• Korean Journal of Microbiology
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• v.52 no.1
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• pp.98-109
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• 2016

The study was aimed to investigate the mixing ratio of kiwi and persimmon juices for the production of good quality wine by Saccharomyces cerevisiae Y28. Firstly, the optimum condition of rapidase treatment for the kiwi and persimmon juices was established, thereafter various mixing ratio (10:0, 9:1, 8:2, 7:3, 6:4, 5:5) of kiwi and persimmon was investigated regarding physiochemical properties and flavor compounds of wine. As the result, the optimum conditions were obtained as 0.3% rapidase for 1 h in kiwi and 0.3% rapidase for 3 h in persimmon. According to higher ration of persimmon, the pH of wines increased from 3.69 to 3.77, while the acidity of wines decreased from 2.07% to 1.51% at 14 days fermentation. The ranges of brix and reducing sugar in wines were decreased which ranges around 9.6 to 8.8 and 6.07 to 6.90 g/L, respectively, after fermentation. Major organic acid in wines were identified as tartaric acid, malic acid, and citric acid. A small amount of free sugar such as sucrose and glucose were detected in wines, but fructose was completely absent. The soluble phenolic contents were decreased that ranges around 1.00 to 1.25 g/L, in contrast, browning degree were increased ranges around 0.212 to 0.412 after fermentation. The major flavor components were identified as ethyl acetate and hydrazine, and 1,1-dimethyl. Importantly, phenylethyl alcohol was detected from the all wines that have a typical rose like flavor. But sensory test results and preference of kiwi-persimmon (7:3) mixing wine was better than the other wines.

• Applied Biological Chemistry
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• v.18 no.1
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• pp.16-22
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• 1975

This experiment was carried out to investigate the physiological characteristics of two original yeasts, 5-Y-5 and 6-Y-6, which selected from 24 Takju yeasts and three mutants, 30-24,30-81 and 40-27. induced from two original yeasts by the irradiation of UV light. The results were summarized as follows. 1) Alcohol tolerances of three mutants were decreased in some degree as compared with those of original yeasts. 2) Tolerances of lactic and citric acids of acid producing mutant 30-81, was increased than those of original yeasts. 3) In the case of using ammonium sulfate as a nitrogen source, two original yeasts and three mutants required Ca-pantothenate as a essential growth factor and four strains of yeasts except the mutant, 30-81, required biotin as a stimulated growth factor, When asparagine was used as a nitrogen source, two original yeasts and three mutants showed the same as above result but the stimulated effect of biotin was far less. 4) Propagation powers of the mutants were weaken than those of original yeasts, particular that of acid producing mutant, 30-81, was the weakest in the three mutants. 5) The optimum temperature for fermentation of original yeasts were $30^{\circ}C\;to\;35^{\circ}C$ but three mutants were $25^{\circ}C\;to\;30^{\circ}C$. 6) The optimum pH for fermentation of original yeasts were pH 5 to 6, and there is no appreciable difference between original yeasts and three mutants. The fermentation power of mutant,30-81, was decreased more rapidly than those of other mutants according to approach neutral. Three mutants were more sensible to heat than original yeasts. 7) Two original yeasts and three mutants were inhibited more over 20 percent of sugar for fermentation and three mutants were more sensible to sugar concentration than original yeasts.

• Journal of Life Science
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• v.21 no.4
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• pp.509-514
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• 2011

Maloactic fermentation (MLF) occurs after completion of alcoholic fermentation and is mediated by lactic acid bacteria (LAB), mainly Oenococcus oeni. Kiwi wine more than commercial grape wine has the problem of high acidity. Therefore, we investigated the optimal MLF conditions for regulating strong acidity and improving the quality properties of wine fermented with Kiwi fruit cultivated in Korea. For alcohol fermentation, industrial wine yeast Saccharomyces cerevisiae KCCM 12650 strains and LAB, known as MLF strains, were used to alleviate wine acidity. First, the various experimental conditions of Kiwi fruit, initial pH (2.5, 3.5, 4.5), fermenting temperature (20, 25, $30^{\circ}C$), and sugar contents (24 $^{\circ}Brix$), were adjusted, and after the fermentation period, we measured the acidity, pH, and the change in organic acid content by the AOAC method and HPLC analysis. The alcohol content of fermented Kiwi wine was 12.75%. Further, total acidity and pH of Kiwi wine were 0.78% and 3.5, respectively. Total sugar and total polyphenol contents of Kiwi wine were 38.72 mg/ml and 60.18 mg/ml, respectively. With regard to organic acid content, the control contained 0.63 mg/ml of oxalic acid, 2.99 mg/ml of malic acid, and 0.71 mg/ml of lactic acid, whereas MLF wine contained 0.69 mg/ml of oxalic acid, 0.06 mg/ml of malic acid, and 3.12 mg/ml of lactic acid. Kiwi wine had lower malic acid values and total acidity than control after MLF processing. In MLF, the optimum initial pH value and fermentation temperature were 3.5 and $25^{\circ}C$, respectively. Therefore, these studies suggest that establishment of optimal MLF conditions could improve the properties of Kiwi wine manufactured in Korea.

• Applied Biological Chemistry
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• v.47 no.1
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• pp.78-84
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• 2004

In order Nuruk to improve the quality of millet wine, a traditional Jeju cereal wine, yeasts and molds were isolated from 35 kinds of Nuruk collected nationwide. Isolated strains were screened for saccharification of starch and brewing of millet wine. Fermentation characteristics of millet wine with different types of Nuruk were also investigated. The average number of microbial populations in the Nuruk were $6.4{\times}10^5{\sim}4.5{\times}10^7\;cfu/g$ for molds and $1.4{\times}10^4{\sim}7.7{\times}10^7\;cfu/g$ for yeasts. Among the 169 strains of molds and 103 strains of yeasts, 16 strains were screened for saccharifying activity on starch as a substrate, and one yeast strain was screened for the brewing of millet wine. A8-3, supposed as Aspergillus sp., showed the highest enzyme activities of glucdamylase, ${\alpha}-amylase$ and xylanase while B23-3 strain, supposed as Rhizopus sp., showed the highest saccharifying activity. A10-4, supposed as Saccharomyces sp., showed the highest level of weight loss from $CO_2$ evolution, sugar and alcohol tolerance during fermentation. When the Nuruk was made after inoculation with the selected strains, saccharifying activity was higher for the co-cultivation of A8-3 and B23-3 than individual cultivation of each strain. Similar saccharifying activities were shown in both disc-type and pellet-type Nuruk. It was suggested that pellet-type Nuruk could improve fermentation yield. The collected Nuruk consisted of $10{\sim}13%$ moisture, $55{\sim}70%$ total sugar, $10{\sim}18%$ crude protein, $0.2{\sim}1.0%$ crude fat and $1.8{\sim}2.1%$ ash. The Nuruk made in this study was composed of $12{\sim}15%$ moisture, $61{\sim}71%$ total sugar, $15{\sim}20%$ crude protein, $0.4{\sim}1.5%$ crude fat and $1.1{\sim}1.5%$ ash.

• The Korean Journal of Food And Nutrition
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• v.30 no.2
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• pp.305-311
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• 2017

This study aimed to evaluate the fermentation characteristics of mixed Makgeolli with barley and wheats under, fermentation at different temperatures (20, 25, and $30^{\circ}C$) and time (3, 6, and 9 days). The pH and sugar of mixed Makgeolli were 3.68~4.26 and $12.30{\sim}17.31^{\circ}Brix$, respectively. The total acidity showed proportionate increase with fermentation temperature and time; whereas, reducing sugar contents decreased with increasing fermentation temperature and time. The alcohol contents of mixed Makgeolli varied significantly by fermentation temperature and time (p<0.05). In terms of color values, the L value decreased with increasing fermentation temperatures, and a value increased significantly with increasing fermentation time. The number of microorganisms (yeast, total bacteria and lactic acid bacteria) in mixed Makgeolli decreased progressively with increasing fermentation temperature and time. Among the organic acids (citric, lactic, malic, and pyruvic acids) in mixed Makgeolli, citric and lactic acid was present at the highest concentrations. From these results, the optimum fermentation conditions of mixed Makgeolli with barley and wheat were $20{\sim}25^{\circ}C$ for 6 days.

• Food Science and Preservation
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• v.13 no.3
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• pp.329-336
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• 2006

The characteristics of mash qualities of takju prepared by addition of chestnut peel powder(5%, 10%, 20% and 30% per steamed rice) were investigated during fermentation. That is, in all fermentation periods, changes of pit total acid, organic acids, solids, amino nitrogen, total sugar and reducing sugar, microorganisms, alcohol and color were determined and analyzed. There was significant differences in characteristics of mash qualities by addition of chestnut peel powder. In general, contents of total acid, organic acids, amino nitrogen, total sugar, reducing sugar and ethanol of takju added with chestnut peel powder were lower than those of steamed rice only, whereas solid contents was higher. But ethanol content of takju added with 5% of chestnut peel powder after 8 days of fermentation was 9.6% which was similar to that of takju prepared by addition of steamed lice only. Also, microbial populations such as total viable cells, yeast and lactic acid bacteria of the treatments were increased to about $10^8CFU/mL$ after 2 days of fermentation and then decreased gradually. In the beginning stage of fermentation color differences value of the treatments were $1.99{\sim}10.27$, and the differentials reduced gradually during fermentation.

• The Korean Journal of Food And Nutrition
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• v.29 no.4
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• pp.565-572
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• 2016

This study was conducted to evaluate the quality of barley (Huinchalssalbori) and domestic wheats (Keumkangmil, Baegjoongmil, Jogyeongmil). The pH and total acidity of mixed Makgeolli were 4.04~4.12% and 0.94~1.06%, respectively. The total acidity, sugar and alcohol contents of Makgeolli, but not pH, varied significantly by wheat cultivar (p<0.05). In terms of color values, the L-value of Baegjoongmil, a-value and b-value of Keumkangmil were highest. The reducing sugar contents was approximately 5.65~7.85 mg/mL, and those of Jogyeongmil and imported wheat were approximately 5.70 mg/mL lower. The yeast cell numbers did not differ significantly, with the exception of in the rice Makgeolli (p<0.05). Among the organic acids (citric, malic, pyruvic and lactic acids) in Makgeolli, citric acid was present at the highest concentration. Regarding the sensory characteristics of Makgeolli mixed with barley and wheat, taste and overall acceptability were highest in Baegjoongmil, and appearance and flavor were highest in Keumkangmil. The rice Makgeolli showed the lowest sensory values, with the exception of appearance. The results of this study suggest that mixing Makgeolli with barley and wheat is an expected to replace the wheat materials in the domestic wheat to be imported.

• Applied Biological Chemistry
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• v.46 no.3
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• pp.201-206
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• 2003

An apple wine was prepared by fermentation at $25^{\circ}C$ for 2 weeks using Saccha개myces cerevisiae KCCM 12224, followed by aging at $15^{\circ}C$ for 14 weeks, and its physicochemical and microbiological changes were investigated. The viable bacterial cell numbers, increased from $1.4{\times}10^3\;CFU/ml$ at the beginning of fermentation, to $2.8{\times}10^6\;CFU/ml$ after 2 weeks, but decreased to $1.0{\times}10^5\;CFU/ml$ after aging. The viable yeast cell numbers changed from $4.3{\times}10^4\;CFU/ml$ to $1.2{\times}10^7\;CFU/ml$ during the fermentation, and decreased to $1.2{\times}10^4\;CFU/ml$ after aging. Sugar content changed from $20.0^{\circ}Brix$ to $8.5{\circ}Brix$, and reducing sugar content was changed from 9.66% to 6.44%. Alcohol content and acidity increased to 7.0% and from 0.19% to 0.24%, respectively. No changes in acidity, pH, and sugar content were observed during the aging, but reducing sugar and solid contents decreased. When apple wine was fultered through $0.45\;{\mu}m$ nitrocellulose membrane followed by various ultrafiltration membranes with different molecular weight cut-off values, the initial flux $(121.2\;liter/m^2/h)$ and the average flux of Biomax 100k membrane were the highest among the membranes used. These membrane filtration treatments resulted in complete removal of microorganisms as well as decrease in turbidity and solid content without changes in other chemical properties. No changes in the physicochemical properties of the apple wine and no microorganisms were detected during the storage at $156{\circ}C$ for 6 weeks.

• Korean Journal of Microbiology
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• v.50 no.4
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• pp.351-359
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• 2014

A beverage was produced by the fermentation of mixed extracts from the various fruits, vegetables, algae, and medical herbs. The physicochemical properties of the fermented beverage of plant extracts (FBPE) and microbial diversity were analyzed in cultures enriched from FBPE using 16S and 26S rRNA gene sequence analyses. The pH, acidity, $^{\circ}brix$, reducing sugar, and alcohol contents of the FBPE were determined to be the 3.48, 1.68%, 70.0, 1,026 g/L, and 3.5%, respectively. The most abundant free sugar and organic acid in the FBPE were glucose (567.83 g/L) and tartaric acid (93.68 mg/L), respectively. Lactobacillus homohiochii was the predominant species in all enriched culture samples: 100% of the species in 0B (0% sugar) and 40B (40% sugar) libraries and 95.6% of 20B library (20% sugar). Lactobacillus fructivorans was detected in the 20B library. The predominant species in the samples of enrichment cultures collected from FBPE with three different sugar concentrations were: Candida zeylanoides (45.2%) in the 0Y library (0% sugar), Candida lactis-condensi (35.7%) and C. zeylanoides (35.7%) in the 20Y library (20% sugar), and C. lactis-condensi (38.1%) in the 40Y library (40% sugar). This result may provide a useful frame of reference for further analyses of microbial population dynamics in FBPE.