• KSBB Journal
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• v.24 no.5
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• pp.446-452
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• 2009

Oleyl alcohol, butyl butyrate, and two different ionic liquids were evaluated for the extraction of butanol from culture broth without toxic effect to cells. The tested solvents showed more than 50% extraction efficiency, and oleyl alcohol was chosen as the best extractant for butanol among the used extractants with a partition coefficient of 2.89. When oleyl alcohol was used as an extractant, more than 80% of butanol was extracted in the wide range of butanol concentrations (1-20 g/L) and pH values (pH 4-5.5). In extractive fermentation using oleyl alcohol only, there was 11% more butanol production and glucose consumption when compared to that without extractive fermentation, implicating a reduced inhibitory effect of butanol due to butanol removal to the oleyl alcohol phase. In addition, oleyl alcohol did not inhibit cell growth, while a mixture of oleyl alcohol and butyl butyrate with the volume ratio of 9:1~7:3 inhibited either butanol production or cell growth significantly due to the toxicity of butyl butyrate to cells. In conclusion, oleyl alcohol can be used as an efficient and non-toxic solvent for extractive fermentation for butanol production.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.11
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• pp.1425-1430
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• 2007

This study investigated alcohol and acetic acid fermentation conditions for the quality control of pomegranate vinegar In the alcohol fermentation process, alcohol content was the highest at a pomegranate juice concentration of $16^{\circ}Brix$, but suitable to fruit vinegar standards at a concentration of $12^{\circ}Brix$. In the concentrated pomegranate juice alcohol fermentation free sugars, fructose and glucose were detected at the beginning of fermentation; at day 4 of fermentation only glucose was detected and decreased as time passed. Organic acids were also detected, including oxalic, lactic, acetic, and citric acid, and they did not change greatly during the alcohol fermentation process. In the acetic acid fermentation process, total acidity increased from 1.56% to 5.54%, where acetic acid increased; however, oxalic, lactic, and citric acids changed only slightly. In conclusion, pomegranate vinegar can undergo alcohol and acetic acid fermentation processes using concentrated pomegranate juice of $12^{\circ}Brix$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.8
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• pp.1236-1241
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• 2010

The present study investigated the alcohol fermentation characteristics of citrus fruit hydrolysates for the development of citrus fruit wine with enhanced functionality. The alcohol content of whole citrus (A) and removed peels citrus fruit (B) was 10.13% and 10.83%, respectively. The sugar content of (A) was $12.98^{\circ}Brix$, which was slightly higher than that of (B) ($11.38^{\circ}Brix$), but no significant difference in the alcohol fermentation characteristics was observed. Although the hesperidin content was not largely affected by removed peels the narirutin content of (A) was increased to $281.31\;{\mu}M$, which was significantly higher than that of (B) ($199.05\;{\mu}M$). Thus, the whole citrus was used for fermentation. Investigation of alcohol fermentation characteristics based on yeast type found that the maximum alcohol content was 12.75% when S. bayanus EC-1118 was used. The alcohol content reached 12.40% at an initial acidity of 0.2%, but when the initial acidity was higher than 0.2%, the alcohol content was slightly decreased. At an initial sugar content of $22^{\circ}Brix$, the alcohol content was 11.65%, and the maximum alcohol content of 12.85% was observed when at an initial sugar content of $24^{\circ}$Brix.

• Applied Biological Chemistry
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• v.45 no.2
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• pp.66-70
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• 2002

In this study, three kinds of Saccharomyces cerevisiae strains (KCTC 7106, 7238, 7904) were tested with respect to the ability of alcohol fermentation at $20^{\circ}C$ for 3 weeks, and S. cerevisiae KCTC 7106 was the most effective strain in alcohol fermentation with sweet persimmon. To increase the utility of sweet persimmon, the fruits stored for 1 year were used to make an alcohol beverage. It was adjusted 25% of total sugar content and allowed alcohol fermentation with shaking at 120 rpm and $30^{\circ}C$. The alcohol content of 11.6% showed at 15 days and it did not change until 25 days. The initial pH of the fermentation was near 5 then decreased to 4 within 5 days and the initial vitamin C content, 5.04 ${\mu}g/ml$, gradually decreased with fermentation periods. In the other study, the alcohol fermentation from fresh harvested persimmons showed 13% alcohol content at $20^{\circ}C$ for 30 days without agitation, while the alcohol content of the fermentation at $30^{\circ}C$ was 11.8% at 25 days and 13.4% at 35 days.

• Microbiology and Biotechnology Letters
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• v.16 no.3
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• pp.231-237
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• 1988

Several methods to produce ethanol from tapioca starch were examined. Among four methods tested, alcohol fermentation with extruded tapioca starch was the most effective, which alcohol yield was 460.5 f/ton. After 69hours reaction with Rhizopus sp. glucoamylase, 108.7mg/$m\ell$ of reducing sugar were produced from extruded tapioca and 43.8mg/$m\ell$ from raw tapioca starch. In alcohol fermentation with extruded tapioca, the high concentration of alcohol at early stage prevented bacterial contamination and the fermentation rate was increased due to the high saccharifying power of glucoamylase on the extruded starch, but extrusion temperature had no influence on the fermentability, Scanning electron microscopy showed that the extrusion process changed the structure of tapioca starch granule to more susceptible form to glucoamylase attack than the raw starch. And glucoamylase of Rhizopus sp. had stronger digestion activity on both extruded tapioca and raw tapioca starch than that of Aspergillus usamii.

• Korean Journal of Food Science and Technology
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• v.36 no.1
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• pp.92-96
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• 2004

Chitin and its derivatives (chitosan and glucosamine) were studied for their effects on ethanol production using YPD (yeast extract 10%, peptone 20%, glucose 20%, agar 20%) medium. All chitin derivatives, particularly chitin, increased ethanol production compared with control. In non-steamed alcohol fermentation of tapioca, addition of 0.9% chitin yielded higher ethanol production (13.6%) with lower acetaldehyde (21.91 ppm) and methanol (65.49 ppm) contents than those (12.7%, 35.05 ppm, 84.31 ppm, respectively) of control after fermentation for 120 hr at $30^{\circ}C$. Results indicate that chitin can be used to increase ethanol production in non-steamed alcohol fermentation of tapioca.

• Journal of the East Asian Society of Dietary Life
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• v.18 no.1
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• pp.41-48
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• 2008

This study focused on the alcohol fermentability of traditional Nuruk, as well as yeast containing traditional Nuruk, in the production of Yakju. The fermentation performed with 30% Nuruk was effective with regard to alcohol yield. In addition, the fermentation containing 70% Nuruk showed the highest titratable acidity due to increased amounts of organic acids (succinic acid, oxalic acid, malic acid, acetic acid), which, however, negatively influenced the Yakju quality. Moreover, microbiological contamination always occurred in the fermentations using only Nuruk. In contrast, in the experiments with the yeast containing Nuruk, higher alcohol content and lower titrable acidity were obtained, independent of the Nuruk ratio used, positively effected the Yakju taste and flavor. Overall, the fermentation performed using the yeast containing 30% traditional Nuruk showed the best results for Yakju production.

• Microbiology and Biotechnology Letters
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• v.19 no.5
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• pp.487-490
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• 1991

In this study continuous alcohol fermentation of molasses by the recirculation system has investigated. After cultivation of yeast cells in the YPD medium with increasing the medium concentration from 10 to 183.5 g/l stepwisely, the fermentation medium was replaced by molasses. The maximum cell mass was 25 g/l, and the mean cell mass during the operation was 23.5g/1, which was 3.4 times higher compared with a conventional batch system. The optimum fermentation conditions with feeding molasses of 180 g/l were obtained when the fermentation was carried out at 500 rpm and at the dilution rate of 0.037 $h^{-1}$. Under these conditions we could safely operate the fermentor for 645 h without any trouble. The maximum alcohol productivity was 4.9 g$l\cdot h$ with an alcohol concentration of 53.9 g/l at the dilution rate of 0.091$h^{-1}$.

• Journal of Biosystems Engineering
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• v.43 no.3
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• pp.229-236
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• 2018

Purpose: Makgeolli is a traditional alcoholic beverage made from rice with a fermentation starter called "nuruk." The concentration of alcohol in makgeolli depends on the temperature of the fermentation tank. It is important to monitor the alcohol concentration to manage the makgeolli production process. Methods: Data were collected from 84 makgeolli fermentation tanks over a year period. Independent variables included the temperatures of the tanks and the room where the tanks were located, as well as the quantity, acidity, and water concentration of the source. Software for the multilayer perceptron model (MLP) was written in Python using the Scikit-learn library. Results: Many models were created for which the optimization converged within 100 iterations, and their coefficients of determination $R^2$ were considerably high. The coefficient of determination $R^2$ of the best model with the training set and the test set were 0.94 and 0.93, respectively. The fact that the difference between them was very small indicated that the model was not overfitted. The maximum and minimum error was approximately 2% and the total MSE was 0.078%. Conclusions: The MLP model could help predict the alcohol concentration and to control the production process of makgeolli. In future research, the optimization of the production process will be studied based on the model.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.4
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• pp.760-765
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• 1999

Changes in physiochemical properties of Sunchang sikhe kochujang, the most famous traditional kochujang, by red ginseng addition(1, 2 and 5% red ginseng on the total weight basis) were investigated. Measurements of physiochemical parameters such as reducing sugar content, alcohol content, amino type nitrogen content and color difference value were conducted during fermentation at 25oC for 120 days. Alcohol content was increased from the begining of fermentation, reaching at the highest level after 90 days of fermentation and then slowly reduced. Alcohol content of red ginseng kochujang was generally higher than that of control kochujang after 90 days of fermentation. Crude protein content of control kochujang and red ginseng kochujang were reduced during fermentation whereas amino type nitrogen content were gradually increased during fermentation. Amino type nitrogen content of red ginseng kochujang appeared to be slightly lower than that of the control kochujang. The reduction in amino type nitrogen content of red ginseng kochujang was negatively related to the level of red ginseng addition. Among color difference values, L and b value of both control kochujang and red ginseng kochujang were reduced by 30 days from the begining of fermentation and then started to be increased.