• Korean Journal of Food Science and Technology
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• v.46 no.1
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• pp.25-32
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• 2014

This study aimed to analyze the general ingredients and volatile compounds of ipguk (koji) and nuruk soju distilled under reduced pressure (RP) or atmospheric pressure (AP) conditions. After the secondary brewing process, soju made using ipguk had a final fermentation alcohol content of $18.0{\pm}0.6%$, whereas soju made using nuruk reached $14.3{\pm}1.7%$. The level of succinic acid was the highest in ipguk soju ($7,685.33{\pm}34.97$ ppm), but nuruk soju also showed a high level of succinic acid ($5,945.79{\pm}76.30$ ppm) after its final fermentation. In an analysis of fusel alcohol content, the level of n-propanol in ipguk soju (389.10-397.27 ppm) was similar under different RP (50 cm Hg and 60 cm Hg) and AP conditions ($80^{\circ}C$ and $90^{\circ}C$). Under RP and AP conditions, the isoamyl alcohol/isobutanol (A/B) ratio was similar, ranging from 1.32-1.35. In ipguk soju distilled under RP conditions of 50 cm Hg and 60 cm Hg, the amount of the toxic component, acetaldehyde, was 8.59 and 9.27 ppm, respectively. Under AP conditions, the amount of acetaldehyde in ipguk soju distilled at 80 and $90^{\circ}C$ was 9.80 and 10.63 ppm, respectively, indicating that the amount of acetaldehyde did not differ depending on the distilling method used. These results suggest that the liquor distilled from the mash produced using ipguk under RP conditions may be of a higher quality.

• Korean Journal of Food Science and Technology
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• v.49 no.3
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• pp.279-285
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• 2017

This study reviews the manufacturing characteristics of distilled liquor prepared using Saccharomyces cerevisiae 88-4 separated from traditional Nuruk. From analysis of soju mash (sool-dut) during the fermentation process, 17.2% of alcohol was detected in the final fermentation with succinic acid present at the highest level ($7,164.3{\pm}85.2ppm$). From the analysis of alcohol content in different distillation conditions, distillation condition No. 6 showed the lowest amount of alcohol ($29.6{\pm}0.0%$), whereas distillation condition No. 4 showed the highest amount ($59.9{\pm}0.1%$). N-propanol has been detected at the highest level in distilled liquor under conditions No. 1 and 4, each being $163.4{\pm}18.3$ and $174.0{\pm} 0.1ppm$, respectively. Isobutanol showed a tendency similar to n-propanol. Distilled liquor in conditions No. 1 and 4 has shown the highest acetaldehyde level, each being $303.4{\pm}4.5$ and $325.4{\pm}13.1ppm$, respectively. After distillation, 14 volatile substances were found in common, with isoamyl alcohol present at the highest levels in all the distilled liquors. Distillation conditions No. 3, 5, 6, and 7 have shown high levels of isobutanol that emits a banana-like fragrance and ethyl octanoate that emits a pleasant fruity and floral fragrance.

• Food Science and Preservation
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• v.22 no.5
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• pp.674-682
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• 2015

In this study, vinegar was produced using urushiol-free fermented Rhus verniciflua extract to create a lacquer with added value. The effect of manufacturing conditions on the quality of vinegar using detoxified R. verniciflua extract for fermentation was investigated. The acidity of the vinegar for inoculations with various liquid starter contents was 4.8~4.9%, and it was similar among all treatment groups. The acidity of vinegar was higher when the initial alcohol content was high. The acetic acid yields were 82.8%, 84.4%, 77.7%, and 69.5%, and the maximum yield was observed when the initial alcohol content was 6%. For acetic acid fermentation using different amounts of detoxified R. verniciflua extracts, the acidity of the vinegar with the extract after fermentation was 5.3~5.9%. However, the acidity of vinegar without the extract was 5.5%. The intensity of the brown color was high for vinegar without the extract. Hunter's L values were high for vinegar with an extract content of 2%. Acetic acid (53.3~65.8 mg/mL) was the predominant acid. Arginine ($190.3{\sim}333.3{\mu}g/mL$), proline ($125.6{\sim}290.8{\mu}g/mL$), alanine ($126.1{\sim}270.9{\mu}g/mL$), and glutamic acid ($159.0{\sim}262.4{\mu}g/mL$) were the predominant amino acids in detoxified R. verniciflua vinegar.

• Journal of the East Asian Society of Dietary Life
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• v.22 no.1
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• pp.41-51
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• 2012

We produced Hwanggiju (added 0.5~2.0% of ground Astragali Radix compared to starch contents) and investigated the physicochemical characteristics, DPPH free radical scavenging activities, polyphenol contents, and sensory evaluation. For all treatments, the initial pH was 3.9~4.1 and gradually decreased for 6 days from the 1st mashing day, and then rapidly increased to 4.67. As the fermentation proceeded, total acid contents increased in most of the treatments, reduced temporarily after the 2nd mashing time because of the addition of starch material and water, and then slightly rose again. There were little changes in pH and total acid contents followed by adding ground Astragali Radix (AR) to the fermentation periods. Amino acidities of all treatments showed patterns of which consistently rose as the fermentation proceeded and slightly reduced followed by increasing the addition rate of ground AR to the mashes. Soluble solid and alcohol contents also increased continuously and there were few differences among the treatments followed by adding to the ground AR rate. In color, there was no differences in L value, but a and b value showed significant differences by adding ground AR rate. In DPPH free radical scavenging activities, the control (no AR added) showed 53.6% and when grinded AR added, there were improving effects of the activities (0.52~6.9%). In polyphenol contents, the control was 1.05 mg/mL and the ground AR added treatments increased slightly. In the sensory evaluation, the control received a relatively high score ($5.0{\pm}1.0$), and the treatments which added 0.5% ground AR during the 2nd mashing time were also well received ($4.5{\pm}1.3$).

• Journal of the East Asian Society of Dietary Life
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• v.26 no.6
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• pp.543-549
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• 2016

The objective of this study was to investigate quality properties of 'Cheonghyang' wine using different commercial yeast strains. Soluble solid content, pH level and total acidity of 'Cheonghyang' grape were $20^{\circ}Bx$, pH 3.5 and 0.66%, respectively. Total acidity ranged from 0.91~1.06% in the middle stage of fermentation and decreased to 0.77~0.82% when alcoholic fermentation finished. Alcohol content in wines ranged from 12.5% to 12.9% showing no significant difference in yeast strains. Wine fermented with Red Fruit had high volatile acid content (189.0 mg/L) whereas wine fermented with Fermivin indicated low volatile acid content (77.7 mg/L). Wines made with Montrachet, Fermivin and Aroma White had low brightness (L-value) compared to others. Results from sensory evaluation demonstrated that commercial wine yeasts, Montrachet and Fermivin, can be applied to improve sensory properties of 'Cheonghyang' wine such as aroma, acidity and transperency. On the other hand, preferences of wine fermented with EC-1118 strain containing lots of tannins and total polyphenols were significantly reduced.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.12
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• pp.6290-6295
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• 2013

This study examined the fermentative characteristics of red ginseng wine prepared with enzymatically hydrolyzed red ginseng marc (ERGM), which was produced by the polysaccharide hydrolyase and protease treatments of red ginseng marc (RGM). After adjusting the initial soluble solid contents of ERGM broth to $20^{\circ}Brix$ and $30^{\circ}Brix$ with sucrose, respectively, alcohol fermentation was carried out at $25^{\circ}C$ for 9 days. The soluble solid contents decreased from $20^{\circ}Brix$ to $7^{\circ}Brix$ and from $30^{\circ}Brix$ to $13^{\circ}Brix$, and the reducing sugar content decreased to 18 and 24 g/L at 9 days of fermentation, respectively. The ethanol contents increased to 65 g/L and 106 g/L, respectively. The crude saponin content in the ERGM broth was 2~3 times as high as that in the RGM broth after 7 days fermentation. These results show that ERGM is suitable as a raw material for the production of red ginseng wine.

• Food Science and Preservation
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• v.18 no.5
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• pp.811-816
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• 2011

Cryoextraction (a freeze concentration using an instrument) can increase the sugar concentration in grape juice by reducing its water content, similar to the natural freezing of grapes for natural ice wine. In this study, fermentation of freeze-concentrated Campbell Early grape (Vitis labruscana) juice to 36 $^{\circ}Bx$ was carried out using Saccharomyces cerevisiae strains D8 and S13 isolated from Korean grapes. During the fermentation, strains S13 and D8 showed rapid sugar reduction and alcohol production compared with S. cerevisiae Fermivin$^{(R)}$ used as a control. After nine-day fermentation, the residual sugar contents were lower in W13(9.77%) and D8 wine(9.07) than that in Fermivin$^{(R)}$ wine(14.0%). Total acid content was high in the D8>S13>Fermivin$^{(R)}$ wine, in that order. The acetaldehyde content was highest in the D8 wine and lowest in the Fermivin$^{(R)}$ wine, among the three. The methanol content was slightly higher in the S13 and D8 wines than in the Fermivin$^{(R)}$ wine. In the sensory evaluation, the S13 wine exhibited the highest score in flavor and taste among the three wines. Both the two S13 and D8 wines exhibited higher scores than Fermivin$^{(R)}$ wine in overall preference.

• 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.

• Journal of the Korean Applied Science and Technology
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• v.32 no.4
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• pp.758-766
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• 2015

Dextran is a generic term for a bacterial exopolysaccharide synthesized from sucrose and composed of chains of D-glucose units connected by ${\alpha}$-1,6-linkages by using dextransucrases. Dextran could be used as vicosifying, stabilizing, emulsifying, gelling, bulking, dietary fiber, prebiotics, and water holding agents. We isolated new strain capable of producing dextran from Korean traditional kimchi and identified as Leuconostoc sp. strain JYY4. Batch fermentation was conducted in bioreactor with a working volume of 3 L. The media was MMY and 15% (w/v) sucrose. Mineral medium consisted of $3.0g\;KH_2PO_4$, $0.01g\;FeSO_4$, $H_2O$, $0.01g\;MnSO_4$, $4H_2O$, $0.2g\;MgSO_4\;7H_2O$, 0.01 g NaCl, $0.05g\;CaCl_2$ per 1 liter deionized water. The pH of media was initially adjusted to 6.0. The inoculation rate was 1.0% (v/v) of the working volume. Temperature was maintained at $28^{\circ}C$. The agitation rate was 100 rpm. The production pattern of dextran was associated with the cell growth. After 24 hr dextran reached its highest concentration of 59.4 g/L. The sucrose was consumed completely after 40 hr. Growth reached stationery phase when sucrose became limiting, regardless of the presence of fructose or mannitol. When the specific growth rate was 0.54 hr-1, utilization averaged 5.8 g/L-hr. The yield and productivity of dextran were 80% and 2.0 g/L-hr, respectively. Dextrans produced by were separated to two different size by an alcohol fraction method. The size of high molecular weight dextran (45% alcohol, v/v), less soluble dextran, was between MW 500,000 and 2,000,000. Soluble dextran (55% alcohol, v/v) was between 70,000 and 150,000. The molecular weight average of total dextran (70% alcohol, v/v) was between 150,000 to 500,000. The enzymatic hydrolyzates of total dextran of ATCC 13146 showed branched dextrans by Penicillium dextranase contained of glucose, isomaltose, isomaltotriose, and isomaltooligosaccharides greater than DP4 (degree of polymerization) that had branch points. Compounds greater than DP4 were branched isomaltooligosaacharides. Hydrolysates by the Lipomyces dextranase produced the same composition of oligosaccharides as those by Penicillin dextranase.

• Food Science and Preservation
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• v.8 no.3
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• pp.326-330
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• 2001

The characteristics of used wine yeast strains were as follows, S6U showed low fermentation speed than those of other yeast strains, but this strain fermented completely later. The wine fermented by W-3 was very low contents of total acid, 0.75% and the ones fermented by UCD530 and AC- contained much extract, 3.26 mg/L and 3.22 mg/L respectively. The wine fermented by CEG and CS2 were predominant in yellowness, and EC1118 produced large amount of acetaldehyde, 49.9 mg/L than those of other strains. EC1118 and CY3079 displayed low methylene blue dyeing ratio, below 15%, meaning high alcohol tolerance yeast. UCD530 produced extremely high contents of glycerol, succinate and lactate compared with other strains. These properties revealed that UCD530 was a typical Saccharomyces bayanus species. The main organic acids produced by wine yeasts were pyruvate, lactate, succinate and acetate. The concentration of acetate in experimental wine could be divided into two parts, one group had concentration below 170 mg/L (UCD530, EC1118, AC-, CY3079, W-3), and the other had concentration up to 350 mg/L (S6U, CEG, CS2).