• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.11
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• pp.1619-1625
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• 2012

The purpose of this study is to determine long-term storage conditions for winter kimchi. Kimchi was stored in a kimchi refrigerator for 6 months with or without fermentation. Four different temperature systems used were as follows: 5 days at $10^{\circ}C$ followed by storage at $-2.5^{\circ}C$ (F1), 1 day at $15^{\circ}C$ followed by storage at $-2.5^{\circ}C$ (F2), storage at $-1^{\circ}C$ (S1), or at $-2.5^{\circ}C$ (S2). Time periods required for F1, F2, S1, or S2 kimchi to reach pH 4.4 and acidity 0.6% were 2, 8, 12, and 22 weeks, respectively. Lactobacillus spp. growth on F1 and F2 kimchi was faster and greater than that on S1 and S2 kimchi, revealing a maximum concentration of 8~9 verses 6.8 log CFU/mL, respectively. However, Leuconostoc spp. were fully grown (8~9 log CFU/mL) on all four kimchi samples regardless of temperature, even at $-2.5^{\circ}C$, although the times required to reach maximum growth were different. Growth of Lactobacillus and Leuconostoc spp. both decreased after reaching maximum levels, except for F1 kimchi. Sensory evaluation results for 3 month storage showed that F1 kimchi was the best among kimchi samples in terms of appearance, acidic taste, carbonated taste, crispiness, and moldy smell. For 6 months of storage, F1 and S1 kimchi were the most highly evaluated among the kimchi samples. Sensory evaluation result for S1 kimchi stored at $-1^{\circ}C$ was comparable to that of F1 kimchi due to fully grown Leuconostoc spp. Acidities of F1 and S1 kimchi after 6 months of storage were 0.8 and 0.7%, respectively. Taken together, fermentation of kimchi at $10^{\circ}C$ for 5 days followed by storage at $-2.5^{\circ}C$ for 6 months was optimal for high quality kimchi. Sensory properties of winter kimchi were significantly influenced by the degree of fermentation.

• Korean Journal of Food Science and Technology
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• v.36 no.1
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• pp.123-128
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• 2004

Effects of jeotkal (salted-fermented seafoods) addition on acid production, growth of lactic acid bacteria, sensory properties, and volatile odor components of kimchi were investigated. Changes in pH and acidity of kimchi added with myulchi-aekjeot, kanari-aekjeot, and aekche-Jukjeot were similar to, whereas those of saeu-jeot sample on 0, 2, and 4 days of ripening were slightly different, those of control sample. Changes in pH and acidity of jogae-jeot sample during whole ripening period were markedly different from those of other samples. Numbers of lactic acid bacteria of all samples on 0 and 4 days were $1.8-2.6{\times}10^{5}\;and\;1.0-2.5{\times}10^{9}\;CFU/mL$, respectively. Overall acceptability and taste of kimchi added with jeotkal except jogae-jeot were higher than those of control sample, with saeu-jeot-added kimchi showing the highest scores. Eight volatile odor components were identified in 6-day-ripened kimchi samples, and those of saeu-jeot sample were slightly higher than those of other samples. Diallyl sulfide and methyl propyl disulfide were produced in 6-day-ripened samples. Ethanol, methyl allyl sulfide, and dimethyl disulfide concentrations increased, whereas that of allyl mercaptan decreased in 6-day-ripened samples compared to unripened ones.

• Journal of the East Asian Society of Dietary Life
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• v.19 no.5
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• pp.681-689
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• 2009

The purpose of this study was conducted to investigate the perception of Korean kimchi among Americans' living in different areas in the United States. A questionnaire was given to males 126 (40.4%) and females 186 (59.6%) residing in Illinois and California. The results were as follows: 86.0% of the participants answered that kimchi was Korean in origin, and 84.1% reported that they had eaten kimchi. Additionally, 56.8% and 52.3% of the respondents in Illinois and California had purchased commercial kimchi at home-made. Among the kimchi they had experienced, out of the total respondents, 92.4% had eaten baechu kimchi, 45.5% had eaten mu kimchi and 42.4% had eaten oi kimchi (When the responses from the residents of Illinois were evaluated: 100.0% of the respondents had eaten baechu kimchi, while 47.7% had eaten mu kimchi, and 40.9% had eaten bak kimchi. Evaluation of the responses of residents from California revealed that: 88.6% had eaten baechu kimchi, 45.5% had eaten oi kimchi, and 44.3% had eaten mu kimchi respectively). For evaluation of the their kimchi preference of the overall population revealed that, 71.0% preferred baechu kimchi, 9.2% oi kimchi, and 8.4% mu kimchi (Of the respondents in Illinois: 69.8% preferred baechu kimchi, 14.0% mu kimchi and 7.0% bak kimchi, while for Californians: 71.6% preferred baechu kimchi, 11.4% oi kimchi and 8.0% bak kimchi, respectively). Regarding the primary reason they purchased commercial kimchi, 64.9% responded 'its taste' (67.4% in Illinois and 63.6% in California), additionally, 40.0% stated of the package they purchased was 200g (51.2% in Illinois and 34.5% in California). After having eaten kimchi, 45.5% answer reported that it tasted good, and the their primary reason for liking kimchi was its, 'spicy and hot taste' (51.3%), The main reasons for not liking kimchi were the odor (garlic, ginger, anchovy juice, etc) and it being too spicy, respectively. Regarding improvements for its expanded consumption, 25.0% answered 'not to improve', 22.7% answered 'reduce the strength of the strong seasoning', and 20.5% answered 'to allow over-ripening'.

• Journal of Microbiology and Biotechnology
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• v.12 no.1
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• pp.166-171
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• 2002

The genus Leuconostoc is generally recognized as a favorable microorganism associated with a good taste of Kimchi and Lactobacillus plantarum is responsible for the overripening and acidification of Kimchi. A rapid and reliable PCR-based method to monitor the change of these lactic acid bacterial populations during Kimchi fermentation was attempted. A Leuconostoc-specific primer set was chosen from the conserved sequences of 16S rRNA genes among Leuconostoc species. The Lb. plantarum-specific primer set was the internal segments of a Lb. plantarum-specific probe which was isolated after randomly amplified polymorphic DNA (RAPD) analysis and tested for identification. The specificity of this protocol was examined in DNA samples isolated from a single strain. In agarose gel, as little as 10 pg of template DNA could be used to visualize the PCR products, and quantitative determination was possible at the levels of 10 pg to 100 ng template DNA. For the semi-quantitative determination of microbial changes during Kimchi fermentation, total DNAs from the 2 h-cultured microflora of Kimchi were extracted for 16 days and equal amounts of DNA templates were used for PCR. The intensities of DNA bands obtained from PCR using Leuconostoc-specific and Lb. plantarum-specific primer sets marked a dramatic contrast at the 1 ng and 100 ng template DNA levels during Kimchi fermentation, respectively. As the fermentation proceeded, the intensity of the band for Leuconostoc species increased sharply until the 5th day and the levels was maintained until the 11 th day. The sharp increase for Lb. plantarum occurred after 11 days with the decrease of Leuconostoc species. The results of this study indicate that Leuconostoc species were the major microorganisms at the beginning of Kimchi fermentation and reach their highest population during the optimum ripening period of Kimchi.

• Korean Journal of Food Science and Technology
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• v.38 no.1
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• pp.143-146
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• 2006

Effects of licorice (Glycyrrhiza uralensis) powder as sugar substitute on kimchi quality was evaluated by investigating acid formation, lactic acid bacteria growth, and sensory properties of licorice powder added kimchi. Initial pH of licorice powder added kimchi unripened and ripened for one day did not differ from those of other samples, but slightly increased thereafter 2-3 days ripening. Acidities of unripened and kimchi ripened for 1 day significantly increased by addition of licorice powder, while that of kimchi ripened for 2-3 days significantly decreased (p<0.05). Addition of licorice powder had no significant effect on lactic acid bacteria count of kimchi compared to sugar. Overall acceptability and taste of 0.1 and 0.2% licorice powder-added kimchi ripened for 1-3 days were similar to or slightly higher than those of reference sample, whereas addition of 1.0% licorice powder resulted in lowest overall acceptability, taste, odor, and texture. Licorice powder addition generally did not change color of kimchi.

• Journal of the Korean Society of Food Culture
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• v.22 no.1
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• pp.104-114
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• 2007

This research entailed collecting domestic and overseas research papers on technologies for fermentation of Kimchi, which is widely considered the national dish of Korea, creating a technology classification structure and conducting quantitative analysis on each technology component and schematization. Five research papers were published in domestic journals in 1990. Afterwards, the number increased by six to nine papers a year. There was no clear increase after the year 2000, but an average of around 20 papers have been Published every year, indicating that Kimchi research is now becoming widespread. An analysis on researchers entailed determining the percentage of research papers published by the top ten authors. The percentage was 76% in the early-1990s; 63% in the late-1990s; and 52% in the 2000s, indicating that Kimchi has been more and more widely researched and Kimchi research has become professionalized. Universities were found to be leading the research as 52% of researchers belonged to universities. Another 9% were at research institutions. Analysis of technologies showed that domestic research mainly focused on the Kimchi fermentation process and an additive for the development of new Kimchi ingredients and types, preservation and quality improvements. Most of the research papers published overseas dealt with the functions of bacteria strains isolated from Kimchi; and improvements in the Kimchi fermentation and ripening processes. And most of the research papers have been published in a field of microorganism and biotechnology.

• Korean journal of food and cookery science
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• v.30 no.1
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• pp.22-32
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• 2014

This study investigated the spicy hot flavor related quality characteristics of baechu (Kimchi cabbage) Kimchi prepared using hot pepper powder in various capsaicin levels during 8 weeks of storage. The pHs in the Kimchi samples were in the optimum range of the pH 4.2-4.5 due to the relatively low storage temperature of $2^{\circ}C$ during the entire storage periods. The L, a and b values of cap-150 sample group were significantly higher compared to those in the other samples at 8 weeks of storage. Grading hotness of the Kimchi was significantly clearly separated when varied levels of hotness for the hot pepper powder were used at 2-4 weeks of storage (p<0.001). Sensory spicy hotness of the cap-40 showed significantly the lowest with values of 4.57-4.38 representing mild hot:, that of cap-85 was medium hot with values of 5.81-6.00; and finally, that of cap-150 showed the values of 6.86-7.14, representing strong hot flavor at 2-4 weeks of storage (p<0.001). The grading of spicy hotness in the Kimchi increased by about one level at the optimal edible periods due to the leaching out of capsaicin from the hot pepper powder for those storage periods. Thus, the increased hotness of the Kimchi in the optimal edible periods should be considered when the desired hotness of the hot pepper is chosen for the Kimchi preparation. The hotness decreased as the organic acids were generated during ripening by the 8th weeks of storage.

• Korean Journal of Food Science and Technology
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• v.21 no.3
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• pp.331-337
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• 1989

In order to investigate the method for extension of shelf-life of Kimchi, the effect of low temperature heating and addition of mustard oil on pH and total acidity of Kimchi during storage at $15^{\circ}C$ were studied. Mustard oil was found to have the antimicrobial effect on the major lactic acid bacteria of Kimchi such as Lactobacillus plantarum, Lactobacillus brevis, Leuconostoc mesenteroides and Pediococcus cerevisiae, Addition of 200p.p.m. mustard oil, 0.1% mustard powder and 0.01% $H_2O_2$ to Kimchi effectively reduced the fermentation rate of Kimchi. Low temperature heating of salted cabbage and addition of 200p·p.m. mustard oil and 0.01% $H_2O_2$ to seasonings extented the time reaching optimum ripening of Kimchi about 2.5 times longer than control. Combination of low temperature heating, addition of mustard oil and $H_2O_2$ to seasonings and post low temperature heating delayed fermentation time Kimchi about 5 times longer than control after 15 days storage at $15^{\circ}C$.

• Journal of Food Hygiene and Safety
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• v.13 no.4
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• pp.332-336
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• 1998

The effect of ripening temperature, pH and salinity on the formation of Nnitrosamine (NA) during Kimchi fermentation and in vitro was studied, respectively. During Kimchi fermentation for six weeks at cold storage temperature ($4^{\circ}C$) and room temperature ($16{\pm}2^{\circ}C$), the contents of nitrite and dimethylamine (DMA) showed variation at room temperature but no variation at cold storage temperature. The maximum generation of nitrosodimethylamine (NDMA) resulted low content ($2.69\;\mu\textrm{g}/kg$) at cold storage temperature but started to increase after one week fermentation and reached to the 18-fold higher generation ($49.6\;\mu\textrm{g}/kg$) at room temperature. During Kimchi fermentation, no correlation was observed between the variation of nitrite and DMA content and the generation of NDMA. However, pH showed effective relation to NDMA generation such as the highest NDMA generation was obtained at lowest pH 4. During in vitro test, higher temperature and lower pH resulted more NDMA generation and generation amount was affected more by pH. Also, the salinity of Kimchi provided inhibitory effects on the formation of NDMA. NDMA was produced $5.86\;\mu\textrm{g}/kg$ at normal salinity (2.5%) but $90.9\;\mu\textrm{g}/kg$ at lower salinity (15%) after three week. The higher salinity showed lower formation of NDMA in vitro test, too.

• Food Science and Preservation
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• v.2 no.2
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• pp.277-284
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• 1995

To study the shelf-life of cut cabbage kimchi, we examined the several quality characteristics of cabbage kimchi under various storage temperatures and packing materials. The pH of kimchi extracts were decreased to 4.0 in the condition of storage at 8$^{\circ}C$ during 6 days, at 4$^{\circ}C$ during 18days, 0$^{\circ}C$ during 42 days. The increase patterns of the organic acid were reverse to the changes of pH under the all conditions. The contents of reducing sugar were continuously decreased at 8$^{\circ}C$ , but increased gradually at 0$^{\circ}C$ and 4$^{\circ}C$ storage conditions. The contents of vitamine C were decreased at the early storage but increased to optimum ripening stage of pH 4.2-4.4 and after decreased continuously. The total bacterial cell counts of cabbage kimchi were increased suddenly at the early storage and after decreased gradually. And at the higher storage temperature, the more lactic acid bacteria were. On the results of sensory evaluation of cabbage kimchi at marketable shelf-life, sour taste and sour smell were significant under all experimental conditions by Duncan's multiple range test. On the above all results, we concluded that the marketable shelf-life of cut cabbage kimchi were 42 days, 19 days, 6 days at 0$^{\circ}C$, 4$^{\circ}C$, 8$^{\circ}C$ storage condition respectively.