• The Korean Journal of Food And Nutrition
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• v.34 no.1
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• pp.58-68
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• 2021

This study investigated the microbial community and quality characteristics of traditional soybean pastes (doenjang) based on the aging period in Gyeongnam province. The samples were collected from seven regions in Gyeongnam Province (Goseong, Hadong, Haman, Hamyang, Sacheon, Sancheong and Uiryeong). Contents of moisture, salinity, pH, and acidity of doenjang after 210 days aging were 56.40~65.21%, 9.05~16.08%, 4.88~6.86 and 0.64~2.14%, respectively. Lightness significantly decreased over the aging period, while the redness tended to increase over the aging period. Yellowness was from 21.39~26.81 to 21.10~28.36. Reducing sugar content was from 0.31~1.45% to 0.11~3.13%. The amino-type content increased from 141.87~495.13 mg/100 g to 328.53~823.67 mg/100 g. In contrast, the ammonia-type content declined from 136.74~364.70 mg/ 100 g to 128.62~331.00 mg/100 g. The overall total microbial count did not significantly differ, but it tended to decrease in sample GD4. Fungus declined overall or was not detected. Coliform groups were not detected in all samples. Lactobacillus and Bacillus cereus tended to decrease over the aging period. The common fungus and bacterium were Aspergillus oryzae and Tetragenococcus halophilus, respectively. After the aging period, the predominant fungi were Candida versatilis, Candida apicola, and Debaryomyces hansenii. The predominant bacteria were Tetragenococcus halophilus and Cronobacter sakazakii.

• Journal of Microbiology and Biotechnology
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• v.32 no.11
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• pp.1462-1470
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• 2022

Natural antimicrobial substances are needed as alternatives to synthetic antimicrobials to protect against foodborne pathogens. In this study, a bacteriocin-producing bacterium, Bacillus subtilis HD15, was isolated from doenjang, a traditional Korean fermented soybean paste. We sequenced the complete genome of B. subtilis HD15. This genome size was 4,173,431 bp with a G + C content of of 43.58%, 4,305 genes, and 4,222 protein-coding genes with predicted functions, including a subtilosin A gene cluster. The bacteriocin was purified by ammonium sulfate precipitation, Diethylaminoethanol-Sepharose chromatography, and Sephacryl gel filtration, with 12.4-fold purification and 26.2% yield, respectively. The purified protein had a molecular weight of 3.6 kDa. The N-terminal amino acid sequence showed the highest similarity to Bacillus subtilis 168 subtilosin A (78%) but only 68% similarity to B. tequilensis subtilosin proteins, indicating that the antimicrobial substance isolated from B. subtilis HD15 is a novel bacteriocin related to subtilosin A. The purified protein from B. subtilis HD15 exhibited high antimicrobial activity against Listeria monocytogenes and Bacillus cereus. It showed stable activity in the range 0-70℃ and pH 2-10 and was completely inhibited by protease, proteinase K, and pronase E treatment, suggesting that it is a proteinaceous substance. These findings support the potential industrial applications of the novel bacteriocin purified from B. subtilis HD15.

• Journal of the Korean Society of Food Culture
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• v.25 no.5
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• pp.598-606
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• 2010

Kimchi is the most well-known Korean traditional food, but it is also the main leftover of school lunch and dinner menus. This study aimed to familiarize teenagers with kimchi through school meals and to increase their daily kimchi intake, ultimately by appealing to the young generation's taste. A questionnaire survey was conducted in the Ansan area to examine student's acceptability of kimchi and their attitudes toward kimchi. Approximately 65% of males and 67% of female students liked the moderately fermented and pungent taste of kimchi. Kimchi served in school meals was regarded as nutritional but cheap. Approximately 72% of male and 82% of female students responded that they liked menu items using kimchi. Approximately 48% of students responded that menu items using kimchi in schools are not diverse. Students preferred meat as an ingredient in kimchi. The preferred cooking methods were stir-frying and frying, whereas boiling was the least favorite. Based on the survey results, ten kimchi menu items had been developed. The suitability of the menu was evaluated by students and cooks. Six kimchi items, including Kimchi mixed with rice, chicken, soybean sprouts, Kimchi cheese rice, stewed beef ribs with kimchi, rice topped with kimchi curry, kimchi cheese meat roast, and kimchi udong were considered appropriate for school meals, whereas kimchi kangchong, kimchi topokki, kimchi stew with surimi, and frozen Pollack kimchi soup were not suitable as menu items. Kimchi topokki was not accepted by students, while kimchi kangchong was not accepted by cooks. Cooks judged the suitability of a menu item by the cooking process and cooking times, whereas students judged an item by its sensory preference. Approximately 63% of students responded that kimchi intake has increased by participating in the development of kimchi dishes.

• Applied Biological Chemistry
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• v.22 no.2
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• pp.65-90
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• 1979

This study was conducted to establish the brewing method which would be useful for the production of Kochuzang. Kojis, which were made from various materials and microorganisms under a covered condition, were investigated and compared. Yeasts (Saccharomyces rouxii and Torulopsis versatilis) were added to Kochuzang, and the enzyme activity, microflora, chemical composition, nitrogen content, alcohol content and free sugars of Kochuzang were investigated and analysed. The results obtained are as follows: 1. Koji making (1) Glutinous rice-soybean group was superior to glutinous rice group in the saccharogenic and liquefying amylase activities of three day-Koji. (2) Protease activity (acid, neutral and alkaline) of glutinous rice-soybean Koji, which was inoculated with Aspergillus oryzae A, was increased till the 5th day, while other groups showed maximum activity after the 3rd day. (3) The maximum cellulose activity of Aspergillus oryzae B-Koji and A-Koji was observed after the 2nd day and the 3rd day, respectively. High cellulose activity of Aspergillus oryzae B-Koji and A-Koji was respectively shown in glutinous rice group and glutinous rice-soybean group at maximum. (4) Compared with glutinous rice Koji, glutinous rice-soybean Koji gave larger number of yeast and aerobic bacteria. 2. Kochuzang Fermentation (1) Each Kochuzang group shoved different liquefying and saccharogenic amylase activities. The highest activities were generally shown in 10 to 40 days after mashing and remarkably reduced in the last stage of aging. (2) Protease activities of each group were strong in order of acid, neutral and alkaline protease. Especially acid protease showed highest activity at the 40th to 50th day Kochuzang. (3) Each group showed maximum cellulase activity in the 40th and 50th day-Kochuzang and then decreased. (4) Osmophilic yeast of yeast-added Kochuzang after one-month aging was distinctively outnumbered compared with non-yeast-added Kochuzang, but two groups were similar after two months. (5) Yeast-added group and non-added group gave almost the same number of halophilic lactic acid bacteria in Kochuzang, but the non-added group gave slightly larger number of aerobic bacteria than the yeast-added group. (6) Amino nitrogen contents in all test group were increased rapidly till the 60th day of Kochuzang aged. After that the contents were increased slowly. (7) Ethyl alcohol contents of 20day-fermented Kochuzang were high in order of Saccharomyces rouxii-added group, Torulopsis versatilis-added group, Saccharomyces rouxii and Torulopsis versatilis mixed group and non-yeast-added group. But all test group showed about 2% in ethyl alcohol content after 40days of aging. (8) Alcohol content in the 7 month-aged Kochuzang of all test groups was high in order of ethyl alcohol, n-butyl alcohol, n-propyl alcohol and iso-propyl alcohol. Torulopsis versatilis-added group had the highest value of ethyl alcohol, n-propyl alcohol and n-butyl alcohol. (9) Reducing sugar in Kochuzang was increased after 20 days of aging compared with the 10days-ferment. The reducing sugar content in Saccharomyces rouxii-added group was distinctively small compared with that of other groups, decreasing after 30days of aging. (10) Rhamnose, fructose, glucose and maltose were isolated from the 10 day fermented Kochuzang. Raffinose was also found after 300 days-aged group, and fructose content was high in the 300days-aged Kochuzang. However, glucose content was smaller than that of 10days-fermented Kochuzang. (11) For the organoleptic tests of Kochuzang, taste, flavour and color of yeast-added group were superior to the non yeast-added group. Especially the complex yeast group among the yeast added groups were the best of all. Yeast-added group after 300 days of aging took higher paint in flavour test than that of non-added group. Therefore, brewing method like complex yeast added group seems to be advantageous for short time brewing Kochuzang.

• Food Science and Preservation
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• v.20 no.6
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• pp.818-826
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• 2013

To evaluate the practical use of okara koji in soy sauce fermented with soybean koji, the okara koji was fortified with different contents (0, 50, and 100%) in soybean koji and then fermented for 90 days. The saltiness of the soy sauce was about 17.15~17.22%. The higher okara koji content showed lower net soluble solid contents of 8.73, 6.12, and 2.50%, as well as lower acidity levels of 1.09, 0.98, and 0.47%. The buffering capacity of the soy sauce decreased to 1.26-3.41 by adding higher okara koji. The protease activity was higher in the soy sauce with 50% orara koji and decreased with longer fermentation. Also, the tyrosine content peaked to 275.2 mg% after 90 days. ${\alpha}$-amylase showed higher activity in the soy sauces fortified with okara koji, which resulted in the highest total sugar and reducing sugar contents after 60 days. The total sugar and the reducing sugar in the soy source decreased after longer fermentation. The total free amino acid contents of the soy sources fortified with okara koji (0, 50, and 100%) were 41.68 mg/mL, 33.10 mg/mL, and 9.27 mg/mL, respectively. In particular, the glutamic acid contents of the three types of soy sauces were highest, and most amino acids, except for glutamine, increased during the fermentation for 90 days. The sensory evaluation, except of the saltiness and color, showed similar values in the soy sauces, except in the okara koji 100%. Thus, okara koji could be a valuable ingredient of traditional soy sauces. However, the 50% okara koji did not differ significantly from the others.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.12
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• pp.1930-1939
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• 2013

It has been reported that Chungkukjang, one of Korean traditional fermented soybean products, may improve hypertension, diabetes, and hyperlipidemia. In this study, we sought to investigate the immunoenhancing effects of Chungkukjang in ovariectomized mice. For the first period, female SLC ddy mice were either sham-operated (Sham; n=27) or ovariectomized (OVX; n=27). As a basal diet, ovariectomized mice were fed low-calcium diet for faster induction of osteoporosis for six weeks, and those in the Sham group were fed AIN-76 diet. For the second period, half of the OVX group (n=9) and the Sham group (n=9) were fed a Chungkukjang-based diet (CKJ); whereas the other half (OVX; n=9/ Sham; n=9) were fed a casein-based diet (CSI) for 8 weeks. After a second period, we collected the blood via heart puncture and measured the splenocytes proliferation, T lymphocyte subsets by flowcytometry, and levels of serum cytokines (IL-2, IL-4, IL-6, IL-10, IFN-${\gamma}$ and TNF-${\alpha}$) by ELISA assay. The OVX+CKJ group showed higher splenocytes proliferation, higher ratio of CD4/CD8, and lower levels of IL-6 and TNF-${\alpha}$ cytokines compared to the OVX+CSI group. The Sham+CKJ group showed cytokine productions, such as higher levels of IL-10 and IFN-${\gamma}$, and lower levels of IL-6 and TNF-${\alpha}$ compared to the Sham+CSI group. The result of this study suggests that Chungkukjang may lower the proinflammatory cytokine levels in both the OVX and Sham groups. In addition, Chungkukjang could make a balance of T cell subset proliferations and enhance the splenocyte proliferations in the OVX group.

• Korean Journal of Microbiology
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• v.43 no.4
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• pp.298-303
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• 2007

Antithrombotic activities of water extract of cheongkookjang and cheongkookjang fermented with green tea or mugwort were evaluated on some antithrombosis related activities in vitro and thrombotic death inhibition in vivo. Cheongkookjang made of white soybean (Glycine max) or black small soybean (Rhynchosia nulubilis) showed potent antioxidative activities. Addition of green tea or mugwort during cheongkookjang fermentation increased the antioxidative activity, cheongkookjang with green tea showed more drastic increase compared with cheongkookjang with mugwort. Nitrite scavenging effects of the cheongkookjang extracts were prominent but the addition of green tea or mugwort seldom increased the scavenging effects. All the cheongkookjang extracts showed strong inhibitory activities on platelet aggregation. The inhibitory activities of cheongkookjang were increased considerably by addition of green tea or mugwort even with low concentration. Plasmin unit as fibrinolytic activity was not affected considerably by addition of green tea. Addition of mugwort decreased the activity transiently at low concentration ($0.3{\sim}1.0%$) but increased again slowly at higher concentration ($1{\sim}3%$). In vitro thrombotic death inhibition test, the antithrombotic activity of cheongkookjang made of black small bean with green tea was higher by about 1.5 times compared to that without green tea. As results, cheongkookjang might inhibit antithrombosis not only by fibrinolytic action but also by inhibition of platelet aggregation and antioxidative action. The addition of functional materials such as green tea or mugwort could increase the antithrombotic function, even at low concentration.

• Journal of the Korean Society of Food Culture
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• v.18 no.1
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• pp.56-68
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• 2003

The objects of this study are to find out (1) real situation of the food supply in prison under Imperial Government of Japan more cleary (historical meaning) and (2) which might help in understanding wrong present food consumption patterns in Korea which causes environmental as well as health problems. It is generally known that the length of the Japanese occupation for Korea is 36 years. However, it is concluded in this study that it was longer (70 years ; from 1875 to 1945 from when Japanese Army attacked and occupied Yungjongdo and Kanghwado island to e time when they were defeated on World War II.) Korea was annexed by Japan in 1910 then the Imperial Government of Japan dismissed the Korea Army, controlled the Office of Justice and the management of prison by force. Since then about 50% of all land was fell into Japanese Government ownership and 80% of Korean farmers became as tenant. After this change, Korea farmers were forced to pay extremely high rent (up to 80% of its harvest). Forced immigration, low price procurement of grain by Japanese government up to more than 30%of their production, was practiced. Accordingly, the food situation of Korean farmers became miserable, which may caused more violations of Imperial Japanese Law. Malnutrition, epidemic diseases, mortality rate of infants soared and average life expectancy shortened to 20-30 years old. This was the period of World Economic Crises and Food Crises in Japan. It was said then that if one Japanese comes to Korea then 200 Koreans will starved to death. Meanwhile, Proconsul Bureau of Chosun requested to the Department of Medicine, the Imperial University of Kyungsung to survey food supply situation of Koreans in prison throughout Korea. Objectives of the survey then was not only to find out scientifically whether it is agreeable in maintaining prisoner's health and also find out the possibility to save food during food crisis. Survey was started from 1923 and ended in 1945, and it focussed on prisoners in the Seodaemoon Prison. This report is the outcome of the first survey. They concluded that the food supplied was nutritionally (had) no problem, in compare with those of workers in the factory, students in the dormitory in Japan and with those of prisoners in Taiwan, France and Germany. Amount of grain supplied were different according to their work lord and was divided into 9 different levels. Total grain was consisted of 50% millet, 30% soybean and 20% indica rice(variety). However, there were no difference in the amount of supply of side dishes between work groups. For the highest working group, 3280g of boiled grain per day was supplied to make stomach full but as a side dishes, salty fermented bean paste, fermented fish and salty soups, etc. was supplied. Deficiency of animal protein were observed, however, high intake of soybean may possibly caused animal protein deficiency problem. On the contrary, the intake of water soluble vitamins were insufficient but the level of calcium and iron intake seems to be sufficient, however, imbalance of intake of nutrition may caused low absorbtion rate which might caused malnutrition. High intake of dietary fiber and low intake of cholesterol may possibly prohibited them from so called modem disease but may caused the defect in disease resistancy againist epidemics and other traditional disease. Over intake of salt(20-30g per day) was observed. Surveyors who attended in this survey, mentioned that the amount of food intake may nutritionally be sufficient enough but the quality of food(and possibly, the taste of food) were like that of animal feed. For the officials who received this report might consider that considering the war situation and food crisis, the supply situation of food in the prison may considered to be good enough(because they are not starving). But as a Korean who studied this report, one feel extremely pity about those situation because (situation of) those period were very harsh under the Imperial Law and keeping the Law by Koreans were almost impossible, therefore, about one third adult violated the Law and were put into jail. And they were treated like animals.

• Korean Journal of Food Science and Technology
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• v.29 no.3
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• pp.581-587
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• 1997

For bifidus fermentation food, gelatinized rice solution was fermented without liquefaction/saccharification by amylolytic Bifidobacterium spp. isolated from Korean. Eighteen amylolytic Bifidobcterium on the starch agar were isolated from 38 Korean and four strains were finally selected as good amylase producers. The most enzyme-producing strain of Bif. sp. FBD-12 secreted extracellular amylase of 0.17 U/mg and intracelluar amylase of 1.8 U/mg. Three strains of Bif. sp. FBD-12, Bif. sp. FBD-16 and Bif. sp. FBD-17 also showed good growth on pH controlled media by HCI/acetic acid to pH 5.0 while Bif. sp. FBD-6 was not so tolerant that viable cell counts reduced to $10^2\;CFU/mL$ times on the media. Initial cell number of $10^6\;CFU/mL$ for those strains reached to $10^9\;CFU/mL$ on the rice medium supplemented with yeast extract (0.2%) and cysteine (0.05%). Ascorbic acid instead of cysteine was added to the medium for improving off-flavour and the best growth was shown at 0.1% addition. Isolated soybean proteins (ISP) of 3% accelerated the growth of the strains. Maximum count of $10^9\;CFU/mL$ reached within 12 hour fermentation on the rice medium with ascorbic acid and isolated soybean protein instead of 32 hours on the cysteine medium, and total acidity increased from 0.5% to 1% on each media. Reducing sugar in the ascorbic acid/ISP cultures generally increased especially 2 mg/mL to 15.5 mg/mL for Bif. sp. FBD-6. From sensory evaluation, the products showed good acceptability so that it suggested possibility of development of bifidus-fermented rice food.