• Korean Journal of Food Science and Technology
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• v.52 no.5
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• pp.529-537
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• 2020

This study was carried out to confirm changes in the microbial community and physicochemical characteristics of Korean traditional Makgeolli during fermentation by yeast as a fermentation starter. We demonstrate that the microbial community during fermentation affects the quality of Makgeolli. At the species level, Pediococcus pentosaceus, Weissella confusa, Pantoea vagans, and Lactobacillus graminis were dominant on fermentation mix, after 1-2 days, in the control group without yeast treatment. Acid production in the control group was higher than that in the yeast-treated group. P. pentosaceus was dominant throughout the fermentation process, and the proportion of P. vagans remarkably decreased following yeast addition. Considering quality characteristics, the alcohol content rapidly increased after yeast addition, and the lactic acid content was lower in the yeast-treated group than in the control. These results suggest that the rapid increase in alcohol at the start of fermentation inhibits the growth of lactic acid-producing bacteria. The addition of yeast may contribute to the reduction in the high amount of lactic acid, which can be one of the causes of changes in Makgeolli quality.

• Food Science and Preservation
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• v.30 no.6
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• pp.1043-1055
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• 2023

This study was conducted to suggest an extraction method for preparing the extract from green tea leaves that possess enhanced antioxidant and antibacterial activities. Different ethanol concentrations were tested to recover phenolics and flavonoids, and 50% ethanol was the best under heat treatment (121℃, 15 min). The ethanol extract exhibited excellent DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity and growth inhibition against B. cereus, B. licheniformis, S. aureus subsp. aureus, and A. hydrophila subsp. hydrophila. To enhance the antioxidant and antibacterial activities, cell-wall degrading enzymes (2.5% cellulose+2.5% pectinase, v/w dry sample) treatment and Saccharomyces cerevisiae fermentation were applied singly or in combination. The enzymatic treatment of green tea leaves notably increased extraction yield. However, the antioxidant and antibacterial activities of the extract were lower than those of the control (heat-treated 50% ethanol extract). In contrast, the yeast fermentation alone did not affect the yield, but enhanced antioxidant and antibacterial activities, contributing to the increase in the extract's total phenolic and flavonoid contents.

• Journal of Life Science
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• v.18 no.4
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• pp.550-555
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• 2008

This study focused on alcohol fermentation properties of red ginseng extracts using Saccharomyces cerevisiae JF-Y3. Central composite design was employed to investigate the influence of red ginseng extract content ($10{\sim}50%$, v/v) and yeast extract ($0.5{\sim}2.5%$, w/v) on the properties of alcohol fermentation added with red ginseng extracts. Yeast cell growth was affected both by red ginseng extract content and yeast extract content, and red ginseng extract content had a greater effect on yeast cell number than yeast extract content. Yeast cell number increased along with decrease of the red ginseng extract content and with increase of yeast extract content. Alcohol content was maximal at 30% red ginseng extracts and 0.50% yeast extract and the predicted maximum value of alcohol content was 12.45%. Brix degree and total sugar content were significant within 1% level (p<0.01), and brix degree was affected both by red ginseng extract and yeast extract content. Total sugar content was significantly affected by red ginseng content.

• Culinary science and hospitality research
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• v.20 no.2
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• pp.100-119
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• 2014

In this study, rice was used with naturally fermented extract to compare and analyze the physico-chemical characteristics and investigated how to make pan bread made with domestic wheat flour added with naturally fermented rice extract. Also, it examined quality characteristics of pan breads prepared with 0, 10, 30, 50, 70% naturally fermented rice starters. As the fermentation time of rice starters increased, pH of bread doughs decreased. On farinograph, water absorption, development time and stability of rice starters samples were lower than the control. RVA(Rapid Visco Analyzer) analysis showed that wheat flour retrogradation was retarded by increasing rice starters content. The weights of pan breads containing rice starters were higher than that of control. The moisture content of pan breads containing rice starters decreased as storage time increased. In analyzing of visible mold colony during 7 days of storage at $28^{\circ}C$, pan breads containing rice starters was retarded mold growth. In the texture analyzer measurement, hardness of breads containing rice starters significantly increased as storage time increased, which was higher than that of control. The result of sensory properties was no significant difference between the group containing 50% naturally fermented rice starters and control group, such as appearance, flavor, taste and overall quality.

• Korean Chemical Engineering Research
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• v.46 no.5
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• pp.858-862
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• 2008

The Simultaneous Saccharification and Fermentation(SSF) of ethanol production from potato starch studied with respect to growth pH, temperature, substrate concentration. The glucoamylase and Saccharomyceses cerevisiae have a capacity to carry out a single stage SSF process for ethanol production. The characteristics, termed as starch hydrolysis, accumulation of glucose, ethanol production and biomass formation, were affected with variation in pH, temperature and starch concentration. The maximum ethanol concentration of 12.9g/l was obtained using a starch concentration 30g/l, which represent an ethanol yield of 86%. The optimum conditions for the maximum ethanol yield were found to be a temperature of 38, pH of 4.0 and fermentation time of 18hr. Thus by using the control composite design, it is possible to determine the accurate values of the fermentation parameters where maximum production of ethanol occurs.

• Korean Journal of Food Science and Technology
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• v.34 no.4
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• pp.647-651
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• 2002

Eleven salt replacements$(SR-1{\sim}SR-11)$ composed of NaCl, KCl, $MgSO_4,\;CaSO_4$, lysine or glutamic acid were prepared and used for the preparation of low salt Kimchi instead of NaCl alone. Some chemical and microbiological characteristics of the low-salt Kimchi with 2.5% salt replacement were determined during the fermentation at $20^{\circ}C$. The pH decrease and acidity increase of low-salt Kimchi were slower than those of control Kimchi with NaCl alone. The total number of microorganism in SR-8 Kimchi added L-lysine was lower than that of control Kimchi until 5 days of fermentation. However, there was no difference in the numer of lactic bacteria between low-salt Kimchi and control Kimchi. The growth of yeasts was found to be slow in low-salt Kimchi with SR-8. The low-salt Kimchi with SR-3 showed the hardest texture among the prepared Kimchi. The overall acceptabilities of low-salt Kimchi prepared with SR-1, SR-3 composed of NaCl, KCl, $MgSO_4,\;CaSO_4$, and SR-10 added 0.2% glutamic acid to the elements were similar to the control Kimchi.

• Korean journal of food and cookery science
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• v.17 no.6
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• pp.625-633
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• 2001

The purpose of this study was to investigate the growth of lactic acid bacteria and the self-life of Kimchi prepared with Toha sauce(TK) and different kinds of jeot-kal, a traditional fermented fish sauce. The Kimchi samples were stored for 42 days at 12$\pm$2$\^{C}$. The results were as follows: The pH value was decreased in the order of TK, AK(prepared with fermented anchovy juice), SK(prepared with fermented shrimp) and CK(control), and the acidity was increased in the opposed order. Redox potentials decreased until 4 days of fermentation but increased thereafter. TK showed the lowest value in redox potential as well as the lowest change in the number of yeast; however, it had the highest contents of vitamin C and reducing sugar. The total number of lactic acid bacteria was higher in jeot-kal-added Kimchi than control throughout the fermentation period. In sensory evaluation. AK got the highest score in overall preference in the early stage of fermentation, but TK was preferred in the late stage.

• Food Science and Preservation
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• v.17 no.5
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• pp.733-740
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• 2010

Brown rice vinegars were prepared by agitated or static acetic acid fermentation using different yeast strains (Saccharomyces kluyveri DJ97, Saccharomyces cerevisiae JK99, Saccharomyces cerevisiae GRJ, or Saccharomyces cerevisiae H9). Organic acid contents and levels of volatile compounds were compared in vinegars prepared by different methods. The chosen yeast strain did not significantly affect the organic acid content of vinegar. In vinegars prepared by agitated acetic acid fermentation, organic acid contents were, in the order of descending abundance, acetic acid, citric acid, lactic acid, oxalic acid, and tartaric acid. In vinegars prepared by static acetic acid fermentation, no citric acid was detected, and lactic acid content was higher than that in agitated acetic acid fermented vinegar. The volatile compounds of both vinegars, analyzed by GC-MS, did not significantly differ when various yeast strains were used. Eighteen volatile compounds were detected in vinegar prepared by agitated acetic acid fermentation and 11 in vinegar prepared by static fermentation. Volatile compounds that can affect vinegar quality, including ethyl acetate and phenethyl acetate, were present at high concentrations in static acetic acid fermented vinegar. Electronic nose analysis showed that volatile chemical patterns differed between the two types of vinegar, but there were no significant differences in sensory scores between vinegars prepared using various yeast strains or by either of the two methods of fermentation.

• Applied Biological Chemistry
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• v.46 no.4
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• pp.348-352
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• 2003

In this study, strain of high-producing intracellular glutathione was isolated from Korean traditional rice wine. The isolated strain was identified as Saccharomyces cerevisiae based on the morphological, physiological and biochemical characteristics, and was designated as FF-8. The optimal condition for glutathione production by Saccharomyces cerevisiae FF-8 was obtained after cultivation with shaking for 72 hours in the YM medium. The optimal temperature, shaking rate and initial pH for the glutathione production were $30^{\circ}C$, 100 rpm and pH 6.0, respectively. The dry cell weight and glutathione concentration produced by Saccharomyces cerevisiae FF-8 were 5.2 g/l and 72.0 mg/l, respectively, under the optimal culture condition.

• Microbiology and Biotechnology Letters
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• v.18 no.5
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• pp.511-516
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• 1990

A high-alcohol producing yeast strain had sugar and alcohol tolerance was isolated from soil and identified as Saccharomyces cerevisiae Dl according to the Lodder's yeast taxonomic studies. On investigation of the characteristics of the strain, it could grow in 60% glucose, within 15% ethanol and in the YPD medium containing 2.0 mM copper. It had 39.1% the inhibition rate of fermentation efficiency and 8% viability after 2 days in the YPD medium containing 15% ethanol. Its optimum initial pH, growth temperature, initial glucose concentration for the production of alcohol showed pH 4.5, $30^{\circ}C$, and 30%, respectively. Saa:hwomyce8 mvisiae Dl produced 14.0% (wlv) alcohol when incubated at $30^{\circ}C$, with orbital shaking 150 rpm for 72 h in a medium (pH 4.5) containing 30% (wfv) glucose.