Hae Woong Park

Weissella cibaria WIKIM28 ameliorates atopic dermatitis-like skin lesions by inducing tolerogenic dendritic cells and regulatory T cells in BALB/c mice.

The occurrence of atopic dermatitis (AD), a chronic inflammatory skin disease, has been increasing steadily in children and adults in recent decades. In this study, we evaluated the ability of the lactic acid bacterium Weissella cibaria WIKIM28 isolated from gatkimchi, a Korean fermented vegetable preparation made from mustard leaves, to suppress the development of AD induced by 2,4-dinitrochlorobenzene in a murine model. Oral administration of W. cibaria WIKIM28 reduced AD-like skin lesions, epidermal thickening, and serum immunoglobulin E levels. Furthermore, the production of type 2 helper T (Th2) cytokines such as interleukin (IL)-4, IL-5, and IL-13 decreased in peripheral lymph node cells. Moreover, the intake of W. cibaria WIKIM28 increased the proportion of CD4+CD25+Foxp3+ regulatory T (Treg) cells in mesenteric lymph nodes (MLNs) and IL-10 levels in polyclonally stimulated MLN cells. In conclusion, the oral administration of W. cibaria WIKIM28 isolated from gatkimchi ameliorated AD-like symptoms by suppressing allergic Th2 responses and inducing Treg responses. These results suggest that W. cibaria WIKIM28 may be applicable as a probiotic for the prevention and amelioration of AD.

Effect of tempering methods on quality changes of pork loin frozen by cryogenic immersion

The quality characteristics of pork loin frozen by cryogenic immersion were examined, such as the drip loss, cooking loss, water holding capacity, moisture content, protein solubility, lipid and protein oxidation, color, and microstructure, and compared after different tempering methods: radio frequency (27.12MHz), water immersion, forced-air convection, and microwave tempering. Forced-air tempering was the most time-consuming process, whereas electromagnetic energy methods (radio frequency and microwave) were the shortest. The tempering rate of radio frequency at 400W was 5 and 94 times greater than that obtained with water immersion and forced-air tempering, respectively. The drip loss, water holding capacity, moisture content, color, and microstructure of pork samples all declined as a result of microwave tempering. By contrast, the least degree of changes in the drip loss, microstructure, and color of the pork loin samples was obtained with radio frequency tempering, suggesting its potential application in providing rapid defrosting without quality deterioration in the frozen meat industry.

Extending the shelf life of kimchi with Lactococcus lactis strain as a starter culture

Lactococcus lactis subsp. lactis WK11 was introduced as a starter in kimchi fermentation to investigate the role of starter cultures in extending the shelf life of kimchi. Kimchi, with an initial inoculum size of 107 CFU/g as well as control kimchi without the starter culture, were prepared and fermented for 56 days at 8°C. The addition of L. lactis prolonged the optimal fermentation period (pH 4.2, acidity 0.6–0.8%) up to more than 2 times. The starter culture, L. lactis WK11, persisted throughout the kimchi fermentation, as confirmed by regular monitoring of the L. lactis population by PCR-DGGE. Taken together, our results suggest that L. lactis starter culture may be useful for extending the shelf-life of kimchi without adverse effects of kimchi with a longer shelf life.

Protective effect of soy powder and microencapsulation on freeze-dried Lactobacillus brevis WK12 and Lactococcus lactis WK11 during storage

Food-grade cryoprotective agents, i.e., skim milk, soy powder, yeast extract, and trehalose were tested for viability of lactic acid bacteria (LAB, Lactobacillus brevis WK12 and Lactococcus lactis WK11) during freeze drying. Ten percentage of soy powder showed a strong protective effect upon viability of both LAB, showing 1.85×1011 CFU/mL for L. brevis WK12 and 1.89×1011 CFU/mL for L. lactis WK11. Microencapsulation in Ca-alginate beads increased viability of LAB, compared to nonencapsulated cells. Moreover, there was a synergetic effect on the stability of LAB when encapsulated LAB in Ca-alginate beads were soaked in 10% of soy powder prior to freeze-drying. When temperature increased, however, survival of LAB decreased. Four weeks after storage the highest viability was observed at -18°C for L. brevis WK12 and L. lactis WK11, showing 1.80×1011 CFU/mL and 1.78×1011 CFU/mL, respectively. These results suggest that soy powder may be useful for enhancing viability of LAB with microencapsulation.

Evaluation of ginsenoside bioconversion of lactic acid bacteria isolated from kimchi

Background Panax ginseng is a physiologically active plant widely used in traditional medicine that is characterized by the presence of ginsenosides. Rb1, a major ginsenoside, is used as the starting material for producing ginsenoside derivatives with enhanced pharmaceutical potentials through chemical, enzymatic, or microbial transformation. Methods To investigate the bioconversion of ginsenoside Rb1, we prepared kimchi originated bacterial strains Leuconostoc mensenteroides WiKim19, Pediococcus pentosaceus WiKim20, Lactobacillus brevis WiKim47, Leuconostoc lactis WiKim48, and Lactobacillus sakei WiKim49 and analyzed bioconversion products using LC-MS/MS mass spectrometer. Results L. mesenteroides WiKim19 and Pediococcus pentosaceus WiKim20 converted ginsenoside Rb1 into the ginsenoside Rg3 approximately five times more than Lactobacillus brevis WiKim47, Leuconostoc lactis WiKim48, and Lactobacillus sakei WiKim49. L mesenteroides WIKim19 showed positive correlation with β-glucosidase activity and higher transformation ability of ginsenoside Rb1 into Rg3 than the other strains whereas, P. pentosaceus WiKim20 showed an elevated production of Rb3 even with lack of β-glucosidase activity but have the highest acidity among the five lactic acid bacteria (LAB). Conclusion Ginsenoside Rg5 concentration of five LABs have ranged from ∼2.6 μg/mL to 6.5 μg/mL and increased in accordance with the incubation periods. Our results indicate that the enzymatic activity along with acidic condition contribute to the production of minor ginsenoside from lactic acid bacteria.

Complete Genome Sequence of Pediococcus pentosaceus Strain wikim 20, Isolated from Korean Kimchi

ABSTRACT Pediococcus pentosaceus strain wikim 20 is a lactic acid bacterium that was isolated from kimchi, a representative traditional Korean fermented food. Here, we announce the complete genome sequence of P. pentosaceus strain wikim 20 consisting of a 1,830,629-bp chromosome and provide a description of its annotation.

Use of Food-Grade Protective Agents to Improve the Viability of Freeze-Dried Lactic Acid Bacteria

Food-grade protective agents, namely, skim milk, yeast extract, soy powder, and trehalose, were studied for their ability to improve the viability of freeze-dried lactic acid bacteria (LAB), including Weissella cibaria SW1-1, Lactobacillus plantarum A-1, Lactobacillus sakei 2-12 24, and Leuconostoc citreum 3526. The best results were obtained with 10% soy powder; approximately 90% cell viability was observed during the freeze-drying process. Increase in the concentration of soy powder did not cause a proportional increase in the survival rate of LAB. Further, no significant difference was observed when two agents were combined in a 1:1 ratio (p<0.05).

Draft Genome Sequence of Lactobacillus sakei Strain wikim 22, Isolated from Kimchi in Chungcheong Province, South Korea

ABSTRACT We report the draft genome sequence of Lactobacillus sakei strain wikim 22, a Lactobacillus species isolated from kimchi in North Chungcheong Province, South Korea, having 155 contigs with 2,447 genes and an average G+C content of 40.61%.

Draft Genome Sequence of Lactobacillus plantarum wikim18, Isolated from Korean Kimchi

ABSTRACT This report describes the draft genome sequence of Lactobacillus plantarum strain wikim18, isolated from the traditional Korean food kimchi. The reads generated by Ion Torrent PGM were assembled into 327 contigs. RAST annotation of the genome revealed 12 tRNAs and 3,316 protein-coding gene sequences.

Gracilibacillus kimchii sp. nov., a halophilic bacterium isolated from kimchi

A novel halophilic bacterium, strain K7T, was isolated from kimchi, a traditional Korean fermented food. The strain is Gram-positive, motile, and produces terminal endospores. The isolate is facultative aerobic and grows at salinities of 0.0–25.0% (w/v) NaCl (optimum 10–15% NaCl), pH 5.5–8.5 (optimum pH 7.0–7.5), and 15–42°C (optimum 37°C). The predominant isoprenoid quinone in the strain is menaquinone-7 and the peptidoglycan of the strain is meso-diaminopimelic acid. The major fatty acids of the strain are anteisio-C15:0, iso-C15:0, and, C16:0 (other components were < 10.0%), while the major polar lipids are diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, and three unidentified lipids. A phylogenetic analysis of 16S rRNA gene sequence similarity showed that the isolated strain was a cluster of the genus Gracilibacillus. High levels of gene sequence similarity were observed between strain K7T and Gracilibacillus orientalis XH-63T (96.5%), and between the present strain and Gracilibacillus xinjiangensis (96.5%). The DNA G+C content of this strain is 37.7 mol%. Based on these findings, strain K7T is proposed as a novel species: Gracilibacillus kimchii sp. nov. The type strain is K7T (KACC 18669T; JCM 31344T).