• Korean Journal of Food Science and Technology
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• v.40 no.5
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• pp.551-557
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• 2008

In order to investigate the effect of different ingredients on the quality of Korean rice wines, 30% of rice were substituted by malt, corn, potato, soybean, glutinous millet, unpolished rice, glutinous rice, or non-glutinous rice, when rice wines were prepared. Physicochemical and sensory characteristics of the rice wines from the varying ingredients were evaluated. Sample rice wines were analyzed for ethanol, pH, total acid, amino acid, soluble solid, coloring degree, UV absorbance, reducing sugar, organic acids, and free sugars. After fermentation for 16 days, the ethanol contents ranged from 13.28 to 16.23%, while the total acid levels were within the range of 0.27 to 0.32%. The amino acid contents in eight samples ranged from 0.18 to 0.36%, while the soluble solid contents were within the range of 8.35 to $11.1^{\circ}$Bx. Among the eight samples tested, rice wine prepared with malt showed the highest level of coloring degree, UV absorbance, and reducing sugar levels, while rice wine prepared with potato showed the lowest value. Organic acid contents of rice wines prepared with soybean, glutinous rice, and non-glutinous rice showed the highest levels of succinic acid followed by acetic acid, citric acid, malic acid, and pyroglutamic acid. Free sugar contents of all rice wines showed the higher levels of glucose followed by fructose and maltose. Rice wines prepared with unpolished rice and corn showed the same highest overall sensory preference. By descriptive analysis, the overall mean sensory intensities of samples prepared with glutinous rice and non-glutinous rice, showed similar levels of 'sweetness', 'fruitiness', and 'freshness of aroma', while those samples prepared with soybean, glutinous millet, and potato showed stronger intensities of 'nuruk', 'grain aroma', and 'yellowness'. Rice wine prepared with corn showed middle ranges in all sensory attributes tested.

• Food Science and Preservation
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• v.22 no.3
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• pp.369-376
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• 2015

This study was performed to develop the maufacturing processes of Makgeolli using red ginseng starch (RGS). After the fermentation of RGS with koji, nuruk, and yeast, the different temperature effects on the number of the yeast cells, the content of organic acid, free sugars, and total acid, and pH were investigated. There were no changes in the composition of the yeast cell number and content of organic acid amd during 20 days at $4^{\circ}C$. The content of free sugars (sucrose, glucose and mannose) and the pH value of red ginseng Makgeolli decreased during storage at $4^{\circ}C$. This meant that the total acid content and pH value increased after organic acid was produced from fermentation. Therefore, red ginseng Makgeolli is highly acidic and sour. Since high acidity helps improve storage conditions, so this developed red ginseng Makgeolli is considered safe for consumption. Furthermore, the total content of ginsenoside was 2.47 mg/mL, which was differentiate Makgeolli using red ginseng starch, with others. Therefore, new red ginseng Makgeolli is rich in organic acid, free sugars, and ginsenoside. As a result, its storage, taste, and flavor improved.

• Korean journal of food and cookery science
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• v.22 no.6 s.96
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• pp.914-922
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• 2006

Korean traditional rice wines and liquors have been long brewed using nuruk or koji, cooked rice, How, yeast and some medicinal plants or herbs. The rosemary shrub (Rosmarinus officinalis L), belonging to the Labiatae family, is well recognized for its aromatic, antioxidant, antimicrobial and antitumoral properties. In this study, we investigated the effect of rosemary addition on the quality characteristics of Korean traditional rice wine. Wines containing different rosemary concentrations (0, 10, 20 or 30%) were ripened for 0, 5, 10, 15 and 20 days at 25C. The following quality characteristics were compared: pH, total acid, titratable acidity, amylase activity, color, reducing sugar amount, total sugar and ethanol. Although total acid increased, the pH of rosemary wine rapidly decreased during the rot 5-days of ripening, and these two changes were greatest in the wine containing 10% rosemary. The amount of both reducing sugar and ethanol in the wine rapidly increased during the rot 5-days of ripening, while total sugar content of rosemary wine decreased significantly with increasing ripening periods(p<0.05). According to the Hunter's color results, a significant color change in 'L' value was observed with increasing fermentation period in the wine containing 10% rosemary. Although 'a' value of control (0% rosemary liquor) increased during the ripening period, the addition of rosemary did not significantly affect 'a' or 'b' values. The transmittance of rosemary wines increased with increasing rosemary content but decreased throughout the ripening periods. Amylase activity decreased with increasing rosemary content, especially after a 5-day ripening period.

• Food Science and Preservation
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• v.20 no.4
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• pp.564-572
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• 2013

We investigated the quality characteristics of brewing brown rice vinegar through a traditional static fermentation process. Accordingly, we decided to compare the physicochemical characteristics of brewing vinegar at different temperatures and filtration methods. In four to five weeks' time, the acetic acid fermentation exhibited the highest titratable acidity and then it eventually decreased. The titratable acidity was affected by the filtration method. It was revealed that the titratable acidity was higher in the forced filtration than the traditional filtration method. Various organic acids were detected in order to initialize the fermentation stage and as the fermentation progressed, only the acetic acid could be detected. The total free amino acid content was higher at a temperature of $30^{\circ}C$ than at $20^{\circ}C$. Moreover, the free amino acid content was dependent on the acetate content during the acetic fermentation process. The main bioactive substance of the ${\gamma}$-aminobutyric acid content was more than twice at a fermentation temperature of $30^{\circ}C$ compared to the fermentation temperature of $20^{\circ}C$. Furthermore, the total amino acid and essential amino acid content at a temperature of $30^{\circ}C$ was excellent. The quality of the brown rice vinegar via forced filtration method at a temperature of $30^{\circ}C$ was the most excellent. Based on these results, the fermentation temperature and the use of nuruks (fermenting agent) affected the quality of the brown rice vinegar, and an appropriate method to consider its purpose is required.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.1
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• pp.137-144
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• 2015

Kyejang is a Korean traditional beverage manufactured from medicinal plants and fruits using honey, sugar, or starch in cold water. In this study, cinnamon-containing kyejang, which is a type of beverage Jang, was reproduced based on Imwonsibyukji's method published in 1827 in the Korean literature. Kyejang made by nuruk, cinnamon, and medicinal plants was prepared at various temperatures and periods. Kyejang was assayed for physiochemical properties (pH and acidity), contents of metabolites (organic acids, sugars, and amino acids), and sensory characteristics (aroma and taste). During fermentation, content of organic acids (e.g. lactic acid, acetic acid, and shikimic acid) increased, which lowered pH, increased acidity, and increased intensity of sour taste. In the case of free sugars, fructose and maltose levels decreased while glucose and mannitol levels increased during fermentation periods, and sweetness decreased. The main amino acid in kyejang was tryptophan, followed by asparagine, proline, and arginine. The sensory evaluation score of overall preference was highest for kyejang which was fermented at $20^{\circ}C$ for 3 days. The results will be provide the basic data of fermentation conditions for standardized manufacturing process of kyejang.

• Applied Biological Chemistry
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• v.13 no.2
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• pp.111-129
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• 1970

As a series of studies on the nucleic acids and their related substances 210 samples were collected from 76 places such as farm soil, compost of heap, nuruk and meju to obtain microbial strains which produce 5'-phosphodiesterase. From these samples total of 758 strains were isolated by the use of dilution pour plate method. For all isolated strains primary screening of the productivity of RNA depolymerase was performed and useful strains with regard to 5'-phosphodiesterase productivities were identified. For these useful strains optimum condition, the effect of various compounds on the activity of 5'-phosphodiesterase, and the optimum condition for enzyme reaction were discussed. The quantitative of 5'-mononucleotides produced by the action of 5'-phosphodiesterase was performed using anion-exchange column chromatography and their identified was done by paper chromatography, thinlayer chromatography, ultra violet spectrophotometry, and characteristic color reaction using carbazole and schiff's reagent. (1) Penicillium citreo-viride PO 2-11 and Streptomyces aureus SOA 4-21 from soil were identified as a potent 5'-phosphodiesterase producing strains. (2) Optimum culture conditions for Penicillium citreo-viride PO 2-11 strain isolated were found to be pH 5.0 and $30^{\circ}C$, and the optimum conditions for enzyme action of 5'-phosphodiesterase were pH 4.2 and $60^{\circ}C$. Best carbon source for the production of 5'-phosphodiesterase was found to be sucrose and ammonium nitrate for nitrogen source. Addition of 0.01% corn steep liquor or yeast extract exhibited 20% increase in the amount of 5'-phosphodiesterase production compared to the control. 5'-phosphodiesterase produced by this strain was activated by $Mg^{++},\;Ca^{++},\;Zn^{++},\;Mn^{++}$ and was inhibited by EDTA, citrate, $Cu^{++},\;CO^{++}$. 5'-phosphodiesterase produced 5'-mononucleotide from RNA at a rate of 65.81%, and among the 5'-mononucleotides accumulated 5'-GMP only was found to have flavorous and the strain was also found lack of 5'-AMP deaminase. Productivity of flavorous 5'-GMP was found to be 186.7mg per gram of RNA. (3) Optimum culture canditions for the isolated Streptomyces aureus SOA 4-21 strain were pH 7.0 and $28^{\circ}C$, and the optimum conditions for the action of 5'-phosphodiesterase were pH 7.3 and $50^{\circ}C$. The best carbon source for 5'-phosphodiesterase production was found to be glucose and that of nitrogen was asparagine. Addition of 0.01% yeast extract exhibited increased productivity of 5'-phosphodiesterase by 40% compared to the non-added control. 5'-phosphodiesterase produced by this strain was activated by $Ca^{++},\;Zn^{++},\;Mn^{++}$ and was inhibited by citrate, EDTA, $Cu^{++}$. It was also found that the strain produce 5'-AMP deaminase in addition to 5'-phosphodiesterase. For this reason although decomposition rate was 63.58% the accumulation of 5'-AMP, 5'-CMP, 5'-GMP and 5'-UMP occurred by the breakdown of RNA. In the course of these reaction 5'-AMP deaminase converted 60% of 5'-AMP thus produced into 5'-IMP and flavorous 5'-mono nucleotide production was significantly increased by this strain over the above mentioned one. Production rates were found to be 171.8mg per grain of RNA for 5'-IMP and 148.2mg per gram of RNA for 5'-GMP, respectively.