• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.2
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• pp.161-167
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• 2013

The aim of this study was to investigate the protective effects of methanolic extract from perilla (Perilla frutescens Britt var. japonica) leaves (PLME) on oxidative injury from hydrogen peroxide ($H_2O_2$) in human HaCaT keratinoctyes. Cells were co-incubated with various concentrations (0~200 ${\mu}g/mL$) of PLME for 24 hr, and then exposed to $H_2O_2$ (500 ${\mu}M$) for 4 hr. $H_2O_2$ significantly decreased cell viability (p<0.05). However, PLME provided protection from $H_2O_2$-induced HaCaT cell oxidation in a dose-dependent manner. To further investigate the protective effects of PLME on $H_2O_2$-induced oxidative stress in HaCaT cells, the cellular levels of lipid peroxidation, and antioxidant enzymes (including superoxide dismutase (SOD), glutathione peroxidase (GSH-px) and catalase (CAT)) were measured. PLME decreased cellular levels of lipid peroxidation, and also increased the activities of antioxidant enzymes. In addition, the antioxidant activities of PLME were also determined by DPPH and hydroxyl (${\cdot}OH$) radical scavenging assay, and major antioxidant compounds of PLME were measured by colorimetric methods. DPPH and ${\cdot}OH$ radical scavenging activities of PLME increased in a dose dependent manner and was similar to the DPPH scavenging activity of ascorbic acid at 50 ${\mu}g/mL$; however PLME activities were stronger than ascorbic acid (50 ${\mu}g/mL$) in the ${\cdot}OH$ scavenging assay. The amounts of antioxidant compounds, including total polyphenolics, total flavonoids, and total ascorbic acid from PLME were $52.2{\pm}1.1$ mg gallic acid (GAE)/g, $33.7{\pm}4.7$ mg rutin (RUE)/g, and $17.0{\pm}0.5$ mg ascorbic acid (AA)/g, respectively. These results suggest that PLME has a strong free radical-scavenging activity and a protective effect against $H_2O_2$-induced oxidative stress in the keratinocytes.

• Microbiology and Biotechnology Letters
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• v.28 no.1
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• pp.39-44
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• 2000

This study was carried out to develop a new starter culture for the fermented meat products. Nine strains of lactic acid bacteria isolated from kimchi inhibited the growth of Listeria monocytogenes. Among these nine strains, three strains showing antimicrobial activities against Escherichia coil, Staphylococcus aureus and Vibrio paraphaemolyticus were selected for further study. Growth of the strains was inhibited in MRS broth containing 5% of NaCl at $21^{\circ}C$, but not at $32^{\circ}C$. Nitrite depletion ratio of the strains was above 70% after 48h incubation at $21^{\circ}C$, and above 90% after 48h at $32^{\circ}C$ in MRS broth containing $200\mu$g/ml of nitrite, Nitrite concentration of cured meats and ground meats was depleted from 87.6% to 92.3% and from 45.5 to 640.6% by addition of the selected strains for 24h at $32^{\circ}C$, respectively. Three strains were identified as Lactobacillus plantarum(N4) and Lactobacillus lactis ssp. lactis(N-7, an-8).

• Journal of Nutrition and Health
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• v.34 no.7
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• pp.797-808
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• 2001

To determine folate intake and food sources in Korea college students, dietary survey was conducted in March, 1999. Dietary data were collected by trained interviewers using the method of 24-hour recalls for 3 consecutive days. The data of 44 male and 62 female students were analyzed with two different nutrient databases in Recommended Dietary Allowances for Korean on the 6th and 7th revisions, and the results were compared. The intakes of energy and nutrients except vitamin A and folate were lower when analyzed with the 7th database than the 6th database. Mean daily folate intakes with the 6th and 7th databases were 172.9$\mu\textrm{g}$, 221.6$\mu\textrm{g}$ for male students while 125.1$\mu\textrm{g}$, 168.0$\mu\textrm{g}$ for female students, respectively. The results showed significantly higher estimates of folate intake with the 7th database, and significantly higher intake in males than females analyzed with both the 6th and 7th databases. Daily folate intake per 1,000kcal (folate density) was 71.1$\mu\textrm{g}$/1000kcal for males and 67.6$\mu\textrm{g}$/1000kcal for females with the 6th database, and 97.9$\mu\textrm{g}$/1000kcal for males and 95.5$\mu\textrm{g}$/1000kcal for females with the 7th database. The differences in folate density between the two databases were signficant, but the differences between the gender were not significant. The proportions of the subjects who consumed more than the RDA of 250$\mu\textrm{g}$ with the 6th and 7th databases were only 4.6%, 29.6% of males and 1.6%, 9.7% of females, respectively. The biggest food source of folate was Kimchi, contributing 17.9% for male and 13.7% for female students with 7th database. Laver, spinach, Ramyon, rice, and Ko Chu Jang together with Kimchi contributed 41.9% for male and 32.4% for females students with the 7th database. These results imply that folate intake reported in the reported inthe previous studies using the 6th database was underestimated. However, the 7th database seems to be still incomplete since 20.5% of 2,932 foods in the database were derived from the other sources, and the rest were imputed from similar foods. Therefore, in order to accurately estimate folate intake of Koreans, folate contents in major contributing foods need to be measured using an appropriate assay method.

• Korean Journal of Food Science and Technology
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• v.34 no.6
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• pp.1085-1090
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• 2002

Leuconostoc mesenteroides, the major bacterium in the initial phase of lactate-fermentation in kimchi, produces lactic acid, acetic acid, mannitol, and $CO_2$. It also secrets dextransucrase, which catalyzes the transfer reaction of glucose from sucrose to maltose, synthesizing mainly panose ($6^_2-{\alpha}-D-glucopyranosylmaltose)$, a probiotic oligosaccharide. To use the strain as a starer culture to produce high amount of panose during kimchi fermentation, we screened psychrotrophic strains showing fast growth rate at low temperature among the isolates of Leuconostoc sp. and selected two strains showing high dextransucrase activity. The strains were identified as Leuconostoc mesenteroides, which can be used as function added-starters for lactate-fermented foods.

• Journal of Bio-Environment Control
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• v.27 no.2
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• pp.125-131
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• 2018

The effect of 1-methylcyclopropene (1-MCP) in the storability of kimchi cabbage at cold storage condition was investigated. Kimchi cabbage (Brassica campestris L. cv Ryouckgwang) was divided four groups, forced air cooling (FAC), FAC + 0.03 mm linear low density polyethylene liner (Liner), $FAC+2{\mu}L{\cdot}L^{-1}$ 1-MCP (1-MCP), and FAC + 1-MCP + Liner. After each treatment kimchi cabbage was stored at $2^{\circ}C$, 95% RH. Quality parameters were weight loss, soluble solids content (SSC), firmness, and color ($CIE\;L^*$, $a^*$, $b^*$, chroma, hue angle). Weight loss during storage was showed significant difference by Liner treatment. In particular FAC + 1-MCP + Liner treatment showed 12.5% reduction after 6 weeks of storage period and minimized the weight loss rate compared to other treatments. SSC of kimchi cabbage was $2.5^{\circ}Brix$ at harvest and FAC + 1-MCP + Liner treatment maintained the SSC until 3 weeks, while in other treatments gradually were increased. The firmness of kimchi cabbage was 24.0 N immediately after harvest and the firmness at harvest time tended to be maintained at 22.6 N after 6 weeks of storage in FAC + 1-MCP + Liner treatment. During the storage period, the color change of the kimchi cabbage leaf can be confirmed by $CIE\;a^*$ and hue angle value. 1-MCP treatment alone did not affect the color change, however 1-MCP + Liner treatment was able to maintain the chromaticity at harvest time while minimizing the change of $CIE\;a^*$ and hue angle. These results suggest that 1-MCP treatment is not effective for the storage of kimchi cabbage but can be maintained for up to 6 weeks when treated with Liner.

• Journal of Dairy Science and Biotechnology
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• v.31 no.2
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• pp.143-152
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• 2013

Aminobutyric acid (GABA), a major inhibitory neurotransmitter in the central nervous system of animals, has several physiological effects including anti-hypertensive, diuretic, tranquilizing, and anti-stress properties, in humans. The purpose of this study was to investigate Lactobacillus plantarum K74, which was isolated from kimchi and selected as a strain with a high ability to produce GABA, to develop a new starter culture for fermented milk production. L. plantarum K74 produced $134.52{\mu}g/mL$ GABA in MRS broth containing 1% MSG, $212.27{\mu}g/mL$ GABA in MRS broth containing 2% MSG, and $234.63{\mu}g/mL$ GABA in MRS broth containing 3% MSG. The optimum growth temperature of L. plantarum K74 was $34^{\circ}C$, reaching a pH of 4.4 after 18 hours of growth. L. plantarum K74 was most sensitive to novobiocin out of 16 different antibiotics tested, and was most resistant to kanamycin and polymyxin B. L. plantarum K74 did not produce ${\beta}$-glucuronidase, a carcinogenic enzyme, and was comparatively tolerant to bile juice and low pH. Furthermore, it displayed resistance to Escherichia coli, Salmonella typhimurium, and Staphylococcus aureus at rates of 54.9%, 46.3%, and 0.7%, respectively.

• Korean journal of food and cookery science
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• v.24 no.1
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• pp.84-91
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• 2008

In this study, Kimchi, soup and stew samples were collected from May to June, 2007, in the Jeonju area, and their salinity levels were analyzed. In addition, housewives were surveyed via questionnaire to assess food behaviors and consumption patterns. The average salinity of the Kimchi samples was $2.0{\pm}0.5%$. The average salinity of the soup/stew samples was $1.0{\pm}0.3%$ in the broth portion and $0.8{\pm}0.3%$ in the homogenized mixture of both broth and solids. The average salinity of all types of soup was $0.9{\pm}0.3%$, and that for stews was $1.1{\pm}0.3%;$ the average salinity of the stew was significantly higher than that of the soup (p<0.001). Beanpaste soup had a significantly higher average salinity $(1.0{\pm}0.3%)$ than clear soup $(0.8{\pm}0.3%)$ (p<0.05). The Food behavior scores of the respondents, with regard to sodium intake and salty taste preference, showed significant positive correlations to the salinity of the soup and stew samples (p<0.01). The consumption patterns of the Kimchi and soup/stews were also analyzed to determine whether there was a relationship to the saltiness of the food samples. The respondents were divided into two groups for each food category: Kimchi groups of below 2.0% salinity and above 2.1% salinity, soup/stew groups of below 0.8% salinity and above 0.9% salinity. The below 0.8% salinity soup/stew group used salt or soy sauce in meals significantly less frequently (p<0.01) than the above 0.9% salinity group. The lower salinity Kimchi and soup/stew groups gave significantly higher scores regarding answers that their Kimchi was 'bland' (p<0.05). The types of frequently consumed Kimchi were determined as Korean cabbage, Welsh, wild greens, radish, KKak Du Ki, and Yol Mu Kimchi. When compared to the above 2.1% salinity Kimchi group, the below 2.0% salinity Kimchi group gave higher scores regarding answers that they consumed 'more than half the broth in the bowel' and also gave significantly higher (p<0.01) scores in answering that they consumed only the solid ingredients, leaving the broth.

• Food Science of Animal Resources
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• v.33 no.5
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• pp.595-602
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• 2013

As a major inhibitory neurotransmitter of the central nervous system in animals, ${\gamma}$-aminobutyric acid (GABA) has several physiological functions, such as anti-hypertensive, diuretic, tranquilizer and anti-stress effects in human. In order to determine strains with high GABA producing ability and glutamate decarboxylase (GAD) activity, 273 bacteria were isolated from various types of Kimchi. Strain K255 contained $386.37{\mu}g/mL$ of GABA in MRS broth containing 1% MSG, $600.63{\mu}g/mL$ of GABA in MRS broth containing 2% MSG and $821.24{\mu}g/mL$ of GABA in MRS broth containing 3% MSG. It showed that K255 had the highest GABA production ability compared to other commercial lactic acid bacteria. K255 was identified as Lactobacillus plantarum based on its API carbohydrate fermentation pattern and 16S rDNA sequence. K255 was investigated for its physiological characteristics. The optimum growth temperature of K255 was $37^{\circ}C$and cultures took 13 h to reach the pH 4.4. K255 showed more sensitive to bacitracin in a comparison of fifteen different antibiotics, and showed most resistance to kanamycin and vancomycin. Moreover, it was comparatively tolerant to bile juice and acid and displayed resistance to Escherichia coli, Salmonella Typhimurium, Staphylococcus aureus, with rates of 30.8%, 29.7%, and 23.4% respectively. These results demonstrate that K255 could be an excellent strain for the production of functional products.

• Korean Journal of Agricultural and Forest Meteorology
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• v.20 no.1
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• pp.127-134
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• 2018

This study evaluated the effects of high air temperature and waterlogging duration on growth and yield of Kimchi cabbage. Air temperature treatments were applied with ventilation; optimal (set $20^{\circ}C$) and delayed ($30^{\circ}C$) in the greenhouses. The waterlogging treatment levels were implicated 0, 12, 24, 48, and 72 hours, respectively. The growth of Kimchi cabbage was significantly affected by waterlogging duration. The head weight decreased by combining severe waterlogging and high air temperature. Net photosynthetic rate under the combination of non-waterlogging and optimal air temperature was $22.6{\mu}mol\;CO_2{\cdot}m^{-2}{\cdot}s^{-1}$, which was the greatest, while that of 72 hours-waterlogging was rapidly decreased. The percentage of formality with 0, 12, and 24 hours-waterlogging was over 88%, however, those of 72 hours-waterlogging with optimal and delayed ventilation were 64 and 68%, respectively, which were dramatically reduced. The yields were more affected by waterlogging duration than air temperature treatment because of deducting as increased waterlogging periods. These results indicate that waterlogging treatment reduced the yield and quality of Kimchi cabbage, thus it will be feasible to enhance the harvest time when severe waterlogging in the field.

• Journal of the Korean Society of Food Culture
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• v.9 no.2
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• pp.137-142
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• 1994

Myrosinase in leaf mustard was purified and characterized to furnish a grounding information for utilizing the pungent taste and the potential antimicrobial capability of Dolsan leaf mustard to enhance the taste and storage life of kimchi. When myrosinase was purified from leaf mustard through a series of DEAE Sephadex, chromatofocusing and Con A Sepharose column chromatography, specific activity of the enzyme increased 7107-fold compared with that of crude enzyme preparation, and 18.8% yield was obtained. The purified myrosinase showed the optimum pH of 5.9, isoelectric point of 4.6, molecular weight of 129 kD, Km of 0.206 mM, and Vmax of $2.039\;{\mu}M{\cdot}min^{-1}{\cdot}mg\;protein^{-1}$, respectively. The optimum concentration of L-ascorbic for the maximum activity of the enzyme was 0.6 mM, and the enzyme activity decreased at a higher concentration of L-ascorbic acid than 0.6 mM, showing almost no enzyme activity at a L-ascorbic acid concentration of higher than 2.0 mM. Myrosinase activity in leaf mustard kimchi immediately after the kimchi was formulated was shown to be about 70 nmol/min/mg protein which decreased rapidly after 3 days of storage at $20^{\circ}C$, showing that less than half and almost none of the enzyme activity was retained in 4 and 10 days of storage, respectively.