• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.1
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• pp.78-89
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• 1994

To evaluate of quality of Yakju brewed with different types of fermenters(Nuruk) and brewed by a method described in Sallymkyungjae, blucoamylase and protease and protease activities of Nuruk were measured, and proximate composition , coloring degree, acetaldehyde , alcohol , , fusel oils , amino acid content , mineral content and sugar composition of Yakju samples were also determined. It was foung that the lower the pH, the lower the glucoamylase acitvity in Nuruk samples A to E . In A, B, D and H, protease activity washigher at ph 5.5 than at pH 5.0 . Yakju sampels 1 to 5 during fermentation , total acidity and amino acid content were high at the first step and were getting lower gradually at the second step. In Yakju samples 6 to 11 , ethanol content was high in 6b, 7b, 8a, 8b and 11b. At the second step, residual sugar content was getting higher gradually in 7 a, 11 a and 11b. The coloring degree of Yakju wasinfluenced by not only color of Nuruk but also Fe content in Yakju . Of the Yakju examined , only 9a and 9b contained acetaldehyde in trace amounts. Thanol content was the highest in 8a and 8b. Fusel oil content was high in 8a and 8b. In samples 6 to 9 , aspartic acid content was higher in treatment a than treatment a than treatment b, but tyrosine , histidine and proline contents were higher in treatment a than treatment b. The levels of frucose, melibiose, sorbitol, and arabinose in Yakju brewed from unsteamed rice were higher than in Yakju brewed from steamed rice. K content was the lowest in 9a and 9b. Na content was higher in treatment a than in treatment a than in treatment b. In only 6a, Ca/P ratio was more than one.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.2
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• pp.301-307
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• 2010

This study evaluates quality of Nuruk, which is a source material of Takju, collected in Daegu and Gyeongbuk and investigates fermentation characteristics of Takju made of it. Totally 7 types of Nuruk were examined and their pH and titratable acidity were 5.4~5.9 and around 0.1%, respectively. Saccharifying activity was high in D, F, G, A and E Nuruk by recording over 300 mg%. Lactic acid bacteria count was the highest in G Nuruk with $3.78\times10^8$ and yeast and total microbe count recorded the highest levels, $3.78\times10^8$ and $3.47\times10^8$, respectively in B Nuruk. When quality characteristics of Takju made of each type of Nuruk were compared, alcohol content was the highest in G Nuruk by recording 19.0% and titratable acidity was 0.44~0.86% in all samples. Hunter's color, brown color and turbidity showed different levels according to types of Nuruk and all lactic acid bacteria, yeast and total microbe counts were the highest in A and E Nuruk. For alcohol components, E and G Nuruk showed high fusel oil content levels and methanol and fusel oil contents of all samples were suitable as standards, respectively. The total organic acid content was the highest in B Nuruk at about 4,000 mg% and it was 2,000 mg% and around 1,000 mg% in A, E, F and G Nuruk and C and D Nuruk, respectively. The content of total free amino acid was the highest in B Nuruk at 3,676 mg% and it was observed to be 1,890, 1,676 and 1,531 mg% in G, E and C Nuruk in that order, respectively. Sensory preference of subjects in their 20s was high overall in G and C Nuruk and that of those in their 40s was high in F and C Nuruk. From all of these results, the types of Nuruk largely affected quality and components of Takju and an appropriate method to consider useful purpose is needed.

• Journal of Food Hygiene and Safety
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• v.4 no.3
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• pp.257-261
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• 1989

In order to evaluate the characteristics and quality of various Korean alcoholic beverage, the higher alcohols profiles were analyzed by gas-chromatography. Total amount of the higher alcohols depended on the type and class of the liquors. Gaschromatographic analysis showed that the type of Gin, Rum and Vodka except for SB contain n-propanol mainly. The amount of the higher alcohols determined was proportional to the content of the originally fermented liquor in the whisky. The difference in the ratio of iso-amyl alcohol content to that of iso-butanol may be useful as a parameter in evaluating the class of the whisky.

• Food Science and Preservation
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• v.18 no.5
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• pp.779-785
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• 2011

This study was conducted to investigate and compare the characteristics of alcohol fermentation in oriental melon by different yeast. As a result, no significant difference in pH, total acidity and sugar content was found in alcohol fermentation of oriental melon by different yeast. The pH was shown to be constantly maintained but the total acidity was shown to increase during fermentation process. The sugar content was rapidly decrease starting from 3 day of fermentation, and it was reduced to be approximately 7 oBrix after fermentation. For organic acid content, lactic and citric acid contents were shown to be the highest in all periods of fermentation, which revealed that lactic and citric acid were major organic acids. Free sugar content were shown to gradually decrease during the fermentation and to be rarely detected at 9 days of fermentation. Alcohol content was shown to be 14.20% at (C) S. cerevisiae RC-212, which was the highest content. It was shown to be more than 12% at other periods, which showed that no significant difference in alcohol content was found according to different yeast. For alcohol components, acetaldehyde content was shown to be the highest at (E) S. cerevisiae K1-V1116, and methanol content was shown to be relatively higher at (C) S. cerevisiae RC-212 and (D) S. bayanus EC-1118. N-propanol, 2-methyl-1-propanol and isoamyl alcohol, which belong to fusel oil, were shown to be produced at 3 day of fermentation and gradually increase. These results, no significant difference in physicochemical properties of alcohol fermentation in oriental melon by different yeast.

• Korean Journal of Food Science and Technology
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• v.31 no.5
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• pp.1330-1336
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• 1999

Effects of clarification and aging of honey wine(mead) and fruit honey wine(melomel) were investigated. Among the clarifiers tested, 'kaki shibu' and 'sake light' were effective in clearing honey wine. Clear honey wine with more than 90% light transmittance was obtained by treatment with $0.05{\sim}0.1%$ of 'kaki shibu' and 'sake light' for 2 days. Higher concentration of these clarifying agents was needed for the clarification of fruit honey wines. Treatment with 0.5% of 'sake light' and $0.05{\sim}0.1%$ of 'kaki shibu' for 4 days was effective for clearing Tangerine honey wine and Japanese apricot honey wine. Though Hunter L-values of honey wines decreased a little bit by using clarifiers, their light transmittance became more than 98% after ultrafiltration. As the content of soluble solid in mash at the beginning of fermentation increased, the content of acetaldehyde, n-propyl alcohol, n-butyl alcohol and iso-amyl alcohol of honey wine increased during aging, while the content of iso-propyl alcohol decreased. During the aging of honey wines, the sensory quality of them became milder as the amount of acetaldehyde and fusel oil decreased. Among more than twenty different volatile flavor components detected from honey wines, 1-phenyl ethyl alcohol, benzyl alcohol, 2-phenyl ethyl alcohol, octacosane and triacotane were identified as the major components for the flavor of honey wines. Sensory evaluation of the honey wines indicated that the melomel made with Japanese apricot was better than the Tangerine melomel in the aspects of taste, flavor, color and the overall acceptability. Tangerine melomel was even inferior to honey wine(mead).

• Korean Journal of Food Science and Technology
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• v.29 no.3
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• pp.555-562
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• 1997

The characteristics of mash qualities of takju prepared by using different nuruk (Korean-style bran koji) such as Mucor racemosus nuruk, Rhizopus japonicus nuruk, Aspergillus oryzae nuruk, Aspergillus kawachii nuruk and traditional nuruk were investigated during fermentation. At the begining of fermentation, ethanol content was in the range of $2.0{\sim}3.0%$. However, it increased to $8.2{\sim}12.6%$ after 16 days of fermentation. Takju made from Rhizopus japonicus nuruk showed higher ethanol content than treated otherwise. pH of takju made from Rhizopus japonicus nuruk showed higher value the others. Total acids were $0.15{\sim}0.20%$ at the begining of fermentation, and it increased to $0.086{\sim}1.57%$ after 16 days of fermentation. Total sugar were $16.64{\sim}17.62%$ at the begining of fermentation, but decreased to below 7.00% after 16 days of fermentation. Rhizopus japonicus nuruk showed the lowest level of total sugar content. Except ethanol, iso-amyl alcohol and iso-butyl alcohol were major part of minor alcohol in the mash of takju. Higher concentration of iso-amyl alcohol, iso-butyl alcohol and n-propyl alcohol were found in the mash of Rhizopus japonicus nuruk whereas the level of phenylethyl alcohol was high in the mash of traditional nuruk. Fusel oil was $0.002{\sim}0.411\;mg/mL$ during fermentation.

• Journal of the Korean Society of Food Culture
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• v.6 no.3
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• pp.251-255
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• 1991

The flavor and organoleptic properties of Hongju prepared by Kokja and Koji method were tested. There was no great difference of total acid in Hongju with different fermentation methods. The alcohol content of Hongju prepared by Koji method was higher than that of Kokja method and methanol content was very little as about $0.02{\sim}0.03$ mg/ml in all samples. The aldehyde content was $7.5{\sim}32$ mg% and fusel oil was higher in Hongju prepared by Koji method than that of Kokja method. As the result of sensory evaluation, new Hongju, S-N prepared by Kokja method with wheat and rice was to be best quality.

• Food Science and Preservation
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• v.15 no.4
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• pp.512-517
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• 2008

Fermentation characteristics of chestnut-added yakju prepared using various proportions of raw materials such as rice koji, rice flour, cornflour koji and cornflour were investigated. The pH of chestnut-added yakju prepared with cornflour koji and saccharified cornflour showed a higher value than that of chestnut-yakju prepared with rice koji and saccharified rice flour. The total acid content of chestnut-added yakju prepared with rice koji and saccharified rice flour was higher than that of chestnut-added yakju prepared using cornflour koji and sacharified cornflour. The reducing of sugar in chestnut-added yakju prepared with saccharified rice flour or saccharified cornflour was rapid at the first brewing stage, decreased dramatically after 2 days, and then decreased slowly after 5 days of fermentation. The value of L and a, the Hunter values, were high in chestnut-added yakju prepared with cornflour koji, and value b was high in chestnut-added yakju with rice koji. The content of iso-amyl alcohol was the highest of seven kinds of fusel oil found in chestnut-added yakju. Ethanol content increased to $17.6{\sim}18.2%$(v/v) after 8 days of fermentation. The content of lactic acid was the highest of all organic acids in the chestnut-added yakju. Sensory test results on chestnut-added yakju prepared with saccharifed corn flour showed that if rice flour is used as a sugar supplement for chestnut, the yakju prepared using koji had better flavor and taste. If cornflour was used in the preparation of chestnut-added yakju, the used of saccharified cornflour offered superior flavor and taste.

• Food Science and Preservation
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• v.7 no.2
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• pp.233-239
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• 2000

To proceed mass production and improve its quality, we fermented potatoes using pilot system and investigated the changes in components during fermentation. After liquefaction and saccharification of potatoes by Nuruk(group I), crude enzyme(group II) and glucoamylase(group III), sugar contents in all groups were 18brix equally. However sugar contents in group(II) and group(III) after 24hrs decreased deeply to 7.2 and 8.8 % respectively, after 24hrs. Alcohol content in group(I) increased slowly and was the highest such as 6.8% after 48hrs. Fusel oils in all groups were n-propanol, isobutanol and isoamylalcohol. The major fusel oil in all groups was isoamylalcohol. At the early stage of fermentation, free sugars were glucose, maltose and lactose. Glucose decreased deeply during fermentation and at latter of the fermentation, galactose was detected in all groups. The contents of total free amino acid were 516.57~569.98 mg% in group(I), 193.97~292.11 mg% in group (II) and 186.31~270.53 mg% in group(III). The contents of aspartic acid, serine, glutamic acid, alanine, arginine, and histidine were high in all groups.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.3
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• pp.443-448
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• 2010

This study investigated alcohol fermentation conditions for preparation of tomato wine. The alcohol contents of tomato wines prepared from semi-mature and full-mature tomato were about 11% whereas that of immature tomato was slightly lower (10.6%). When characteristics of tomato alcohol fermentation were examined on pre-treatment conditions, the wine from full mature-crushed whole tomato contained lower alcohol at 10.6% than those of full mature-crushed tomato removed stem and full mature-tomato juice removed stem (about 11%). For the effect of initial sugar, the alcohol content and sugar content of tomato wine increased in proportion to the concentration of initial sugar (8.8~14.4% and $5.5{\sim}9.2^{\circ}Brix$). However, initial titratable acidity and pH did not affect the alcohol contents during fermentation, and suggesting needed to be supplementation for sensory improvement of tomato wine. When the quality characteristics of tomato wine fermented under these optimal conditions were investigated, alcohol content, sugar content, titratable acidity and pH were found to be 11.1%, $6.1^{\circ}Brix$, 0.68% and 3.7, respectively. For alcohol components, the total amounts of methanol and fusel oil were 346 ppm and 313 ppm. In addition, maltose showed the highest level of 264.6 mg% in the free sugar analysis of tomato wine whereas sucrose contained 18.7 mg%.