• Korean journal of food and cookery science
• /
• v.32 no.4
• /
• pp.466-475
• /
• 2016

Purpose: This study investigated the quality characteristics and antioxidant effects of Yakju added with rose, camellia, or cockscomb flower during fermentation. Methods: The quality characteristics and antioxidant effects were estimated including pH, amino acidity, total acid, ethanol content, color value, sensory test, electric donating ability, nitrite-scavenging ability, and ferrous ion chelating effect. Results: The pH values of Yakjus added with rose, camellia, or cockscomb flower were decreased after 2 days of fermentation and then increased after 4 days of fermentation, with final pH ranging from 4.15 to 4.27. Total acid content and amino acidity were increased during fermentation. The ethanol content in Yakjus fermented with rose, camellia, or cockscomb flower was rapidly increased after 2 days of fermentation, reaching the maximum content of 19.1% after 8 days of fermentation. In color evaluation, the L values of Yakjus added with rose, camellia, or cockscomb flower did not changes during fermentation, whereas values of a and b were increased. Total phenolic compound contents in Yakjus added with rose, camellia, or cockscomb flower were 0.67, 0.59, and 0.52 mg/mL, respectively. Total flavonoid contents in Yakjus added with rose, camellia, or cockscomb flower were 0.20, 0.09, and 0.26 mg/mL, respectively. In sensory test, the overall acceptability of Yakjus added with cockscomb flower was higher than that of Yakju added with rose or camellia flower. However, the difference was not statistically significant (p<0.05). Electron donating ability and nitrite-scavenging abilities were the highest in Yakjus added with rose flower, whereas ferrous ion chelating effect was the highest in Yakjus added with cockscomb flower. Conclusion: These results indicated that Yakjus added with rose, camellia, or cockscomb flower might have valuable functional properties due to their antioxidant effects.

• Journal of the East Asian Society of Dietary Life
• /
• v.1 no.1
• /
• pp.99-111
• /
• 1991

In each nuruk using today, effect of pH on glucoamylase activity and viable cell count of yeast and bacteria was measured. Common components during fermentation, alcohol, acetaldehyde and acetone, amino acid composition, and total sugars and mineral content were determined in yakju(korean wine) brewed from different ingredients and by different methods. Results are summarized as follows ; 1. The lower the pH, the lower the glucoamylase activity in JK, BK, JK-S BK-S and JN. But the higher the glucoamylase activity ratio in Koji and KN. 2. Yeast and bacteria cell count could not determined in nuruk inoculated of seed. In JK, BK and JN, yeast cell count was 50${\times}$104∼80${\times}$104, bacteria cell count was 5${\times}$106∼24${\times}$106. 3. In yakju during fermentation, pH was higher in RU, total acidity content was higher in ST-N, ST-K, RU and ST-RUPO and alcohol content was lower in RUPO and ST-RUPO. 4. Ethanol and acetaldehyde content were highest in dukyunju. Trace amount of acetone was determined only in ST-K, RUPO and ST-RUPO . n-Propyl alcohol content was higher in ST-K, ST-RUPO and ST-N, iso-butyl alcohol content was higher in L-RUPO, Dukyunju and Songyupju and iso-amyl alcohol content was higher in Songyupju, RU, L-RUPO and Dukyunju. 5. In amino acids composition of each yakju, Pro, Ala and Val content was higher than other amino acids. Total amino acids content was the highest in Dukyunju and second highest in ST-N, NH3 was higher in ST-N, Dukyunju, RUPO than other samples. 6. Total sugars content was the highest in ST-N and second highest in RU. 7. P, K and Mg content were higher in Dukyunju and ST-N than in other samples. In Dukyunju, Ca and P ratio was 0.075 because of low Ca content and high P content.

• Culinary science and hospitality research
• /
• v.21 no.3
• /
• pp.232-247
• /
• 2015

This study was carried out to evaluate the quality of characteristics of the Takju, Yakju, spirit made by various pulse crop Nuruks which were made by Whyangonkuk(whole wheat, mung beans), Naebubijeonkuk mung beans, wheat flour, millet), Daedukuk(whole wheat, soybean). pH, Brix, total acidity, cell numbers of yeast and alcohol content of brews were analysed and flavors, organic acids, sensory evaluation of Takju, Yakju, and spirit were employed to analyze for current study. Results showed that pH value of Whyangonkuk brews during fermentation decreased the lowest, and Brix value also decreased. Total acidity of Whyangonkuk at the initial and final stage of fermentation revealed the most. Alcohol contents of Naebubijeonkuk brew presented the highest at the initial stage of fermentation, but there were no significant differences among Whyangonkuk, Naebubijeonkuk and Daedukuk at the final stage of fermentation. Cell numbers of yeast were found the most in Daedukuk at the first stage of fermentation, and cell numbers started to decrease after 2 days, but there were no significant differences at the final stage(p<0.05). In terms of analysis of flavor components, acetone and n-amyl alcohol were not detected in Takju, Yakju, and spirit. n-butanol was detected the most value followed by i-amyl alcohol. Fusel oil were detected the highest level at spirit, but no differences among Takju, Yakju and spirit. In analysis of organic acids, fumaric acid and formic acid were detected in Takju and Yakju. while 7 kind of organic acids were detected. Lactic acid showed the highest level in organic acid analysis. Takju and Yakju made by Whyangonkuk showed the highest score, and Daedukuk showed the opposite result but there were no differences in spirit made by Whyangonkuk, Naebubijeonkuk, and Daedukuk. As a result of this study, Whyangonkuk presented the most desirable Nuruk.

• Korean Journal of Food Science and Technology
• /
• v.36 no.5
• /
• pp.818-822
• /
• 2004

Gastroprotective effects of Korean rice-wine (Yakju) in two types of acute experimental gastric ulcer induced in rats and in mice were evaluated. Korean rice-wine were administered to 24-hr fasted rats 30 min before administration of 60% EtOH in 150 mM HCl or absolute ethanol. Korean rice-wine prevented formation of gastric ulcers induced by 60% EtOH in 150 mM HCl at oral doses of 250-1,000mg/kg and reduced gastric ulcers induced by absolute ethanol at oral doses of 62.5-1,000mg/kg, and inhibitory effect against 30% alcohol treatment for 7 days (twice/day). These results suggest Korean rice-wine have inhibitory effects on gastric lesion and ulceration.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.45 no.2
• /
• pp.239-246
• /
• 2016

This study was performed to investigate changes in characteristics of Umbilicaria esculenta Yakju added with 0.5% and 1% grapefruit seed extracts (GSE) during storage for 75 days at $25^{\circ}C$ and 165 days at $4^{\circ}C$. Quality characteristics of pH, titratable acidity, turbidity, total aerobic microbes, and ethanol, glucose, acetic acid, and lactic acid contents were analyzed. Control group showed sharply increased pH, titratable acidity, turbidity, and acetic acid and lactic acid has contents while the 0.5% and 1% GSE groups added to Yakju did not show significant changes in pattern (P<0.05). Total aerobic microbes increased rapidly during storage from 15 days in the control group, and the 0.5% and 1% GSE groups showed gradually increased total aerobic microbes from 30 days of storage compared to the control group (P<0.05). In addition, in all test groups, coli, yeast, and fungus were not detected. Ethanol content slightly increased during storage and glucose content slightly decreased, but there were no large changes during storage between the control group and GSE groups. Therefore, 3 months and $4^{\circ}C$ are considered safe for 6 months of storage, and GSE is effective to improve shelf-life and quality improvement of Yakju.

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

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.46 no.7
• /
• pp.848-856
• /
• 2017

This study aimed to investigate the effect of rice nuruk prepared from rice with different degrees of milling (0, 10, 30, 50, and 70%) on physicochemical qualities of yakju. The results indicated significant differences in the qualities of yakju prepared using rice nuruk from rice with different degrees of milling. Specially, pH, amino acidity, brownness, b value, and color difference were significantly reduced as the degrees of milling increased, whereas contents of alcohol and volatile acid, reducing sugar, and L value were increased. Malic acid, succinic acid, and lactic acid were the main organic acids in yakju, and there were significant differences among the treatments in malic acid, lactic acid. However, there was no tendency according to different degrees of milling. In addition, contents of total free amino acids and nitrogen compounds showed no tendency according to degrees of milling, whereas the content of aspartic acid showed a tendency to decrease significantly. The content of 2-phenyl alcohol in the volatile flavor components showed a tendency to increase significantly with higher degree of milling of rice nuruk, whereas contents of n-propanol and iso-amyl alcohol tended to decrease significantly.

• Applied Biological Chemistry
• /
• v.39 no.5
• /
• pp.338-342
• /
• 1996

Fruit of Lycium chinense Miller was known to Korean as traditional medicine that has effective components for strengtherning function of human body, especially liver. To study characteristics of the wine and Yakju made by fruit Lycium chinense Miller, general components such as organic acid, methanol, ester, fusel oil and $SO_2$ were analyzed after storing them for 10 and 20 days at $20^{\circ}C\;and\;30^{\circ}C$, respectively. Organic acid contents of the wine were mainly lactic, malic, tartaric and acetic acid. Ester and fusel oil contents of the wine were $4.0{\sim}5.0\;mg%$ and $12{\sim}30\;mg%$, respectively, and the values were smaller than those of the Yakju. Methanol content of the wine was $25{\sim}27\;mg%$. Storage temperature in terms of the quality of the wine and Yakju was better in $20^{\circ}C\;than\;30^{\circ}C$. Treatment of the wine and Yakju either by adding 100 ppm of $SO_2$ or heating at $60^{\circ}C$ for 30 min was better in quality than control for storage.

• The Korean Journal of Mycology
• /
• v.38 no.2
• /
• pp.184-188
• /
• 2010

The goal of this study was to screen a useful yeast for Korean traditional pear Yakju (KTPY) brewing and develop its brewing process. Cooked non-glutinous rice and nuruk were mixed, and added into pear juice with various Saccharomyces cerevisiae and then fermented at $25^{\circ}C$ for 7 days. Among several alcohol fermentation yeasts, ethanol contents was the highest in pear Yakju made by S. cerevisiae K-7 and also showed high ethanol content in pear Yakju which was made by commercial S. cerevisiae C-2. Therefore, we selected S. cerevisiae K-7 and S. cerevisiae C-2 as suitable yeasts for brewing of KTPY. Maximal ethanol production (10.4%) was obtained when cooked non-glutinous rice (100 g) and nuruk (30 sp/g) were mixed and added into pear juice (600 ml) with S. cerevisiae K-7 (5%) and fermented at $25^{\circ}C$ for 7 days and also its antihypertensive angiotensin I-converting enzyme (ACE) inhibitory activity was 57.2%. Addition of antihypertensive starchy materials into the mash was not affected in ACE inhibitory activity and total acceptability of KTPY.

• Food Science and Preservation
• /
• v.22 no.3
• /
• pp.353-360
• /
• 2015

Yakju, a Korean traditional alcoholic beverage, is made from rice and Nuruk. In this study, the fermentation characteristics of Yakju was investigated using rice and rice starch. Ingredients was classified into raw material (rice, rice starch) and starter (enzyme supplements, modified Nuruk, traditional Nuruk, and yellow rice koji) for fermentation. The crude protein content of rice, rice starch, and starter were determined as follows (%): rice 6.69, rice starch 0.44, enzyme supplements 7.84, modified Nuruk 15.29, traditional Nuruk 14.28, and yellow rice koji 7.28. The alcohol content of rice with traditional Nuruk ($20.13{\pm}0.12%$) was higher than other Yakju. The concentration of organic acids of rice starch-based Yakju (389.83~538.34 mg%) was higher than that of rice Yakju (259.27~357.70 mg%). The concentration of nitrogen compound of rice Yakju (498.38~5976.93 ppm) was higher than that of rice starch-based Yakju (600.43~4463.79 ppm). In line with these findings, further studies will be necessary for the quality analysis of the rice, rice starch and fermented starter (enzyme supplements, modified Nuruk, traditional Nuruk and yellow rice koji).