• Journal of the Korean Society of Food Culture
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• v.30 no.3
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• pp.377-386
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• 2015

The purpose of this research was to appraise physicochemical properties by utilizing different Mit-sool, Juk, Seolgi-tteok, and Godubap, to produce traditional liquor. In all experimental plots, pH and amino acidity tended to increase with duration of fermentation. Titratable acidity displayed a very high number on the second day but then tended to decrease as fermentation progressed. Sugar contents were highest on the fourth day and tended to decrease with time. Alcohol content increased sharply at the initial stage of fermentation and increased gradually. On the 15th day, traditional liquor made with Godubap recorded the highest alcohol content. Common free sugar components were glucose and sorbitol. Common free organic acid components were lactic, succinic, citric, tartaric, malic, and acetic acids. Volatile flavor compounds were six alcohols, five esters, three aldehydes, and two ketones. Regarding overall acceptability in the sensory evaluation, traditional liquor using Seolgi-tteok as Mit-sool scored the highest. Overall, even though different types of Mit-sool had different physicochemical properties, there were no significant differences in volatile flavor compounds or sensory evaluation scores.

• Food Science and Preservation
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• v.5 no.4
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• pp.374-379
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• 1998

A vinegar was prepared from uncleaned rice by two step fermentation, alcohol fermentation followed by acetic acid fermentation. The contents of alcohol reached to 10.8% during the alcohol fermentation of uncleaned rice with nuruk, and acidity reached to 5.78% during the acetic acid fermentation. Acidity and pH of vinegar of two step fermentation were higher than those of commercial vinegars. 'L' value(Light) of the vinegar was lower, 'a' and 'b' value were higher than those of commercial vinegars. The contents of acetic acid, malic acid, citirc acid and tartaric acid were hish in organic acid of vinegars. The content of each ofganic acid in vinegars was remarkably different. The content of free amino acids was 2199.7${\mu}\ell$/ml in the vinegar produced by two step fermentation which is higher than that of others.

• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.1
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• pp.48-52
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• 1993

To furnish basic data for the utilization of leaf mustard as a raw material of salted and fermented vegetable food, major chemical compositions of Dolsan Leaf Mustard (DLM) were investigated. The moisture and ash contents of DLM were 87.5% and 1.4%, respectively. Compared with other Korean traditional or Japanese leaf mustard, DIM contained more crude protein (3.8%) but less crude fat (0.3%) and crude fiber (1.3%). As an alkali food, leaf and leat stalk had pH of 5.7 and 5.8, titratable acidity of 687 and 318mg/100g and alkalinity of 2.5 and 5.2, respectively. The major free sugar in DLM was glucose and fructose was also detected in a small amount. The contents of total and reducing sugar in leaf and leaf stalk were 574, 352, 820 and 538mg%, respectively. Total amino acid contents of leaf and leaf stalk were 8.0 and 2.5% on wet basis. Although the amino acid compositions of leaf and leaf stalk were different each other, glutamic acid and proline were the major amino acids in both of the leaf and leaf stalk. Significantly higher amount (ca.10.3-fold) of free amino acid was present in leaf (3074mg%) than in leaf stalk (298mg%). Glutamic acid and aspartic acid were the major free amino acids and essential amino acid contents in leaf and leaf stalk were 869 and 68mg% being 22.9 and 28.3% of total free amino acids.

• Applied Biological Chemistry
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• v.37 no.6
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• pp.421-426
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• 1994

This study was carried out to investigate the effect of $CaCO_3$ on the Chungkookjang Meju fermentation. B. subtilis was cultured on the Meju added 0, 0.01, 0.1, 1% $CaCO_3$, respectively, and the chemical composition, protease activity, amino acid and vitamin B complex were examined with fermentation time. The inner temperature of the $CaCO_3$ treatments during fermentation was increased as compared with the control group. Titratable acidity in Meju decreased as $CaCO_3$ concentration increased. And protease activity and amino-nitrogen content were however high in same order. The content of amino acid was on the increase in every treatments, it made no difference between $CaCO_3$, treatments and the control. Vitamin B complex content in the $CaCO_3$ treatments was increased than in the control. The 0.01% added treatment showed the highest amount of vitamin B complex content in all the treatments.

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

• Korean Journal of Food Science and Technology
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• v.48 no.3
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• pp.223-230
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• 2016

We investigated the fermentation characteristics of yakju made with nuruk extracts. Alcoholic fermentation was performed in an incubator set at $25^{\circ}C$ for 14 days. The study results are as follows: the alcohol content of yakju made with modified nuruk (18.67%) was higher than that made with other nuruk extracts (14.80-17.50%). The pH value of this modified nuruk (4.13) was higher than that of traditional nuruk (3.70-4.00). The yakju containing modified nuruk showed the highest acidity (3.64 mL/10 mL), amino acidity (4.72 mL/10 mL), soluble solid ($1.20^{\circ}Bx$), and color difference (39.78). The concentration of organic acids in traditional nuruks was 212.25-312.97 mg/100 mL, whereas that in modified nuruk was 295.92 mg/100 mL. Nitrogen compound concentrations in modified nuruk (2285.89 mg/L) were 2-14 times higher than that in traditional nuruk. Nitrogen compound concentration and amino acidity are the physiochemical characteristics with the highest impact on off-flavor and browning of yakju. In order to reduce these unfavorable characteristics, material with a lower protein content should be used.

• Microbiology and Biotechnology Letters
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• v.43 no.3
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• pp.227-235
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• 2015

The objective of this study was to improve the quality of Korean rice wine with wild type yeast strains isolated from various traditional Korean fermented foods. Herein the fermentation and sensory characterization of wild yeast, for the purposes of brewing Korean rice wine, was investigated. 12 yeast strains were examined for their ethanol and glucose tolerance. In addition, the pH, soluble solids, acidity, amino acidity, ethanol content, organic acids, and volatile compounds were also studied for the alcoholic beverages made with the wild yeasts. Almost all Saccharomyces genera yeasts were showed to have a tolerance at 10% ethanol, but non-Saccharomyces genera yeasts displayed a low tolerance. The alcoholic beverages fermented by non-Saccharomyces yeasts demonstrated higher levels of soluble solids, titratable acidity, amino acids, and lower ethanol content, when compared with the alcoholic beverages fermented by Saccharomyces genera yeasts. The organic acid content, such as malic acid, acetic acid, and succinic acid, was seen to also be higher. The electronic nose was analyzed, and discriminant function analysis (DFA) was used for discriminating wild yeast strains. The DFA plots indicated a significant separation of Saccharomyces genera and non-Saccharomyces yeast strains. For volatile compounds, ethyl acetate from non-Saccharomyces yeasts, and ethanol from Saccharomyces genera yeast, a high area ratio was observed.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.3
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• pp.381-387
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• 2003

This study was performed to establish the fermentation method of non-steamed brown rice vinegar using starch saccharifing enzyme. During vinegar fermentation, initial pH had increased in the higher concentration of alcohol and acetic acid. Final pH was gradually changed to pH 2.90~3.44 from 3.44~4.06. The higher total acidity of brown rice vinegar resulted from the higher alcohol concentration. The total acidity was slightly dropped after gradually increasing from the starting of fermentation. Initial pH was decreased from 3.67 to 3.16. The total acidity was gradually increased from the first day of fermentation with 1.02, it was 1.54 on the second day after fermentation and there was a tendency to decreased after the highest values with 6.53 fermentation for 12 days. In organic acid composition, oxalic, malic, acetic, citric, and succinic acid were detected. The total free amino acid was decreased to 1,121 mg%. The major amino acids were ${\gamma}$ -aminobutyric acid, $\alpha$-aminoadipic acid and alanine, and ${\gamma}$-aminobutyric acid was the highest (539 mg%). The mineral contents such as P and K was high in sample and followed by Mg, Na, Ca.

• Food Science and Preservation
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• v.24 no.7
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• pp.1034-1042
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• 2017

The quality characteristics of Yakju and survival rate of yeast were investigated by modifying the drying method for the cold adapted yeast strain Saccharomyces cerevisiae Y297 (SCY297). Viability and fermentation characteristics of the freeze-dried, air blast-dried, and liquid SCY297 cultures were compared after storing them at $25^{\circ}C$. In addition, 5% skimmed milk, ${\alpha}$-lactose, or trehalose was added as a protective agent for examining the effects of drying methods. During the 15-week storage period, the liquid and freeze-dried SCY297 cultures containing a protective agent showed a survival rate of 80%. However, the air blast-dried SCY297 culture showed 80% survival rate only in the skimmed milk supplemented group. Compared to the untreated cells, the acidity and amino acidity of Yakju prepared using freeze-dried or air blast-dried cultures of SCY297 increased by 2 fold and 5.7 fold respectively, while the alcohol content decreased by 5.07%. Compared to the untreated cells, the pH and amino acidity of Yakju prepared using the liquid culture of SCY297 increased by 1.5 fold and 2.5 fold respectively. Although the alcohol content decreased by 2.9%, decrease rate was lower than that observed for the freeze-dried and air blast-dried yeast cultures. Therefore, the results of this study showed that using a liquid starter culture was more advantageous than using the conventional solid culture.

• Food Science and Preservation
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• v.18 no.6
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• pp.907-915
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• 2011

Moju is a low-alcoholic beverage made by filtering after boiling a mixture of makgeolli, ginseng, arrowroot, licorice root, cinnamon, jujube, ginger, and raw sugar. It is known to alleviate hangovers. To provide information for use in the development of palatable Moju, this study evaluated the physicochemical and sensory properties of 22 kinds of Moju being sold at different restaurants in Jeonju city. The mean values of obtained in the physicochemical analysis were as follows: water content, 91.28%; alcohol content, 1.09%; pH, 4.25; total acidity, 0.27%; reducing sugar content, 40.68 mg/mL; soluble solid content, 13.75 $^{\circ}Brix$; and viscosity 11.19 cP. The Lactic-, malic-, and citric- acid contents were higher than the contents of other organic acids. The sucrose content was higher than the contents of other free sugars. The mean value of the free amino acids was 175.3 mg%, lower than that of Takju, the main ingredient of Moju. It was considered that the free amino acids in Takju can be used as a substrate for the browning reaction in the process of Moju manufacture. In the sensory evaluation, the Moju with 0.15~0.25% total acidity, 10.6~13.4 $^{\circ}Brix$, and 5.73~9.57 cP was preferred.