• Korean Journal of Microbiology
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• v.37 no.2
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• pp.158-163
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• 2001

The effect of phosphate on the production of avermectin B1a was studied. Response surface methodology was applied to optimize the concentration of organic nitrogen sources. The portion of B1b in total avermectins was decreased from 5.8% to 3.0% by the addition of 1.5 g/ι inorganic phosphate to the production medium. Among organic nitrogen sources, soybean meal was the most effective on avermectin biosynthesis. Results showed that B1a productivity was increased by 44.8% in a laboratory scale fermenter cultivation of Streptomyces avermitilis YA99-40 through fed-batch process. A maximal B1a productivity was obtained by repeated 30 and 20 g/ι of glucose feeding at 136 and 206 hour, respectively. The B1a productivity was increased by 86.3% and the proportion of B1a in the total avermectins was improved from 38% to 45% with respect to the control process. These results would be very useful for enhancing productivity of B1a in an up-scaled processes.

• Korean Journal of Clinical Laboratory Science
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• v.55 no.3
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• pp.151-158
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• 2023

Erythritol is a sweetener produced by yeast from glucose and a natural sugar found in fermented foods such as mushrooms, wine, fruits, rice wine, and soy sauce. Correct information and basic data when producing or using products for preventing dental caries by checking the gene expression patterns of glucosyl transferase (GTF) and fructosyl transferase (FTF) of Streptococcus mutans in erythritol and other sweeteners it was implemented to provide. Erythritol inhibited the growth of Streptococcus mutans, which is involved in dental caries. When used as a sweetener to replace sucrose, erythritol had an excellent caries-preventative effect. In particular, erythritol reduced the expressions of gtfB, gtfC, gtfD, and FTF, which are related to the synthesis of extracellular polysaccharides, and thereby reduced the formation of dental plaque and the attachment rate of bacteria to tooth surfaces. The study shows erythritol has potential use as an anticariogenic sweetener that inhibits the mechanism underlying caries caused by Streptococci.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.2
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• pp.116-123
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• 2004

This study was conducted to investigate the changes in physicochemical and microbiological properties during fermenting process of organic fertilizer which was made from the mixture of organic materials such as sesame oil cake, fish meal, blood meal, rice bran, ground bone meal, and natural minerals such as illite, crusted oyster shell and loess. They were mixed and fermented for 70 days. The sesame oil cake and rice bran, major ingredients for organic fertilizers, consisted of 7.6 and 2.6% total nitrogen, 3.6 and 4.6% $P_2O_5$, 1.4 and 2.2% $K_2O$, respectively. The ground bone meal included 29.2% $P_2O_5$ and illite included 3.8% $K_2O$. Temperature of organic fertilizer during the fermentation rapidly increased over $50^{\circ}C$ within 2 days after mixing and stabilized similar to outdoor temperature after 40 days. Moisture content decreased from 36.3 to 16.0% after 1 month. C/N ratio of organic fertilizer slightly increased until 30 days and thereafter, it slowly decreased, It resulted from the faster decrease of total nitrogen concentration compared with organic matter. Concentration of $NH_4-N$ in organic fertilizer rapidly increased from 1,504 to $5,530mg\;kg^{-1}$, the highest concentration after 10 days. Meantime, $NO_3-N$ concentration was low and constant about $150mg\;kg^{-1}$ over the whole fermenting period. This result seemed to be due to the high pH. The organic ferfilizer fermented for 70 days was composed of 2.7% N, 2.8% $P_2O_5$, 1.8% $K_2O$, and 35.9% organic matter. Total populations of aerobic bacteria, Bacillus sp. and actinomycetes, after fermenting process, were $12.5{\times}10^{10}$, $45.5{\times}10^{5}$ and $13.6{\times}10^{5}cfu\;g^{-1}$ respectively. Pseudomonas sp. was $71.9{\times}10^{7}cfu\;g^{-1}$ at first, but it rapidly decreased according to the rise of temperature. Yeasts played an important role in the early stage of fermentation and molds did in the late stage.

• Journal of the Korean Society of Food Culture
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• v.1 no.3
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• pp.267-278
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• 1986

The evolution of Korean fish fermentation technology was reviewed from the old literatures and the on-going processes were surveyed. The principles involved in the traditional fermentation methods were explained by the recent scientific findings. The fish fermentation technology be classified into two groups; jeot-kal process, where. salt is the only material added to the fish for fermentation, and sik-hae process, where cooked cereals, garlic and red pepper powder are added to the salted fish. A total of 46 kinds of jeot-kal was identified in a survey, depending on the raw materials used. The characteristic feature of Korean jeot-kal process is to produce fermented products which still has original shape after 2-3 months of fermentation to be used for side-dishes of rice meal, as well as fish sauce by keeping these products for longer time (over 6 months) for severe ansymematic hydrolysis to be used for the subingredient of Kimchi (Korean fermented vegetable food). The taste of jeot-kal is formed by the protein hydrolymates due to the action of salt-tolerant Pediococcus, Bacillus, Halobacterlum etc. When the taste of jeot-kal deteriorates, yeasts appear to dominate. In ski-hae fermentation, the safety of preserved fish is kept by the rapid decrease in pH resulting from the acid fermentation of added cereals. The roles of cid forming bacteria and proteloytic bacteria are important. The fermentation is completed in 2 weeks and the excess production of acid during prolonged storage limits the taste acceptability. The fish fermentation technology in Korea stands at important position in Korean food science and technology. since the processes of jeot-kal and soysauce have same root in the principle of microbial proteolysis and the processes of sik-hae and Kimchi in the microbial acid production principles.

• Food Science and Preservation
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• v.15 no.6
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• pp.909-914
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• 2008

This study investigated microbial populations and the sensory quality of sikhae including globefish (GLS), flounder (FLS), gastropods (GAS) and whelks (WHS) during storage at 4C for 16 d following fermentation at 10C for 4 d. General bacterial numbers increased to 102 in GLS and FLS, and to 1045 in WHS and GAS after the 20 d fermentation/storage period. Lactic acid bacteria increased to 108 log cycle in GLS and FLS after 10 d ripening time, and reached this level in GAS and WHS after 15 d and 20 d, respectively. After 20 days the number of lactic acid bacteria in each of the four samples was 108. There were 104105 yeast cells/g in each of the four samples after 20 d. The number of Leuconostoc increased to over 108 log cycle after 10 d in GLS and FLS, and 15 days in GAS for WHS the increase was to 107 log cycle. The pH values of GLS, FLS, GAS and WHS 4.42, 4.56, 4.31 and pH 4.26, respectively. The Sikhae acidity for all four samples ranged from 1.551.85%. From the sensory evaluation the overall acceptability was in the order of FLS > GLS > GAS > WHS.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.3
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• pp.366-370
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• 2007

Wild grapes contain various organic acids, vitamins, and inorganic salts compared to other various fruits. Their anthocyanin compounds are also known to have excellent effects in preventing cancers and heart diseases. Wild grapes are supposed to be a superior material for wine fermentation. This study was performed for searching optimum conditions for producing wild grape wines to improve their quality and taste. Four wild strains were isolated from Muscat Bailey A, ‘Kyoho’ grapevine, and wild grapes. For wild grape wine production, an optimum initial sugar concentration was $24^{\circ}Brix$ and an optimum temperature was $24^{\circ}C$. Sensory characteristics of the wild grape wine were evaluated for incense, sour taste, astringency, and sweet taste. Quality properties of the wild grape wine produced under the optimized fermentation conditions were analyzed. Total sugar, polyphenol contents, and acidity of the wild grape wine were 50.00 mg/mL, 25.30 mg/mL, and 0.95%, showing higher value than those of commercial grape wines. Amino acids, tannins, alcohol contents, and pH were 1.80 mg/mL, 1.88 mg/mL, 12%, and 3.59, respectively. The optimum fermentation conditions can be used to improve quality of the wild grape wine.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.2
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• pp.223-228
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• 2011

Korean traditional rice wine, Makgeolli, has been widely consumed with increasing popularity in Korea. Also, there has been an increase in the varieties of Makgeolli for the younger generation. In this study, we examined the physicochemical and microbial properties of Makgeolli supplemented with cucumber during fermentation. Four hundred grams of cucumbers (20% of the total amount of rice) were grinded and added to the rice solution (2 kg rice and 3.12 L distilled water) along with the Nuruk (40 g) and yeast (14 g). After mixing the solution, it was fermented for six days in a water bath ($28^{\circ}C$). During the fermentation, the pH value of the cucumber Makgeolli fell from 5.88 to 3.94 on day-1, and steadily increased to a pH value of 4.48 by day-6. The total acidity of the cucumber Makgeolli sharply increased from 0.02 to 0.20% on day-1, and then slowly increased thereafter to 0.28% by day-6. After the 6-day fermentation, the L values of the control and the cucumber Makgeolli were similar. The total viable cell, lactic acid bacteria and yeast count of the control and the cucumber Makgeolli increased considerably after the 6-day fermentation process. Free sugar analysis showed that glucose contents decreased with increasing fermentation periods. The succinic acid content was the highest among all the organic acids. Thirty-nine volatile compounds were observed on the final day of fermentation in the cucumber Makgeolli.

• Journal of Food Hygiene and Safety
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• v.26 no.2
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• pp.166-170
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• 2011

Modem people have begun to have the nationwide interest in the rice wine called Makgeolri which is one of the traditional Korean alcoholic liquors. This study was performed to investigate the effects of San sung Makgeolri extract (SM) on antioxidation together with the determination of pH and dissolved oxygen (DO) in the progress of fermentation in the lipopolysaccharide(LPS)-treated rats. We examined the levels of SOD (superoxide dismutase), CAT (catalase), GPx (glutathione peroxidase) in liver homogenates and the histopathological observations in liver tissue. LPS-treated group markedly decreased the levels of SOD, CAT and GPx. But SM + LPS-treated group significantly increased the levels of them. Furthermore, the antioxidative effects of SM were supported by the histopathological observations in liver tissue which showed severe inflammation and necrosis in LPS-treated group, compared to the attenuated inflammation and necrosis in SM + LPS-treated group. This results suggested that SM could be a candidate of antioxidative material in spite of alcoholic liquors.

• The Korean Journal of Mycology
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• v.40 no.3
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• pp.164-173
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• 2012

For development of new high-value Korean traditional fermented food by using bioactive fungi and bacteria, Nuruk, Makgeolli and Cheonggukjang were prepared by mold, yeasts and bacteria from Korean traditional fermented foods and their physiological functionalities were investigated. Aspergillus oryzae N152-1 Nuruk showed the highest antihypertensive angiotensin I-converting enzyme inhibitory activity(57.2%), and Makgeolli made by Saccharomyces cerevisiae Y111-5 and commercial JS Ipguk (solid cultures of saccharifying enzyme-producing mold) was showed 42.0% of anti-obesity ${\alpha}$-glucosidase inhibitory activity. Among various Cheonggukjang, No 463 Cheonggukjang made by Brevibacterium iodinum NCDO 613(T) was showed the highest fibrinolytic activity (size of clear zone: 28 mm) and good anti-obesity ${\alpha}$-glucosidase inhibitory activity.

• Korean Journal of Food Science and Technology
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• v.33 no.1
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• pp.107-112
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• 2001

The various components of sigumjang were analyzed according to fermentation time. Aerobic bacteria were increased with fermentation time. Yeasts and molds were increased until 3 days after fermentation and then not changed. Six free sugars, 3 volatile organic acids and 6 non-volatile organic acids were detected. The content of free amino acids was $1,407.9{\sim}3,053.9\;mg%$. Glutamic acid was most abundant component among the amino acids, followed by phenylalanine, arginine and valine. The ratio of essential amino acid was $34.4{\sim}37.0\;mg%$. The content of mineral was $12,966.7{\sim}13,864.5\;mg%$. Potassium was the most abundant in quantity among the minerals in sigumjang except sodium which was added artificially. The principal fatty acids were linoleic acid, palmitic acid and oleic acid. The ratio of unsaturated fatty acids was $76.3{\pm}1.1%$. As a result of sensory evaluation, the highest score was obtained 3 to 5 days after fermentation.