• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.2
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• pp.281-286
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• 2014

This study was carried out to develop Yakju, a new kind of Korean traditional rice wine added with bamboo ethanol extract and characterized by containing various health benefits. The wine with bamboo ethanol extract was fermented by adding ginger and pear to improve flavor and quality. Several quality characteristics and physiological functionalities of Yakju were investigated. When bamboo ethanol extract was added to Yakju, the pH level decreased compared to that of the control. However, total acidity and soluble solid levels were higher than those of the control. The alcohol content of Yakju added with bamboo ethanol extract was slightly higher than that of the control. In examining the colors of Yakju containing bamboo ethanol extract, L value was lower than that of the control, whereas b value and brownness were higher. Various organic acids such as citric acid, malic acid, succinic acid, lactic acid, and acetic acid were determined, and the main organic acid among them was lactic acid. Various free sugars such as sorbitol, glucose, and fructose were detected and glucose was the most abundant. Total polyphenol content of Yakju added with bamboo ethanol extract was lower than that of the control. Further, electron-donating ability ranged from 23.8~40.0%, which was higher than that of the control. Nitrite scavenging ability of Yakju added with bamboo ethanol extract ranged from 15.2~36.4%, which was higher than that of the control at pH 6.0. Sensory evaluation of Yakju showed that bamboo ethanol extract+ginger as well as bamboo ethanol extract+ginger+pear treatment significantly increased flavor, taste, and overall acceptance compared to the others.

• Culinary science and hospitality research
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• v.21 no.6
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• pp.103-119
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• 2015

This study was carried out to evaluate the quality of characteristics of Takju, Yakju, and spirit made from Bunkuk(flour), Phellinus linteus and Ginger kuk. The sacharogenic power of Nuruks and pH, brix, acidity, cell numbers of yeast, and alcohol content of Deotsuls were analysed; flavors, organic acids, and sensory evaluation of Takju, Yakju, and spirit were employed in the analysis of this current study. Results showed that the saccharogenic power of Phellinus linteus kuk after fermentation of Nuruks showed the highest level, and Phellinus linteus kuk and Ginger kuk showed the same level after dry Nuruks. During fermentation of Deotsuls, pH and brix decreased with increased fermentation time, while acidity increased with increased fermentation time. Cell numbers of yeast were found to be at the highest level in Phellinus linteus kuk on the first day of fermentation, and it was the same result in the final stage(p<0.05). Alcohol content increased with an increase in fermentation time, and showed no significant difference between control and test in the final stage of fermentation. In terms of analysis of flavor components, acetone and n-amyl alcohol were not detected in Takju, Yakju, and spirit. n-butanol was detected at the highest value, followed by i-amyl alcohol. Fusel oil was detected at the highest level in spirit fermented by Bunkuk. In analysis of organic acids, lactic acid showed the highest content followed by acetic acid. Very small amounts of acetic acid were detected in the spirit and other organic acids were not detected. In sensory evaluation, Takju, Yakju, and spirit made from Phellinus linteus kuk showed the highest score. As a result of this study, Phellinus linteus kuk presented the most desirable Nuruk in order to make Takju, Yakju, and spirit.

• Journal of Food Hygiene and Safety
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• v.26 no.1
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• pp.64-69
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• 2011

Steamed rice is usually used as an essential ingredient when Takju or Yakju is brewed in Korea. Alternatively, non-steamed rice can be used to keep thermolabile nutrients and fresh tastes richer in Takju or Yakju. In this study, therefore, the physicochemical properties (ethanol and sugar contents, pH, total acidities, and turbidities) and the fermentative microbial profiles (aerobic mesophillic bacteria (AMB), fungi, lactic acid bacteria (LAB), acetic acid bacteria (AAB), and Escherichia coli and coliforms) have been compared among 4 Takju and 1 Yakju samples brewed using steamed or non-steamed rice. Yakju brewed using non-steamed rice has approximately 2-3 times higher ethanol and sugar contents than other 4 Takjus brewed using steamed or non-steamed rice. The pH and total acidity values of all the 5 samples ranged 3.77-4.30 and 0.12-0.35, respectively. As for turbidities, Yakju brewed using nons-teamed rice was transparent, but other 4 Takjus were not. The AMB and fungal counts for Yakju brewed using nons-teamed rice were approximately $10^4$-fold less than those for 4 Takjus. The LAB counts for Takju and Yakju brewed using non-steamed rice were $10^3$-fold less than those for Takjus brewed using steamed rice. The AAB counts ranged $2-6\;log_{10}\;CFU/mL$ for all the 5 samples. E.coli and coliforms were not detected. Overall, there was no significant difference in microbial counts among 4 Takjus brewed using steamed or non-steamed rice, but Takju has higher microbial counts than Yakju. All the 5 samples were conclusively considered to be hygienically brewed and processed containing plenty of beneficial microorganisms.

• Applied Biological Chemistry
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• v.36 no.4
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• pp.277-283
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• 1993

In order to brew foxtail millet wine, a folk wine of Cheju, properties of raw materials, optimum brewing conditions were inveatigated. Carbohydrate and crude fat content of glutinuous foxtail millet are 71.27% and 3.47%, respectively. Since the ratio of water to steamed millet and ethanol concentration of wine showed negative correlation, less than 250% water had to added to steamed millet to maintain ethanol concentration in wine above 13%, Sugar consumption and ethanol production increased rapidly for the first 2 days, and main fermentation was done in 4 days. Ethanol concentrations were $13.0{\sim}13.4%$ when foxtail millet was used, and they were $14.0{\sim}14.3%$ for the mixture substrates of 90% millet and 10% rice or barley. Organic acids in millet wine were lactic acid, malic acid and succinic acid. The residual carbohydrates after fermentation were mainly xylose and oligosaccharides. A trace of methanol was detected in millet wine. The content of fusel oil was low, while the concnetration of organic acids was high. Optimum conditions for millet wine-making were as follows. Glutinuous foxtail millet with 10% rice as fermentation source need to be soaked in water and steamed for enough time. Water was added to steamed millet with the ratio of 2 : 1. The resulting mixture was stmnultaneously saccharified and fermented by Aspergillus orzae and Saccharomyces cerevisiae IAM 4274 at $20^{\circ}C$ for a week. Millet wine was prepared after filtering fermented broth while pressing for a week.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.6
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• pp.834-839
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• 2012

The physicochemical and sensory characteristics of Yakju fermented with different ratios of Taraxacum platycarpum (dandelion) root powder (0, 5, 10, and 15%) were investigated. The pH of Yakju decreased and the total acidity and sugar content increased according to the addition of dandelion root powder. Dandelion root powder (15%) showed significantly higher reducing sugar content on the 3rd day of fermentation compared with other groups, including the control. Also, further exposure of fermentation time showed a declining pattern of reducing sugar content. Including control, the alcohol content increased in all Yakju samples fermented with dandelion root powder as fermentation progressed. The Yakju fermented with 5% dandelion root powder showed the highest sensory scores for color, aroma, taste, swallowing, and overall acceptability as $6.38{\pm}1.27$, $5.58{\pm}1.02$, $5.79{\pm}0.98$, $6.08{\pm}1.21$, and $5.96{\pm}0.91$, respectively. In the present study for the production of Yakju, 5% dandelion root powder was the most appropriate amount to be added for the production of Yakju. The result obtained here may provide fundamental data for the traditional Yakju industry, which is interested in using a variety of natural resources.

• Korean Journal of Food Science and Technology
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• v.43 no.6
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• pp.742-746
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• 2011

To increase the quality of Korean traditional yakju, we prepared seed cultures by fermentation at $20^{\circ}C$ for 2 days after addition of 140% water, 3% nuruk and 1.5% yeast into cooked rice. After the 200% cooked rice, 120% water and 0.08% commercial saccharifying enzyme were added to seed cultures and fermented for 2 days at $20^{\circ}C$, wild ginseng was added and then further fermented for 5 days. Physicochemical properties of traditional yakju were investigated. Ethanol was produced (18.5%) by the addition of 1.2% wild ginseng. However, ethanol content was not increased by addition of microwave treated-wild ginseng and rice (either cooked rice or raw). The traditional yakju obtained by fermentation at $20^{\circ}C$ for 5 days, after 90 sec of microwave treated-wild ginseng was added into main fermentation broth, showed good total acceptability and also contained 791 ppm saponin.

• Korean Journal of Food Science and Technology
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• v.40 no.1
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• pp.21-30
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• 2008

In this study, the antioxidant activities of 27 medicinal herbs and plants were measured. The dried medicinal herbs and plants were pulverized and extracted by water, 15% ethanol, and 45% ethanol, respectively at above $80^{circ}C$ for 90 minutes. The original and diluted extracts were tested for their antioxidant activities by 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical-scavenging activity assay. Cornus officinalis (C) and Scutellaria baicalensis (S) were selected to develop rice wines with higher antioxidant activities, based on the result of the 45% ethanol extraction. The rice wine developed using sample showed the highest antioxidant activity as comparing to those of other commercial rice wines. The rice wine samples were analyzed for titratable acidity, pH, $^{\circ}Brix$, reducing sugar content, color (L, a, b), amino-acidity, and ultraviolet absorption. The preferences for color, aroma, and overall acceptability were determined using a 9-point hedonic scale by 150 consumers. The sweetness, sourness, fruitiness, color, and medicinal herb-taste levels of the developed rice wines were also evaluated, using a 9-point just-about-right scale. The mean overall acceptability score of c (5.54) was higher than that of sample S. Based on the results, the sourness and medicinal herb-taste levels of sample s should be modified to higher levels, and the fruitiness of sample S also needs to be adjusted. For a future study, the final compositions of the developed rice wines will be adjusted for product launching based on the preference test data acquired in this study.

• Food Science and Preservation
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• v.22 no.3
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• pp.361-368
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• 2015

In this study, the fermentation characteristics of Yakju were investigated by addition of protein and lipid. These are classified according to raw material (rice, glucose) and inducing substance (rice protein, rice lipid). Alcoholic fermentation occurred at $25^{\circ}C$, after 14 days. The results of this study were as follows: Alcohol content of Yakju with rice protein was higher than those of other samples. The pH and glucose of rice Yakju were detemied to be 4.86~5.13 and 4.17~4.86, respectively. Titratable acid and the total amino acid content of the Yakju with rice protein were the highest among other samples. The optical density contents of the rice Yakju and glucose Yakju were 0.52~0.653 and 0.27~0.61, respectively. The concentration of organic acids in rice Yakju (433.98~519.31 mg%) was higher than that of glucose Yakju (303.76~387.50 mg%). The major organic acid components of the Yakju were succinic, citric, acetic and lactic acids. The nitrogen compound concentrations of rice Yakju (4377.38~10208.06 ppm) was higher than that of glucose Yakju (671.20~9368.93 ppm). The protein odor correlation coefficient was 0.98 (p<0.001) showing a very high correlation coefficient, while lipid odor coefficient showed a negative correlation with -0.038 (p<0.458).

• Microbiology and Biotechnology Letters
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• v.39 no.3
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• pp.274-280
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• 2011

Effects of rice varieties, fermentation temperature, nuruks and yeast on the quality of yakju (Korean traditional rice wine) were investigated. Among various yakju made by using some rice varieties, Chucheong yakju produced the highest ethanol of 18.9%. The maximum amount of ethanol was produced when 2% nuruk and 0.8% yeast were added to cooked Chucheong rice and fermented at $20^{\circ}C$ for 10 days. This Chucheong yakju also showed the best overall acceptability. Changes of physicochemical properties and sensory evaluation of the 3 kinds of Chucheong yakju made by cooked rice and uncooked rice and gruel rice were investigated during fermentation. Ethanol contents of uncooked rice- Chucheong yakju and gruel rice- Chucheong yakju were significantly increased from 10.6% and 9.9% after 3 days fermentation to 17.1% and 17.2% after 7 days fermentation. Sensory evaluation revealed the gruel rice - Chucheong yakju was the best in total acceptability with sweety and refreshing tastes.

• Korean Journal of Food Science and Technology
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• v.37 no.1
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• pp.61-66
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• 2005

Korean traditional rice wine Takju and Yakju were manufactured using 2-step-brewing method. To investigate microflora involved in fermentation step, number of microorganisms, pH, titratable acidity, and alcohol contents of Takju and Yakju were measured. In Takju and Yakju, although not significantly, $1.1{\times}10^{8}$ and $2.0{\times}10^{6}\;CFU/mL$ lactic acid bacteria at initial stage of second fermentation decreased to $8.3{\times}10^{6}\;and\;1.0{\times}10^{4}\;CFU/mL$ at the end of second fermentation, respectively. For Takju, micrococci and yeast occupied 80 and 20% at initial stage of second fermentation, whereas bacteria and yeast occupied 35 and 65% at the end of second fermentation, respectively. Yeast occupied 88% throughout the second fermentation of Yakju. The main yeast isolated from both Takju and Yakju was identified as Saccharomyces cerevisiae using API 20C AUX kit. The yeast strain Candida magnoliae was also detected during fermentation of Takju and Yakju.