• Microbiology and Biotechnology Letters
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• v.34 no.3
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• pp.244-249
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• 2006

In order to select the best strains to have the feasibility of Cheonghju brewing, 10 wild type yeast strains from 300 different types of Nuruk were investigated on their ethanol resistance, resistance to glucose and flocculation. The amounts of alcohol, organic acids, and volatile compounds, Brix, pH were also examined for the alcoholic beverages made with the 10 selected strains. Almost all strains showed alcohol production activities in the medium containing 18%(v/v) ethanol and 29%(w/v) glucose. The strains 90-2 showed a higher flocculation activity than other strains. Strains 54-3, 90-2 and 91-5 produced more alcohol than control strain (7.42%(w/w)) when fermented with wild type yeast strains. In addition, alcoholic beverages containing low acetic acid also showed low levels of total acidity. GC/MS analysis of the product showed 4 alcohols, 11 esters and 1 acid as volatile compounds. Selected strains were tentatively identified as Phichia sydowiorum (91-5), Zygosaccharomyces cidri (192-2 and 271-4), and as Saccharomyces cerevisiae (18-2, 54-3, 90-2, 91-2, 98-2, 99-5 and 272-7) by BIIOLOG method.

• Journal of Food Hygiene and Safety
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• v.28 no.1
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• pp.63-68
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• 2013

Ethyl carbamate (EC) is a contaminant generated in the fermentation processes of various fermented foods. In this study, residue levels of EC in 95 alcoholic beverage samples were determined by using Gas Chromatography/Tandem Mass Spectrometry (GC/MS/MS). All the samples were purified by a liquid-liquid extraction (LLE) method using dichloromethane. The LLE method enables an improvement in time and cost to detection and specificity over the conventional extraction methods. The limits of detection and quantification (LOD and LOQ) to analyze EC were 1.3 and 4.0 ng/mL, respectively. The recovery rates of EC were ranged from 90.0 to 97.5% at the levels of 50, 100, and 500 ug/L. Among traditional grain-based alcoholic beverage samples (n = 34), the average residue levels of EC in takju, yakju, and cheongju were 0.63, 7.01, and 14.11 ug/L, respectively. Among fruit-based alcoholic beverage samples (n = 48), those of EC in japanese apricot spirits, bokbunjaju, grape wines, and other fruit wines were 79.18, 1.66, 2.64, and 2.39 ug/L, respectively. Among distilled or diluted alcoholic beverage samples (n = 13), those of EC in soju (distilled or diluted), general distillates, liquors, and brandies were 0, 3.30, 8.20, and 8.52 ug/L, respectively. Therefore, this study reports that the residue levels of EC in the alcoholic beverages, distributed in the current domestic markets, did not reach its maximum allowed levels of 30 and 400 ug/L established for grape and fruit wines in Canada, respectively.

• Korean Journal of Food Science and Technology
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• v.47 no.5
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• pp.599-607
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• 2015

Fermented-Rhus verniciflua (FRV) extract is increasingly used in fermented soy products, fermented vinegars, and certain alcoholic beverages. In this study, we investigated the effects of FRV extract on the physicochemical properties of doenjang (soybean paste). Addition of FRV extract to doenjang resulted in a 28.2-45.4% increase in the amino acid content and a 1.3- to 1.5-fold increase in the concentrations of glutamic acid, which imparts a savory flavor to doenjang. The concentration of biogenic amine (BA) of the sample containing the extract was 5.3-52.6% lower than that of the control. The major components of BA included tyramine (55.1-74.6%), followed by putrescine, spermidine, tryptamine, and cadaverine, in decreasing concentrations. The organic acid concentration of the sample containing the extract was 1.2-1.3-fold higher than that of the control. The total free sugar concentration was 163.4 mg/100 g in the control and 206.6-276.8 mg/100 g in the supplemented sample, showing a 1.3- to 1.9-fold increase as the addition of the extract.

• Journal of Food Hygiene and Safety
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• v.25 no.1
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• pp.24-29
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• 2010

This study was conducted to estimate the contents of heavy metals including lead, cadmium, arsenic and total mercury in alcoholic beverages in Korea. Concentration of Hg was analyzed by gold amalgamation method, using mercury analyzer, while concentration of Pb, Cd and As was analyzed by ICP-MS. Concentration (${\mu}g/kg$) of heavy metal in fermented liquors were; for Pb $9.9\;{\pm}\;8.4$(0~38.0), Cd $5.8\;{\pm}\;4.9$(0~5.4), As $28.6\;{\pm}\;19.4$(1~96.4), Hg $0.7\;{\pm}\;1.2$(0~10.6). Concentration (${\mu}g/kg$) of distilled liquors were ; for Pb $4.4\;{\pm}\;5.7$(0~29.3), Cd $2.0\;{\pm}\;2.5$(0~10.3), As $12.0\;{\pm}\;17.0$(0~95.6), Hg $0.2\;{\pm}\;0.3$(0~2.3). Concentration(${\mu}g/kg$ of other liquous were ; for Pb $7.5\;{\pm}\;5.1$(0~13.7), Cd $5.8\;{\pm}\;3.9$(0.6~11.2), As $25.2\;{\pm}\;39.0$(0.5~103.3), Hg $0.3\;{\pm}\;0.1$(0.1~0.5). The present study showed that difference of the amount of constituent in a same category of food are not affect to the content of heavy metals among them. The residual levels of takju, yakju, sake, beer, fruit wine, soju, whiskey, brandy, general distilled liquor, liquor, other liquors are within the maximum levels, prescribed by Korea food code. It is given that heavy metal exposure of Pb, Cd, As, Hg from consumption of alcoholic beverages (takju, yakju, sake, beer, fruit wine, soju, whiskey, brandy, general distilled liquor, liquor, other liquors) are less than 0.03%, 0.06%, 0.01%, 0.01% (mean) in provisional tolerable weekly intake (PTWI) respectively, indicated by FAO/WHO.

• Microbiology and Biotechnology Letters
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• v.43 no.4
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• pp.378-384
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• 2015

Nuruk is a fermentation agent, which has been used for the production of traditional Korean alcoholic beverages. The objective of this study was to investigate the effects of temperature on nuruk fermentation. One wheat nuruk sample was fermented at $36^{\circ}C$ for 30 days (TN-A) and another at $45^{\circ}C$ for 10 days followed by $36^{\circ}C$ for 20 days (TN-B). The activities of ${\alpha}$-amylase, glucoamylase, and acidic protease, as well as metabolite contents were measured. Initially, the enzymatic activities increased rapidly regardless of the fermentation temperature. After 3 days of fermentation, the enzymatic activities were maintained in TN-A, but gradually decreased in TN-B until the end of fermentation process. Metabolite analysis using $^1H$-NMR showed that the levels of glucose, glycerol, fructose, mannitol, and lactose initially increased quickly and then decreased in TN-A. However, they initially decreased and then were maintained over the fermentation period in TN-B. The contents of glycine, proline, and serine were higher in TN-A than in TN-B. This study suggests that a constant temperature of approximately $36^{\circ}C$ is appropriate for achieving high amylolytic and proteolytic activities in the production of wheat nuruk.

• Food Science and Preservation
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• v.8 no.3
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• pp.326-330
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• 2001

The characteristics of used wine yeast strains were as follows, S6U showed low fermentation speed than those of other yeast strains, but this strain fermented completely later. The wine fermented by W-3 was very low contents of total acid, 0.75% and the ones fermented by UCD530 and AC- contained much extract, 3.26 mg/L and 3.22 mg/L respectively. The wine fermented by CEG and CS2 were predominant in yellowness, and EC1118 produced large amount of acetaldehyde, 49.9 mg/L than those of other strains. EC1118 and CY3079 displayed low methylene blue dyeing ratio, below 15%, meaning high alcohol tolerance yeast. UCD530 produced extremely high contents of glycerol, succinate and lactate compared with other strains. These properties revealed that UCD530 was a typical Saccharomyces bayanus species. The main organic acids produced by wine yeasts were pyruvate, lactate, succinate and acetate. The concentration of acetate in experimental wine could be divided into two parts, one group had concentration below 170 mg/L (UCD530, EC1118, AC-, CY3079, W-3), and the other had concentration up to 350 mg/L (S6U, CEG, CS2).

• Mycobiology
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• v.40 no.2
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• pp.117-123
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• 2012

Nuruk contributes to the unique characteristics of Korean alcoholic beverages. In this study, the effects of nuruk extracts (NE) on anti-oxidant characters, melanogenesis, and anti-photoaging activity were investigated. NEs were obtained from the 70% ethanol extracts of six types of nuruk, which have been used in brewing of fermented alcohol beverages in Korea. First, various antioxidant characteristics were identified in terms of 2,2'-azino-bis(3-ethylbenzthiozoline-6-sulphonic acid) (ABTS) radical scavenging activity, superoxide dismutase (SOD) expression, and inhibition of xanthine oxidase activity. NE#4 exhibited potent ABTS radical scavenging activity ($IC_{50}$ = 19.51 ${\mu}g$/mL). Compared with NE#4, relatively lower levels of activity were observed for NE#3 and NE#6, with $IC_{50}$ values of 90.99 and 76.88 ${\mu}g$/mL, respectively. According to results of western blot analysis for determination of SOD expression in $H_2O_2$-treated HepG2 cells, NE#5 and NE#6 induced a dramatic increase in the expression ratio of SOD, compared to the group treated with $H_2O_2$ only. Activity of xanthine oxidase, which converts xanthine into uric acid, generating superoxide ions, was inhibited by NE#4 and NE#6 in a dose-dependent manner. NE#4 induced significant inhibition of mushroom tyrosinase activity. A reduction in cellular melanin contents of 80% was observed in B16F1 melanocytes treated with NE#5 and NE#6; these effects were similar to those of arbutin at 100 ${\mu}M$. In addition, gelatin zymography and reverse transcription-PCR analysis were performed for assessment of anti-photoaging activity of Nuruk. Treatment with NE#6 resulted in dramatically inhibited activities of matrix metalloproteinase (MMP)-2/-9, suppressed expression of MMP-1, and increased expression of type-1 procollagen. Results of gelatin zymography for NE#4 and NE#5 were similar, to a slightly lesser degree. These results suggest the potential of NE#4 and NE#6 as natural ingredients for use in functional foods and cosmetics.

• Korean Journal of Food Science and Technology
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• v.36 no.1
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• pp.14-18
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• 2004

Analysis methods of artificial sweeteners, aspartame, acesulfame potassium, sodium saccharin, and sucralose isolated from foods were developed using high performance liquid chromatography, HPLC conditions for aspartame, acesulfame potassium, and sodium saccharin were: column, Symmetry $C_{18}(3.9mm\;i.d{\times}150mm,\;5{\mu}m)$; mobile phase, 0.05M sodium phosphate monobasic : acetonitrile (9 : 1, pH 3.5, containing 0.01M tetrapropylammonium hydroxide); detector, UV detector at 210 nm. HPLC condition for sucralose were : column, Symmetry $C_{18}(3.9mm\;i.d{\times}150mm,\;5{\mu}m)$; mobile phase, water:methanol (7 : 3); detector, refractive index detection (sensitivity = 16). Recoveries of artificial sweeteners in foods including soft drinks, fruit and vegetable beverages, alcoholic beverages, fermented milk beverages, soybean milk, ice cream, snacks, chewing gums, jam, honey, kimchi salted food, special dietary products, processed fish products, candies, food additive mixtures, chocolate and cocoa were 76.1-101.3%, 82.3-103.2%, 83.1-103.7%, and 80,6-99.5% for aspartame, acesulfame potassium, sodium saccharin, and sucralose, respectively.

• Microbiology and Biotechnology Letters
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• v.41 no.4
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• pp.442-448
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• 2013

Lactic acid bacteria (LAB) are a representative group of probiotics and used in many fermented foods and beverages. Several recent studies have shown that LAB are present in makgeolli which is a traditional Korean alcoholic beverage. However, most LAB are intolerant of more than 6% (v/v) alcohol concentrations. For this reason, alcohol-tolerant LAB are isolated from kimchi, makgeolli and nuruk using alcohol containing selective media. After being cultured in MRS broth containing 13% (v/v) alcohol, the two strains which showed the highest increasing O.D values, were finally selected. As results of 16S rRNA gene sequencing and biochemical characterization using an API kit, the two species were identified as Pediococcus acidilactici K3 and S1. In addition, the identified two strains produced bacteriocins against Staphylococcus aureus. When compared with the P. acidilactici type strain, the two selected strains possessed two to three time higher growth on 12-13% (v/v) alcohol containing MRS broth. The viability of P. acidilactici K3 and S1 when inoculated in makgeolli and stored at $10^{\circ}C$ did not decrease through a period of one month indicating that the selected strains can be used for LAB containing makgeolli.

• Journal of Society of Preventive Korean Medicine
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• v.18 no.1
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• pp.93-101
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• 2014

Objective : The aim of this study is to analyze medicinal herbs, the ingredients of traditional Korean liquor, focusing on efficacy in the traditional Korean medicine. Through this study, for vitalizing traditional Korean liquor market, the researchers attempt to explain the superiority of traditional Korean liquor and the advantages of using herbs to brew alcoholic beverages. Method : We conducted a research targeting traditional Korean liquors in domestic market from July through september 2012, and finally 70 kinds of liquor were selected and analyzed. Results : Among traditional liquors, fermented liquors are most common. When comparing regions of brewery, the central region of Korea, Gyeonggi-do and Chungcheongnam-do, is major brew area. 37 liquors contain just one medicinal herb. followed 10 liquors contain two medicinal herbs. The most frequently used medicinal herb is Ginseng Radix. And Lycii Fructus, Schisandrae Fructus, Angelicae Gigantis Radix and Chrysanthemi Indici Flos are well used medicinal herbs to brew traditional liquors. In the classification of efficacy of medicinal herbs, tonifying and replenishing medicinal herbs are most popular as ingredients in the traditional alcohols, astringent medicinal herbs, exterior releasing medicinal herbs and heat clearing medicinal herbs are also frequently used. Investigation of tastes and properties of the herbs, it reached a conclusion as below: sweet taste is most common, followed by sour taste and bitter taste. Warm property is account for 50% approximately, followed by cold property. Conclusion : Medicinal herbs have been widely used in the traditional Korean liquor. It came out into the open that the liquor with medicinal herbs is very good for our body in terms of longevity and invigoration. However, liquor consumers concern about not only the efficacy but also the taste, scent and color. Therefore, further study about these things would be required to demonstrate the superiority of the traditional Korean liquor.