• Asian-Australasian Journal of Animal Sciences
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• v.15 no.4
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• pp.602-609
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• 2002

Lao-chao is a traditional Chinese fermented rice product with a sweet and fruity flavor, containing high levels of glucose, a little alcohol and milk-clotting characteristics. In order to optimize commercial production of lao-chao, Rhizopus javanicus and Saccharomyces cerevisiae were selected as the mold and yeast starter, respectively. A commercial mixed starter (chiu-yao) was used as control. Fermentation of the experimental combination revealed a sharp drop in pH (to 4.5) on the fourth day, remaining constant thereafter. Content of reducing sugars gradually decreased throughout the entire fermentation period. Of the free amino acids, higher quantities of alanine, leucine, proline, glutamic acid, glutamine and $NH_3$ were noted. For sugars, glucose revealed the highest concentration, while organic acid levels, including those for oxalic, lactic, citric and pyroglutamic acid, increased throughout the fermentation period. Twenty-one compounds were identified by gas chromatography from aroma concentrates of the lao-chao culture filtrate, prepared using the headspace method. For the flavor components, higher quantities of ethanol, fusel oil and ester were determined in both culture filtrates. In regard to the evaluation of yogurt-like product, there were significant differences in alcoholic smell, texture and curd firmness.

• Korean journal of food and cookery science
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• v.6 no.4 s.13
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• pp.59-68
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• 1990

Juices prepared from carrots, apples, and mandarin oranges were fermented with Leuconostoc mesenteroides or along with Saccharomyces cerevisiae. The pH of the fermented juices was not found significantly different between the mixed and single-cultured groups. The juices containing 0.5% NaCl had lower pH than the groups without 0.5% NaCl. The final pH of the single-cultured gruops was the highest among the sample groups. However, reducing sugar content of the mixed-cultured groups was lower than that of the single-cultured groups. The viable cells of the mixed-cutured groups were remarkably increased until 3 days of storage, and after 6 days they were gradually decreased. The results of the sensory evaluation demonstrated acidic, salty and alcoholic flavors were significantly different among the groups. The single-cultured group without salt was significantly more acidic than the non-pasteurized control group. The mixed-cultured group with salt was significantly more alcoholic than the group without salt and control groups. The non-pasteurized control group was significantly more homogeneous than the mixed-cultured groups and single-cultured group with salt. Preference ranking test showed that flavor and overall acceptability of the fermented juices was significantly different among the groups. Flavor of the single-cultured group without salt was found significantly better than those of the groups with salt. With the respect of overall acceptability, the single-cultured group without salt was significantly more acceptable than the non-pasteurized control group and the mixed-cultured group with salt.

• Korean Journal of Food Science and Technology
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• v.49 no.4
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• pp.383-389
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• 2017

This study aimed to select a yeast strain for optimizing the quality of distilled spirits. The brewing and distilling properties of 4 KFRI (Korea Food Research Institute) yeasts (Y88-4, Y98-4, Y172-6, Y192-4) and 2 industry yeasts (C1, C2) were compared. For investigating the possibility of using these strains on an industrial scale, diverse analytical methods were applied to assess parameters associated with distilled spirit quality such as alcohol content, pH, total acidity, and soluble solid content. After 11 days of fermentation, the alcohol strength obtained using six yeast strains reached 13.9-16.4% (v/v), while pH was 3.9-4.0, and total acid was 0.40-0.52%. To compare GC-MSD Volatile flavor components, all the distilled spirit samples were diluted to 20% (v/v) alcohol strength. Seven fusel alcohols, 26 esters, 2 acids, and 3 miscellaneous compounds were detected in the distilled spirits. Y88-4 had the most abundant volatile flavor component and scored the highest overall preference in sensory evaluation. After analyzing the various properties of yeasts, strain Y88-4 was finally selected as the best strain for producing distilled spirits.

• Food Engineering Progress
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• v.14 no.3
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• pp.249-255
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• 2010

Ten commercial activated carbons (ACs) prepared from four different sources (bamboo, wood, peat, and coal) were evaluated for their adsorptive efficiency of six volatile compounds (isoamyl alcohol, hexanal, furfural, ethyl lactate, ethyl octanoate, 2-phenyl ethanol) which were dissolved in a 30% alcoholic model solution. These six volatile compounds are frequently found in alcoholic beverages and possibly contribute to physiological hangover due to their high concentrations. They are also generally regarded as off-flavor compounds at certain levels in alcoholic beverages such as whisky and vodka. Two hundred mL of 30% alcoholic solutions containing these six volatile compounds were treated with 0.2 g of ACs while stirring for 16 hr; the treated solutions were then measured for their adsorptive efficiencies (or removal efficiencies) by gas chromatographic analysis using two different sampling methods (direct liquid injection and headspace-solid phase microextraction). The adsorptive efficiencies of the ACs varied depending on the identity of the volatile compounds and the source material used for making the ACs. Ethyl octanoate, 2-phenyl ethanol, and hexanal were removed at high efficiencies (34-100%), whereas isoamyl alcohol, ethyl lactate, and furfural were removed at low efficiencies (5-13%). AC prepared from bamboo showed a high removal efficiency for isoamyl alcohol, aldehydes (hexanal and furfural), and 2-phenyl ethanol; these major fusel oils have been implicated as congeners responsible for alcohol hangover.

• The Korean Journal of Community Living Science
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• v.23 no.2
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• pp.199-206
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• 2012

In order to evaluate the aroma compounds in Korean traditional alcoholic beverages, volatile compounds of the commercial wines, Makgeolli were analyzed and quantified using the conventional method. Eight volatile compounds including three kinds of alcohols, two kinds of organic acids and three kinds of ether were extracted by Liquid-Liquid Extraction with Dichloromethane. For the separation and quantification, Gas chromatography coupled with mass spectrometry (GC/MS) was used to analyze these compounds. Also, the separation efficiency of these compounds was performed and compared with GC column. The results of this study were as follows ; Eight kinds of volatile compounds were separated well on the HP-88 column better than on the DB-5MS column. Short chain fatty acids, butyric acid and isovaleric acid were not detected in two brands of makgeolli samples. The higher alcohols were detected in the range of 0.86~225.68 ${\mu}g/mL$ and ethyl esters were detected in the range of 0.86~225.68 ${\mu}g/mL$, respectively. There compounds are known to be associated with sensory and odorant.

• The Korean Journal of Food And Nutrition
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• v.26 no.3
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• pp.553-564
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• 2013

The core ingredient of traditional Korean style soy sauce is soy bean without any wheat or rice incorporated. National brands as well as regional micro-brewed companies constitute the soy sauce market in Korea. The present study investigated the physico-chemical and sensory properties of soy sauces produced by small-scale or mass-production. Additionally, the key physico-chemical parameters sufficiently representing the critical sensory characteristics have been identified. Ten types of soy sauce brewed by the Korean traditional method were selected for the study. Among these samples, seven types were brewed in small-scales in the Gyeonggi-do region whereas the other 3 types were mass-production products of major national brands. The total solid, reducing sugar, salinity, sugar content, amino nitrogen, CIELAB, acidity, and pH of soy sauce samples were measured for the physico-chemical analysis. A generic descriptive analysis was conducted to analyze the sensory characteristics of the samples using six trained panelists. The descriptive panel developed 21 sensory attributes. The data were statistically analyzed using ANOVA, PCA and PLSR. Overall, the micro-brewed products showed significantly higher value of salinity and acidity but lower content of reducing sugar than the mass-production products. The micro-brewed soy sauces elicited stronger fermented flavor, sourness, and bitterness whereas the national brand products elicited stronger alcoholic odor, sweetness and umami taste. Sugar content, acidity, and amino nitrogen showed strong relationships with fish sauce flavor, umami taste, and rich flavor. Salinity was closely related to the overall flavor intensity.

• Food Science and Biotechnology
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• v.18 no.5
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• pp.1132-1137
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• 2009

Successive application of Saccharomyces cerevisiae DSM 70424 and Saccharomyces rouxii DSM 2535 or DSM 2531 in the production of non-alcoholic beer was investigated. The aim of the study was to consider the impact of the 2 mentioned strains of S. rouxii on the reduction of alcohol content in wort fermented at 12 or $24^{\circ}C$ for 96 hr, applying periodic aeration. The 2 S. rouxii strains were added at the $48^{th}$ hr of fermentation after thermal inactivation of S. cerevisiae cells. The greatest alcohol decrease rate was observed for the treatment containing S. rouxii DSM 2535-fermented at $24^{\circ}C$ (from 1.56 to 0.36%). The concentration of acetaldehyde, diacetyl, and 2,3-pentandione, that have a key role in appearance of 'wort' and 'buttery' off flavors, were significantly lower in S. rouxii-containing treatments fermented at $24^{\circ}C$. S. rouxii-containing treatment fermented at $24^{\circ}C$ showed slightly lower overall flavor acceptability compared to S. cerevisiae-containing treatment fermented at the same temperature. Such score was improved for the products obtained at $12^{\circ}C$.

• Korean Journal of Food Science and Technology
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• v.30 no.3
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• pp.535-541
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• 1998

The soluble solid of red pepper extracted by water was evaluated with descriptive analysis by 10 trained sensory subjects. In the result of the sensory evaluation, the character notes on the flavor of soluble solid were expressed as pungency, sweet, fresh sour, bitter, alcoholic, meaty, chalkiness and astringent. The score of redness was the highest at $4^{\circ}C$ and decreased after 2 hr at $90^{\circ}C$ and the score of sensory pungency was more than 50 and was especially higher at $40^{\circ}C\;and\;90^{\circ}C$. Principal component analysis of the mean ratings showed that kochoojang (fermented red pepper paste) and chigae (meat and vegetable stew) differed from kimchi (unfermented kimchi) and that they had unique sensory attributes. The first two principal components could be explained by 51% of all the components and the taste of soluble solid at $40^{\circ}C$ was highly correlated with sensory attributes such as meaty, fresh sour and sweet and that at $4^{\circ}C$ was chiefly correlated with color components and the taste of soluble solid at $60^{\circ}C$ was showed close relation to astringent, alcoholic and pungency.

• Microbiology and Biotechnology Letters
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• v.38 no.1
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• pp.46-52
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• 2010

Yakju, a Korean traditional alcoholic beverage, is made from glutinous-rice flour or rice starch with nuruk. In this study, we investigated that fermentation characteristics in yakju was made with glutinous rice and pretreatment. The yeast and nuruk were used Y90-9 and SP1800 (a kind of improved nuruk), respectively. pH and brix degree of yakju, brewed with glutinous rice flour by heating, were higher than the others during fermentation process. Total acid contents were 0.2~0.3 and the highest alcohol degree (15.75%(v/v)) was fermented glutinous rice flour by heating. Reducing sugar contents were 3.5-3.9 mg/mL. Yakju, which brewed with glutinous rice flour, of amino acid degree, UV absorbance and color degree was higher than yakju which brewed with glutinous rice starch. Succinic acid was the highest organic acid among 6 organic acids and free sugar contents described as glucose > maltose > fructose. Twenty one components were identified including 3 alcohols, 17 esters and one aldehyde. Of these, ethyl palmitate, which was described as mild flavor, was the highest %area except ethyl alcohol. Overall, the fermentation performed using glutinous rice flour by heating and improved-nuruk showed the best results for yakju production.

• Korean Journal of Food Science and Technology
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• v.49 no.4
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• pp.369-376
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• 2017

Maturation of distilled spirit can generate diverse flavors and tastes. Rice Soju was matured in oak casks (MSO) and stainless steel containers (MSS) for one year at ambient temperature. Ipguk (Aspergillus luchuensis) and Saccharomyces cerevisiae Y88-4 were used, and reduced pressure ($110{\pm}20Torr$) distillation was applied to brew Soju. Acidity and conductivity were increased in both MSO and MSS. MSO reduced alcohol content (from 43 to 40%) and volume (from 18,000 to 12,730 mL), and significantly altered yellowness (from 0.2 to 30.2). Furthermore, MSO increased the isoamyl alcohol (from 276.7 to $339.2{\mu}g/mL$) and isobutyl alcohol (from 122.3 to $144.2{\mu}g/mL$) content. Gas chromatography-mass spectrometry was used to detect volatile compounds in Soju, which included 20 esters, 7 alcohols, 2 acids, and 5 miscellaneous compounds. Oak lactone was detected only in MSO and was considered as a specific flavor component associated with oak maturation. Thus, maturation materials contribute to the physicochemical property of distilled spirits.