universiti Sains Malaysia | And 4 more authors.
Food Chemistry | Year: 2014

This study aimed at analyzing the concentrations of 23 minor and trace elements in aromatic spices by inductively coupled plasma-mass spectrometry (ICP-MS), after wet digestion by microwave system. The analytical method was validated by linearity, detection limits, precision, accuracy and recovery experiments, obtaining satisfactory values in all cases. Results indicated the presence of variable amounts of both minor and trace elements in the selected aromatic spices. Manganese was high in cinnamon (879.8 μg/g) followed by cardamom (758.1 μg/g) and clove (649.9 μg/g), strontium and zinc were high in ajwain (489.9 μg/g and 84.95 μg/g, respectively), while copper was high in mango powder (77.68 μg/g). On the whole some of the minor and essential trace elements were found to have good nutritional contribution in accordance to RDA. The levels of toxic trace elements, including As, Cd, and Pb were very low and did not found to pose any threat to consumers. © 2014 Elsevier Ltd. All rights reserved.

You B.R.,World Institute of Kimchi | Kim H.J.,World Institute of Kimchi
Journal of the Korean Society of Food Science and Nutrition | Year: 2013

This study is conducted to investigate the quality characteristics of kimchi with added Allium hookeri root (AHR) during a 56-day fermentation process at 4°C. AHR was added to salted cabbage at concentrations of 0, 5, 10, and 20% (w/w). The quality characteristics of the kimchi with added AHR were determined by measuring pH, acidity, salinity, reducing sugar, microbial amounts, and sensory evaluation. AHR had a higher level of crude lipid and potassium than other kinds within the Allium family. All kimchi with added AHR gradually decreased in the pH level compared to Baechu kimchi until 2 weeks, and kept a higher level of pH than Baechu kimchi until 8 weeks. Salinity showed a range of 1.87~2.43% over 8 weeks. The reducing sugar content showed no difference between all kimchi. In sensory evaluations, overall acceptance, taste and texture were highest in kimchi with added 10% AHR.

Choi I.H.,Pusan National University | Noh J.S.,Pusan National University | Han J.-S.,Pusan National University | Kim H.J.,World Institute of Kimchi | And 2 more authors.
Journal of Medicinal Food | Year: 2013

Vegetable-based diets have generally focused on their health benefits including negative associations with the serum cholesterol concentrations. The aim of this study was to investigate whether serum lipid concentrations are influenced by the amount of kimchi intake. For the study, 100 volunteers were assigned to 2 dietary groups, low (15 g/day, n=50) and high (210 g/day, n=50) kimchi intake, and were housed together in a dormitory for 7 days. Identical meals except with different amount of kimchi were provided and subjects were instructed to maintain their normal physical activity. Concentrations of fasting blood glucose (FBG), total glucose, total cholesterol and low density lipoprotein (LDL)-C significantly decreased in both groups after 7 days of kimchi intake, but the effects were dose dependent. Lipid lowering effects of kimchi were more profound in the subjects with total cholesterol and LDL-C level over 190 and 130 mg/dL, respectively, in both groups. FBG was significantly decreased in the high kimchi intake as compared to the low intake group (P=.003). In conclusion, greater consumption of kimchi improved FBG and serum total cholesterol in young healthy adults. © Mary Ann Liebert, Inc. and Korean Society of Food Science and Nutrition.

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