• Journal of the Korean Society of Food Science and Nutrition
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• 제39권9호
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• pp.1366-1372
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• 2010

This study investigated the quality characteristics of brown rice vinegar (agitated culture and static culture) derived from brown rice Takju with different types of yeasts. The alcohol content by yeast was the highest in B (brown rice Takju produced by S. cerevisiae GRJ) at 14.3% and the titratable acidity was less than 0.6% in all ranges. When quality characteristics of agitated and static culture brown rice vinegar using them were compared, acidity of agitated culture vinegar recorded the highest level or 6.05% at 7 day of fermentation DV (brown rice vinegar produced by S. kluyveri DJ97) with the initial acidity of 1.0% and the initial pH of 3.9~4.0, and AV (brown rice vinegar produced by S. cerevisiae JK99), CV (brown rice vinegar produced by S. cerevisiae H9) and BV (brown rice vinegar produced by S. cerevisiae GRJ) recorded as 5.64, 5.55 and 5.32%, respectively. In addition, acidity of static culture vinegar increased continuously to 5.01~5.31% until the 14 day of fermentation and then tended to decrease slightly from the 16 day of fermentation. Difference in acidity and pH of brown rice vinegar according to types of yeast was not significant. Comparison of free amino acid of brown rice vinegar showed that for agitated culture brown rice vinegar, the content of total free amino acid was higher in the order of BV, DV, AV and CV and the content of essential amino acid was the highest in BV by recording over 1,000 ppm. The content of total free amino acid of static culture brown rice vinegar was higher than that of agitated culture vinegar in all ranges and especially static culture brown rice vinegar contained more serine, alanine, valine, isoleucine, leucine and $\gamma$-aminobutyric acid than agitated culture vinegar. In particular, $\gamma$-aminobutyric acid recorded over ten times higher level or 456.91~522.66 ppm. From these results, quality characteristics of brown rice vinegar was affected by acetic acid fermentation methods rather than types of yeast. However, as future aging process is expected to change flavor components and sensory characteristics, studies on various quality factors of vinegar are needed.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제19권9호
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• pp.206-214
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• 2018

This study was conducted from August 2017 to May 2018. Beer was prepared by different ratio of rice and malt and different types of beer, and quality analysis were conducted. The ratio of rice and malt was divided into 0:100 (S0), 20:80 (S1), 40:60 (S2), 60:40 (S3) and 80:20 respectively. We compared the characteristics of the mashing methods(infusion and decoction method) and investigated the characteristics of different types of beer (lager, ale, wheat beer) using yeast (bottom and top yeast). Even with different ratios of rice and malt, normal infusion time was observed and the iodine test was confirmed to be normal. Also, the mashing proceeded normally and the sugar content of the primary wort was between $21.0{\sim}21^{\circ}brix$. In mashing method, the mash concentration, color and flavor of wort were the highest in the three mash method(decoction method). During the fermentation period of beer, the sugar content, pH and yeast number did not differ significantly depending on the ratio of rice and malt, and the type of yeast. Higher alcohol and esters also had no correlation with the ratio of rice to malt, and wheat beer was somewhat higher. The higher the ratio of rice, the more the color intensity(EBC) decreased, the bitter unit(BU) and the preference decreased. When the rice ratio was higher than the malt rate, the degree of preference decreased significantly. Based on the results of this study, it is expected that the rice ratio will be less than the malt ratio and the flavor of the wort will be improved by using the deccoction method. If the malt is supplemented with the use of the special malt and the various hops according to the beer type, it may be helpful to manufacture rice beer.

• Journal of the Korean Society of Food Science and Nutrition
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• 제39권12호
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• pp.1860-1866
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• 2010

The purpose of this research was to characterize physicochemical properties and sensory evaluation of schizandra wines fermented by the yeasts, Sacchromyces cerevisiae SH8094 (S. cerevisiae SH8094) and Sacchromyces cerevisiae SH2855 (S. cerevisiae SH2855) isolated from schizandra fruits and stems and compare these results with the results from commercial activated yeast (Lalvin 1118) and a commercial schizandra wine. Three different schizandra wines fermented by S. cerevisiae SH8094, S. cerevisiae SH2855, and Lalvin 1118 showed similar results in pH and titratable acidity. On the other hand, the schizandra wines fermented by S. cerevisiae SH8094 and S. cerevisiae SH2855 showed high brix ($14^{\circ}$brix), low alcohol content (9%), and low yeasts count (4.1 log CFU/mL), compared with the schizandra wine fermented by Lalvin 1118. Both schizandra wines made with S. cerevisiae SH8094 and S. cerevisiae SH2855 showed higher scores in swallowing and overall acceptability than the schizandra wine made with Lalvin 1118. When compared with a commercial schizandra wine, the schizandra wine fermented with S. cerevisiae SH8094 showed better qualities in aroma ($6.65{\pm}1.47$), color ($7.53{\pm}1.14$), and overall acceptability ($6.76{\pm}1.03$). In conclusion, S. cerevisiae SH8094 which was isolated from schizandra fruits and stems has a high potential in schizandra wine fermentation.

• Microbiology and Biotechnology Letters
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• 제9권2호
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• pp.83-89
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• 1981

Several kinds of organic acids, alcohols, aromatic compounds and sugars as carbon sources were tested in order to produce the cell mass of Rhizopus oryzae which is used in part of food processing or organic acid fermentation. Sodium acetate among them was good enough for carbon source as well as glucose under the concentration of one percent. All nitrogenous substances tested such as ammonium, nitrate or organic nitrogen compounds were well used by this strain of Rhizopus oryzae as nitrogen source. Ammonium sulfate among inorganic nitrogen compounds was most utilized as a nitrogen source in glucose or acetate medium. This strain did not require any growth factors such as yeast extract. The following composition of medium was therefore determined in order to produce the cell mass of Rhizopus oryzae: Na-acetate 1 %, (NH$_4$)$_2$SO$_4$ 0.2%, $K_2$HPO$_4$ 0.05%, MgSO$_4$.7$H_2O$ 0.01%, NaCl 0.01% (PH 5.5). The cell wall of mycelium grown in above medium was lysed optimally at pH 6.5 and 5$0^{\circ}C$ by the action of Strepzyme 115-5. On producing protoplast from mycelium by enzymatic action, almost all of the mycelium was damaged after 4hrs of treatment.

• Food Science and Preservation
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• 제17권1호
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• pp.23-29
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• 2010

The effects of vinegar, alcohol, and vitamin C on the color, microorganism count, volatile flavor components, free sugar level, free amino acid concentration, and free fatty acid level of minced ginger were investigated during storage for 17 weeks at $10^{\circ}C,\;20^{\circ}C\;or\;30^{\circ}C$. Bacterial levels remained unchanged during storage and mold was not initially detected. Yeast levels in minced ginger were $5{\times}10^1$ CFU/g initially, and yeast was not detected after 2 weeks. The color values increased during storage at high temperature. The volatile flavor component levels decreased during high-temperature storage. The free sugars of minced ginger were glucose, sucrose, and fructose. Sugar levels did not vary greatly with storage temperature. Free amino acid content decreased during high-temperature storage, and glutamine, valine, alanine, asparagine, tyrosine, and leucine were detected. Free fatty acid content increased during storage and the ratio of unsaturated to saturated fatty acids was 3:7.

• Journal of the Korean Society of Food Science and Nutrition
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• 제42권10호
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• pp.1682-1689
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• 2013

The objective of the present study is to elucidate the physicochemical and microbial properties of Korean traditional rice wine, Makgeolli, supplemented with mulberry during the fermentation process. Four hundred grams of mulberries (20% of the total amount of rice) were ground and incorporated into the rice solution (3.5 L of distilled water, 2.0 kg of rice, 28.0 g of yeast, and 80.0 g of nuruk). The rice solution was then placed in a water bath set at $28^{\circ}C$ and left to ferment for 7 days. The alcohol contents between the control and mulberry Makgeolli were not significantly different. The pH values of the control and mulberry Makgeolli decreased and the total acidity values were elevated after a 7-day fermentation. In the microbial analysis, the total viable cell count, lactic acid bacteria count and yeast count increased considerably through the 7-day fermentation process. For all the samples, the glucose and succinic acid contents were highest among all free sugars and organic acids, respectively. Forty-eight different volatile compounds were found in all the samples after the 7-day fermentation process.

• The Korean Journal of Mycology
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• 제40권4호
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• pp.210-214
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• 2012

The aim of this study was to determine changes of physicochemical properties and microorganisms of commercial Makgeolli during storage at $10^{\circ}C$ and $25^{\circ}C$ During storage at $10^{\circ}C$ for 11 days, ethanol contents did not increased up to 7.0%, and pH and total acidity were ranged with 3.12-3.99 and 0.22-0.28%, respectively. Makgeolli which was storaged at $25^{\circ}C$ for 11 days showed more than 7.0% of alcohol contents, pH of 3.96-4.17 and total acidity of 0.27-0.30%. Yeast cell counts showed maximal $2.90-16.00{\times}10^7$ CFU/mL at $10^{\circ}C$ for 3 days and $1.12-29.40{\times}10^7$ CFU/mL at $25^{\circ}C$ for 1 day. Lactic acid bacteria and total bacteria cell counts of Makgeolli which was storaged at $25^{\circ}C$ for 11 days were higher than those $10^{\circ}C$ storage. In preference test, Makgeolli from storage at $10^{\circ}C$ for 11 days was showed the level of 4.9-5.2 points however, Makgeolli from storage at $25^{\circ}C$ for one day showed below 5.0 point.

• Korean Journal of Microbiology
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• 제44권3호
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• pp.264-269
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• 2008

To develop an amylolytic industrial yeast strain producing $\beta$-amylase, the BAMY gene encoding Achlya bisexualis $\beta$-amylase was constitutively expressed under the control of the alcohol dehydrogenase gene promoter (ADC1p) in an industrial strain of Saccharomyces cerevisiae. Yeast transformation was carried out by an integration system containing $\delta$-sequences as the recombination site. The integrative cassette devoid of bacterial DNA sequences was constructed that contains the BAMY gene and $\delta$-sequences. Industrial S. cerevisiae transformed with this integrative cassette secreted 45 kDa $\beta$-amylase into the culture medium. The $\beta$-amylase activity of the transformant was approximately 18.5-times higher than that of A. bisexualis. The multi-integrated BAMY genes in the transform ant were stable after 100 generations of growth in nonselective medium. Hydrolysis of soluble starch and various starches with the enzyme released maltose but not glucose or oligosaccharides.

• Korean Journal of Environmental Biology
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• 제27권2호
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• pp.198-204
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• 2009

From leaf mold and reclamation site soil of the Capital area of Korea, 3 poly(butylene succinate-co-butylene adipate: PBSA)-degrading strains were isolated through the clear zone test. The PBSA-degrading activities of the strains were assessed by means of a modified Sturm test using 0.01% of PBSA film as a sole carbon source. After the modified Sturm tests for 40 days at the respective isolation temperatures, the 3 strains degraded 30%, 55% and 43% of PBSA, respectively. The isolated strains were identified to be Burkholderia cepacia PBSA-4, Bacillus licheniformisPBSA-5 and Burkholderia sp. PBSA-6 through the 16S rDNA gene sequence analysis. Among them, PBSA-5 degraded both PBSA and Poly(vinyl alcohol). The degradation activity of the PBSA degrading strains appeared to be high at moderate temperatures such as $27^{\circ}C$ and $37^{\circ}C$, and initial inoculum size of $10^{10}cfu\;mL^{-1}$ degraded PBSA 1.2~1.3 more times than that $10^9cfu\;mL^{-1}$. Addition of 0.1 or 0.5% (w/w) of gelatin, yeast extract and ammonium sulfate raised the PBSA degrading activity, and especially addition of 0.1% (w/w) of gelatin enhanced the PBSA degrading activity by more than 33%. The mixed strains degraded PBSA faster than the single strain.

• The Korean Journal of Mycology
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• 제44권4호
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• pp.307-313
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• 2016

To develop a functional strawberry Makgeolli, we produced Makgeolli using strawberry as an additive and then investigated its physicochemical properties. Among 7 different alcohol-fermenting yeasts, Saccharomyces cerevisiae JSK104 produced 17.4% ethanol on the 7th day of fermentation and was selected for use in the brewing of strawberry Makgeolli. Changes in physicochemical properties, numbers of yeast and lactic acid bacteria, and antihypertensive angiotensin-converting enzyme inhibitory activity were investigated during the fermentation of strawberry Makgeolli. The pH tended to decrease and the total acidity increased as the fermentation period elapsed. The ethanol content reached about 17% on the 7th day after fermentation, and the numbers of yeast and lactic acid bacteria reached a maximum on the 1st day of fermentation and then maintained a constant number. The antihypertensive angiotensin-converting enzyme activity reached a maximum after 5 days of fermentation and then was not significantly changed afterwards.