• Korean Journal of Food Science and Technology
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• v.42 no.1
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• pp.75-81
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• 2010

In order to investigate the effects of different milling degrees on the quality of glutinous rice wines, the physicochemical properties and volatile compounds of various wines were evaluated. Sample wines prepared from glutinous rice with 90, 80, and 70% milling yields were analyzed for ethanol, pH, total acids, amino acids, soluble solids, coloring degree, UV absorbance, reducing sugars, organic acids, free sugars and volatile compounds. After fermentation for 17 days, ethanol contents in the wines ranged from 15.2 to 15.85%, while total acid levels ranged from 0.31 to 0.35%. The amino acid contents in four samples ranged from 0.63 to 0.73%, while soluble solid contents ranged from 11.4 to $13.1^{\circ}Bx$. The wine prepared from glutinous rice with a 30% degree of milling showed the highest coloring degree, UV absorbance and reducing sugar content among four samples. Furthermore, this wine had the highest levels of malic acid and acetic acid, while the glutinous rice wine prepared from rice with a 0% degree of milling had the highest levels of succinic acid and lactic acid. In all the glutinous rice wines tested, the most abundant free sugar was glucose followed by maltose. With increasing degree of milling, the alcohol, amino acid and organic acid contents of the glutinous rice wines decreased, whereas soluble solids, coloring degree, UV absorbance, reducing sugar and free sugar contents increased. Volatile compounds were identified using GC-MSD, and thirty-nine esters, seven alcohols, six acids, one aldehyde, four alkanes, one alkene and two miscellaneous compounds were identified in the glutinous rice wines. Using relative peak area, it was determined that other than ethyl alcohol, hexadecanoic acid ethyl ester was the major component and was primarily found in the range of 11.566-18.437%. Succinic acid diethyl ester and isoamyl laurate decreased with an increasing degree of milling, whereas hexanoic acid ethyl ester and 2-octenoic acid ethyl ester increased. Overall, it was shown that different milling degrees greatly affected the physicochemical and volatile characteristics of the glutinous rice wines.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.11
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• pp.376-385
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• 2019

This study was undertaken is to isolate brewing yeast suitable for rice beer fermentation from the traditional Nuruk, and to identify the brewing ability of the isolated yeast. After 6 months of research, four brewing yeast isolated from traditional Nuruk showed a normal fermentation pattern in terms of physicochemical data (pH, brix, alcohol content) and higher vitality, as compared to commercial brewing yeast. The concentrations of higher alcohol and ester, that impart the aroma to beer, were 78.4 to 106.5 ppm and 15.1 to 29.3 ppm, respectively. In particular, S. cerevisiae (KCCM 90313) bestowed significantly higher contents of higher alcohol and ester concentrations than rice beer prepared from commercial yeast. We conclude that the four variants of yeast isolated from traditional Nuruk are potentially suitable for manufacturing rice beer. Especially, the S. cevisiae (KCCM 90313) yeast shows excellent yeast activity and aroma production, thereby displaying potential application for manufacturing rice beer in the future.

• The Korean Journal of Food And Nutrition
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• v.6 no.1
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• pp.1-7
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• 1993

19 Samples of koji-starters using in brewing were collected from Korea and Japan, and then 31 strains of koji-molds were isolated from them. After Identification of the Isolate, rice koji was made with each strains, and its saccharogenic activity, dextrogenic activity, proteolytic activity, acid Producing ability, browning reaction and flavor were tested. Among 31 strains of isolates, 10 strains were Identified as Asp nwamori var. kawachii, 18 strains as Asp. oryzae, 3 strains as Asp. usamii mkt. shirousamii. The koji-starters made in Korea were composed of single species of koji-mold with same strain, but those made in Japan were composed of the mixture of different two species or the mixture of different 2 ∼4 strains in same species. Judging from amylolytic and proteolytic ability by species, Asp. awamori var. kawachii H1, I1 and 11, Asp. owsae J2, L2, M2, P3 and P4, and Asp. usamii writ. shirousamii S1 were better than the others. Mold strains isolated from Korean koji-starters were much lower in amylolytic or proteolytic activity than those from Japanese koji-starters. The typical characteristics for the 3 species of koji-molds were that Asp. awamori var. kawachii was strong in acid producing ability, but week in amylolytic and proteolytic ability, that Asp. owzae had strong amylolytic activity and good aroma, but produced little amount of acid, and that Asp. usamii mut. shirousamii had strong Proteolytic activity but some off-flavor.

• Food Science and Preservation
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• v.11 no.2
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• pp.240-245
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• 2004

Chungju(Sambaekju) supplemented with dried persimmon and cordyceps sinensis was prepared and its characteristics were estimated during the brewing. Reducing sugar contents was decreased, ethanol contents was increased in the during fermentation, the final ethanol contents in the first, second and third mash were 5.8%, 11.4% and 16.5%, respectively. Total acidity and amino acidity were increased in the during fermentation. The major organic acid was latic acid, acetic acid, malic acid and succinic acid were a little, and citric acid and tartaric acid were not detected. L-proline(1151.7 mg%) was major in free amino acid. the contents of total and essential amino acid were 11.19% and 217.70 ppm, respectively.

• Microbiology and Biotechnology Letters
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• v.38 no.4
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• pp.373-378
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• 2010

Studies on standardization and quality upgrade of nuruk which is a basic component in brewing are required to increase the quality level of Korean traditional rice wines and to develop the technology for practical use of it. It is important to isolate best strains, to improve the properties and effectively preserve them for brewing industry. In this study, 16 commercial nuruk samples were obtained from the commercial markets located in Chungcheong areas in Korea. 174 fungal strains were isolated from the samples on DG18 medium using a dilution plating method and then screened for enzyme activity and acid production. The active strains were identified based on the morphological characteristics and ITS sequence analysis. Out of 174 strains, 12 strains showed high amylase activity. Especially, Rhizopus sp. CN084, CN174, Aspergillus sp. CN161 and Mycocladus sp. CN042 showed high saccharogenic power and dextrinogenic enzyme activity on cooked wheat bran medium. On the other hand, Aspergillus sp. CN010, CN161, Rhizopus sp. CN105, CN168 and Rhizomucor sp. CN088 produced high acid production on the same medium. Our results showed that the active strains may be used as microbial sources for nuruk starter with good quality in brewing.

• Korean Journal of Food Science and Technology
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• v.54 no.2
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• pp.185-195
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• 2022

To enable the widespread use of buckwheat and create novel consumer demands through improved food processing techniques, we compared the quality characteristics of roasted groats following different processing and brewing methods for common and tartary buckwheat. The various processing steps resulted in significant reductions in rutin content for both buckwheat species, while the quercetin content increased in the tartary buckwheat. The fully processed tea products showed dramatic differences in rutin content, which varied based on the buckwheat species, formulation, and brewing method. Tartary buckwheat contained an average of 61 times more rutin than common buckwheat. The tartary buckwheat variety, Hwanggeum-miso, was used to determine an optimal roasting temperature of 70-80℃. Finally, we suggest that consumers who want buckwheat tea rich in rutin would prefer hand-drip-extracted tea, while those who want tea with less bitterness, sweetness, and good flavor would prefer the cold-brewed method.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.1
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• pp.38-44
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• 1994

The study was conducted to investigate some grain quality characters related with brewing fittness for rice wine by adopting eight rice varieties as materials. Six japonica rice varieties except two Tongil-type rice had short and round grain of 1.80 or lower grain length/width ratio. 1000-grain weight of brown rice was 21.7~29.5g of significant difference among varieties. The white-center of rice grain was most severe in Hidahomare and Iri 402. Among tested varieties, Seomjinbyeo, Iri 402, Dongjinbyeo and Hidahomare had 50% or higher head rice ratio, while the others had relatively worse milling properties resulted from higher ratio of notched-belly and broken grain. Chemical components and total acid and amino acid content of refined rice wine was relatively good in every variety. Liquifying and saccharificating power was higher and koji conditon was also good in the varieties of high head rice ratio. Seomjinbyeo, Dongjinbyeo and Iri 402 was preferred in sensory test of refined wine and was recognized as superior adaptable rice varieties for brewing rice wine.

• Journal of Microbiology and Biotechnology
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• v.20 no.11
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• pp.1539-1545
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• 2010

In beer, glutathione works as the main antioxidant compound, which also correlates with the stability of the beer flavor. In addition, high residual sugars in beer contribute to major nonvolatile components, which are reflected in a high caloric content. Therefore, in this study, the Saccharomyces cerevisiae GSH1 gene encoding glutamylcysteine synthetase and the Saccharomycopsis fibuligera ALP1 gene encoding ${\alpha}$-amylase were coexpressed in industrial brewing yeast strain Y31 targeting the ${\alpha}$-acetolactate synthase (AHAS) gene (ILV2) and alcohol dehydrogenase gene (ADH2), resulting in the new recombinant strain TY3. The glutathione content in the fermentation broth of TY3 increased to 43.83 mg/l as compared with 33.34 mg/l in the fermentation broth of Y31. The recombinant strain showed a high ${\alpha}$-amylase activity and utilized more than 46% of the starch as the sole carbon source after 5 days. European Brewery Convention tube fermentation tests comparing the fermentation broths of TY3 and Y31 showed that the flavor stability index for TY3 was 1.3-fold higher, whereas its residual sugar concentration was 76.8% lower. Owing to the interruption of the ILV2 gene and ADH2 gene, the contents of diacetyl and acetaldehyde as off-flavor compounds were reduced by 56.93% and 31.25%, respectively, when compared with the contents in the Y31 fermentation broth. In addition, since no drug-resistant genes were introduced to the new recombinant strain, it should be more suitable for use in the beer industry, owing to its better flavor stability and other beneficial characteristics.

• Food Science and Preservation
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• v.24 no.5
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• pp.714-724
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• 2017

Soju is a Korean traditional distilled alcoholic beverage produced from mashes various crops and Nuruk which is cultured with wild microorganisms. This study was conducted to investigate rice-Soju brewing characteristics of yeasts isolated from Korean traditional Nuruk. The general components of rice (Hanarumbyeo) raw materials were 14.7 g of water, 6.8 g of crude protein, 0.9 g of crude lipid, 0.4 g of crude ash, and 76.5 g of carbohydrate in 100 g. Saccharifying and proteolytic activities in Hanarumbyeo ipguk (solid-state culture of Aspergillus luchuensis) were also determined. The alcohol content of the fermented wash from isolates was 15.37-16.58% (v/v), which is 16.7-36.0% higher than that of industrial yeasts (12.33-13.19%). Reducing sugar contents were 2.04-3.92 and 7.92-8.78 g/100 mL in the isolates and industrial yeasts, respectively. The isolated yeasts showed 25.2-52.7% higher yield of distillates (41% alcohol) compared to industrial yeasts. Forty-one components were detected in the rice distillated Soju (25% alcohol) and principal component analysis revealed differences between the isolated and industrial yeasts with respect to the contents of i-BuOH, isobutanal diethyl acetal, ethyl caprate, and tetradecanoic acid.

• Korean journal of food and cookery science
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• v.30 no.6
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• pp.746-756
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• 2014

This study investigated the quality characteristics and physiological activities of takju prepared with whole chestnut (15%, 30% and 50% with steamed rice) during fermentation. The pH level began to decrease after the secondary brewing stage. The total acid as well as the organic acid content increased during fermentation. Lactic acid and succinic acid were the main organic acids in takju fermented with whole chestnut. The level of total sugar and reducing sugars in takju fermented with whole chestnut increased at the first brewing stage and then slowly decreased after 4 days of fermentation. Also, the total number of viable cells and microbial populations such as lactic acid bacteria and yeast in the treatments increased to about 108 CFU/mL after 1 days of fermentation and then decreased gradually afterward. The ethanol content in takju fermented with whole chestnut rapidly increased during the initial 4 days of fermentation, to a maximum content of 18.2% after 8 days. The colour values of the treatments did not show any significant differences between 0% and 15% chestnut content. However L value decreased, while the a and b values increased when the whole chestnut content above 30%. The total polyphenol level, electron donating ability, nitrite-scavenging ability and ferrous ion effect also increased as the ratio of whole chestnut increased. Sensory scores of takju fermented with 15% chestnut were greater than those of takju prepared by other treatments.