• Preventive Nutrition and Food Science
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• v.7 no.1
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• pp.37-42
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• 2002

Factors affecting the production of bacterial cellulose and organic acids in Kombucha fermentation were investigated. Kombucha was obtained by the fermentation (for 12 days at 3$0^{\circ}C$) of the green/black tea extract, supplemented with 10% white sugar, using an Oriental tea fungus as starter. Hitgher initial pH increased acid production with decreased cellulose production. With a cellulose pellicle or tea fungus broth as a starter, a 1~3 mm thick cellulose layer developed as a top layer every four days, and was removed subsequently while continuing fermentation. Addition of 30 mL tea fungus broth (13%, v/v) in Kombucha fermentation resulted in maximum production of a cellulose pellicle, indicating weak acid production. Yield of cellulose production at an early stage of fermentation was also higher when Kombucha was inoculated with a cellulose pellicle. In fact, addition of 1% (v/v) alcoholic beverage in the Kombucha fermentation activated the cellulose production, coupled with four times higher acid production.

• Journal of Life Science
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• v.18 no.6
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• pp.871-877
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• 2008

Onions are considered to be a promising source of the alcoholic drink because they are rich in sugar, amino acids and various nutrients. To isolate strains of Saccharomyces cerevisiae producing ethanol of higher concentration, 19 strains were subjected to screening. Among them, the strain producing the highest concentration of ethanol was OJ-8 strain. Onion's oder was effectively removed by treatment for 30 min with 10% (w/v) charcoal against medium and then heat treatment of onion extract for 40 min at $100^{\circ}C$. The optimum conditions for alcoholic fermentation was investigated in medium containing the onion extract. The optimal conditions for ethanol production was obtained by standing culture for 5 days at $25^{\circ}C$ with 5% inoculum volume.

• Korean Journal of Food Science and Technology
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• v.16 no.1
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• pp.90-94
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• 1984

We deduced a possible metabolic pathway of L-malate in a malo-alcoholic yeast, Schizosaccharomyces japonicus var. japonicus St-3. The malic enzyme (EC 1.1.1.40) prepared from the microorganism was about four times as active as that of malate dehydrogenase (EC 1.1.1.37). And Km values of malic enzyme and malate dehydrogenase for malate were found to be 3.125 mM and 4.761 mM, respectively, which referred to the fact that the affinity of malic enzyme for the substrate was greater than that of malate dehydrogenase. We also found that pyruvate was produced with disappearing malate in malo-alcoholic fermentation, and that the addition of $Mn^{2+}$ activated malic enzyme activity. Based on these results obtained we have deduced a main pathway of malate${\rightarrow}$pyruvate${\rightarrow}$acetaldehyde${\rightarrow}$ethanol for the utilization of L-malate by this malo-alcoholic yeast strain.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.4
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• pp.621-626
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• 2013

This study compared and analyzed the quality characteristics of five different apple juice concentrates (A~E) after alcoholic fermentation to establish test indicators for their defects. From our results, the titratable acidity was nearly similar in all diluted solutions. However, A and D showed a high pH of above 4.0 while B, C and E exhibited a low pH of below 3.0. In terms of free sugar content, maltose was undetected in A and D. In contrast, about 698 mg% maltose was found in C and more than 1,000 mg% maltose were detected in B and E. Malic acid, one of the main organic acids in apple, was measured at a high value of about 600 mg% in A and D and about 50 mg% in B, C and E. Potassium, one of the main minerals, was about 180 mg% in A and D, whereas a small amount of potassium, ranging between 6~9 mg% were present in B, C and E. Preservative (by sorbic acid) was not detected at all in all apple juice concentrates (A~E). When the above diluted apple concentrates were fermented, the alcohol contents were 11.2% and 10.8% in DAFB and AAFB, respectively. Alcoholic fermentation almost did not take place in BAFB, CAFB and EAFB. The use of maltose as the yeast may have influenced the fermentation. However, B, C and E were thought to be either defective or contaminated apple concentrates based on the analysis results of free sugar and organic acid.

• Korean Journal of Food Science and Technology
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• v.21 no.6
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• pp.832-837
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• 1989

It has been suggested that medium chain fatty acid(MCFA) may be toxic to yeast and bacteria and thus play a role in the inhibition of alcoholic and malolactic fermentations and also important contributors to wine flavour We measured, by the use of GLC, the concentrations of octanoic, decanoic and dodecanoic acids produced by 12 wine yeast strains during the alcoholic fermentation of a grape juice-like medium. In general, there was a high production of MCFA at first, dropping dramatically later. The formation of MCFA is largely dependent on yeast strain but it also depends upon temperature, sugar concentration, stirring and carbon dioxide sparging.

• Food Science and Preservation
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• v.3 no.2
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• pp.171-178
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• 1996

This study was carried out for the purpose of improving the persimmon vinegar. The acetic acid bacteria strain JST-3, using acetic acid fermentation was isolated from the traditional persimmon vinegar. The optimum conditions for high yield of acetic acid were studied in the shaking bath. Acetic acid bacteria was cultured at 3$0^{\circ}C$ for 4 days and transferred to persimmon alcoholic juice for acetic acid fermentation. The optimum initial acidity for acetic acrid fermentation was 1%(w/v) and the addition of glucose or yeast extract was observed to produce relatively low yield of acetic acid. Succinic and acetic acid were major organic acid in the persimmon vinegar, The contents of lactic acid which was known to increase off-flavor were very low. Sensory evaluation revealed that the persimmon vinegar prepared in this study was superior to two commercial ones in the aroma and taste.

• Journal of Nutrition and Health
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• v.13 no.3
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• pp.139-144
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• 1980

A study was conducted to examine the physical and chemical changes of wines fermented from three different varieties by three different methods. The products were evaluated by twenty subjects on color, aroma, and taste. The results were as follows; 1) The moisture contents of those varieties were ranged from 90. 70 to 90.82% The Brix sugar and sugar contents were in order of Muscat Bailey A>Alden>Cambell Early. The titratable acidity was higher in Muscat Bailey A and Alden than in Cambell Early while PH of Cambell Early was higher than those of the two others. 2) The specific gravities of the products were slightly decreased as the fermentation progressed. 3) The yeast-fermentation showed the higher degree of alcoholic contents compared to the natural fermentations. of the natural fermentations, the washed-natural fermentation resulted in the lower alcoholic contents than unwashed one. 4) The PH's were also higher in the yeast-fermentation products than in the natural fermentation groups. The difference, however, was smaller as the fermentation progressed further. 5) The total ester coutents of the yeast fermentation group were slightly higher at the beginning of the fermentation than those of the natural fermentation products and the contents were increased during the fermentation in overall. 6) Twenty panel mentors judged the ripe wine products and the order of preference was Alden>Muscat Baliey A>Cabell Early. They preferred the yeast-fermentation wine to the natural fermentation products.

• Food Science and Biotechnology
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• v.15 no.1
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• pp.112-116
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• 2006

Levels of ethyl carbamate, by-product produced naturally during fermentation, in Korean alcoholic beverages were determined by Gas Chromatography/mass spectrometry/selected ion mode (GC/MS/SIM), and their daily intake by Korean adult group was estimated. In GC/MS/SIM analysis 0.8-10.1, 0.5-0.8, 0.4-0.9, 3.5-689.9, 8.4-30.3, 13.9-30.0, and 1.7-11.7 ppb of ethyl carbamate were detected in soju, beer, takju, fruit wine, cheongju, whiskey, and grape wine, respectively. Maximum daily exposure of ethyl carbamate through alcoholic beverage consumption was 7.41 ng/kg body weight/day for average Korean male, with one soju brand and two fruit wine brands showing high ethyl carbamate level.

• Korean Journal of Microbiology
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• v.8 no.3
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• pp.107-115
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• 1970

In order to brew Takju, Korean flour wine, it requires three necessary steps for specific brewage. One is primary brewing process and another main brewing process to sacharify and perform alcoholic fermentation. After previous two brewing passing, the mash of main brewing process mixed with 1 volume of water is commercial Takju. Three samples were obtained from three breweries and incubated at $28{\pm}1^{\circ}C$for the alcoholic fermentation. All the samples were analyzed for observation of the changes of various biochemical constituents which were contained in the mashes of two brewing processes and in Takju. The starch contents of the suspensions in the primary and main mashes, and in Takju were 28.08, 25.92, 3.83%, and decreased considerably within 36-48 hrs and thereafter slowly. The amounts of water soluble carbohydrates and reducing sugars in three steps had a tendency of decreasing within 48 hours. The initial numbers of yeasts per 1ml in the suspensions were $1.74{\times}10^8$, $1.65{\times}10^8$, $0.66{\times}10^8$, appeared the highest at 72 hours (12.66%) in main process, and in the case of Takju kept increasing untill 60 hours. The dextrin contents in the mashe of primary process through the long period were 0.34 - 0.68%, in the main one were 0.12 - 0.32%, concerning with the amylase activities which were stronger in the mash of the primary process than in that of the main. The contents of methanol and cellulose in the mashes of two processes were 3.40-0.68%, in the main one were 0.12-0.32%, concerning with the amylase activities which were stronger in the mash of the primary process than in that of the main. The contents of methanol and cellulose in the mashes of two processes were 3.40-5.98mg/ml, 0.43-0.48% during the fermentation. The consumption of crude protein the mashes of Takju revealed with time, on the contrary, the production of free amino acids and oligo-peptides were performed, depending upon the affection of proteinase. The amount of tannic acid in Takju was 0.0073-0.0098mg/ml and organic acids of these three groups increased with time and hydrogen ion concentration was 3.28-4.43.

• Food Science and Preservation
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• v.23 no.4
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• pp.591-598
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• 2016

The purpose of this study was to screen desirable yeast strains for alcoholic fermentation of tomato paste without sugar addition. The moisture, crude protein, crude fat, ash, and soluble nitrogen contents of the tomato paste ($25^{\circ}Brix$) were found to be 67.33%, 1.90%, 0.03%, 0.02%, and 30.72%, respectively. Free sugars found in the paste were fructose and glucose. Most abundant free amino acids of the paste were glutamic, aspartic, and ${\gamma}$-aminobutyric acids. Total seven yeast strains (Saccharomyces cerevisiae KDH (TWA), S. cerevisiae Lalvin ICVD-47 (TWB), S. cerevisiae Lalvin RC-212 (TWC), S. cerevisiae Lalvin K1-V1116 (TWD), S. bayanus Lalvin EC-1118 (TWE), S. cerevisiae Enoferm (TWF), and S. cerevisiae DJ97(KCTC8842P) (TWG)) were tasted for alcohol fermentation of the tomato paste. The highest alcohol content (8.2%) and the lowest residual sugar content ($13.25^{\circ}Brix$) were observed in the tomato paste fermented using the S. cerevisiae Lalvin ICVD-47 strain (TWB) after 3 day and 4 day of fermentation, respectively. Sugar and reducing sugar contents, and pH of the tomato paste were not remarkably affected by the difference in yeast strains used, showing $13.25{\sim}13.45^{\circ}Brix$, 28.37~28.48 mg/mL, and 4.43~4.54, respectively, after 4 day of fermentation. Color and total acid content were significantly affected by the types of yeast strains and fermentation time, but the numerical changes were negligible. These results indicate that TWB would be the suitable strain for alcoholic fermentatiom of tomato paste based on its highest alcohol production and the lowest residual sugar content produced during fermentation.