• Journal of Microbiology and Biotechnology
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• v.18 no.9
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• pp.1550-1554
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• 2008

A hydrogen sulfide $(H_2S)$ detecting tube was developed for the quantitative determination of $H_2S$ produced by yeast during laboratory scale wine fermentations. The detecting tube consisted of a small transparent plastic tube packed with an $H_2S$-sensitive color-indicating medium. The packed medium changed color, with the color change progressing upward from the bottom of the tube, upon exposure to $H_2S$ produced by yeast during fermentation. A calibration study using a standard $H_2S$ gas showed that the length of the portion that darkened was directly related to the quantity of $H_2S$ (${\mu}g$) with a high correlation coefficient ($r^2$=0.9997). The reproducibility of the $H_2S$ detecting tubes was determined with five repetitive measurements using a standard $H_2S$ solution [5.6${\mu}g$/200 ml (28 ppb)], which resulted in a coefficient of variation of 3.6% at this level of $H_2S$. With the sulfide detecting tubes, the production of $H_2S$ was continuously monitored and quantified from laboratory scale wine fermentations with different yeast strains and with the addition of different levels of elemental sulfur to the grape juice. This sulfide detecting tube technology may allow winemakers to quantitatively measure $H_2S$ produced under different fermentation conditions, which will eventually lead winemakers to better understand the specific factors and conditions for the excessive production of $H_2S$ during wine fermentation in a large production scale.

• Journal of Microbiology and Biotechnology
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• v.22 no.7
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• pp.960-966
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• 2012

The diversity and composition of yeast populations may greatly impact wine quality. This study investigated the yeast microbiota in two different types of wine fermentations: direct inoculation of a commercial starter versus pied de cuve method at an industrial scale. The pied de cuve fermentation entailed growth of the commercial inoculum used in the direct inoculation fermentation for further inoculation of additional fermentations. Yeast isolates were collected from different stages of wine fermentation and identified to the species level using Wallersterin Laboratory nutrient (WLN) agar followed by analysis of the 26S rDNA D1/D2 domain. Genetic characteristics of the Saccharomyces cerevisiae strains were assessed by a rapid PCR-based method, relying on the amplification of interdelta sequences. A total of 412 yeast colonies were obtained from all fermentations and eight different WL morphotypes were observed. Non-Saccharomyces yeast mainly appeared in the grape must and at the early stages of wine fermentation. S. cerevisiae was the dominant yeast species using both fermentation techniques. Seven distinguishing interdelta sequence patterns were found among S. cerevisiae strains, and the inoculated commercial starter, AWRI 796, dominated all stages in both direct inoculation and pied de cuve fermentations. This study revealed that S. cerevisiae was the dominant species and an inoculated starter could dominate fermentations with the pied de cuve method under controlled conditions.

• Applied Biological Chemistry
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• v.47 no.1
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• pp.85-91
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• 2004

In order to improve foxtail millet wine, a traditional Jeju cereal wine, fermentation characteristics of millet Yakju with different types of Nuruks prepared using isolated Aspergillus sp. and Rhizopus sp. were investigated. When the millet wine was brewed with the Nuruk prepared in this study, the combination ratio of wheat flour: barley : wheat bran : millet = 8 : 1 : 1 : 0 (pellet) showed the highest level of alcohol concentration, and a more favorable score than Kuksundang Nuruk in sensory evaluation. The main organic acids in millet wine were lactic and acetic acids, and the minor organic acids were fumaric, oxalic, citric and malic acids. Analysis of sugar compositions showed that glucose, arabinose, and maltose were present in decreasing order, and that xylose was also detected. Flavor components of millet wine were mainly iso-amyl, iso-butyl and n-propyl alcohols. Ethylacetate and acetadehyde were also detected. The contents of iso-butyl and n-propyl alcohols were higher in the millet wine prepared with Kuksundang Nuruk than those prepared with other Nuruks.

• Korean Journal of Agricultural Science
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• v.24 no.2
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• pp.290-297
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• 1997

Danored is considered as the most favorable grape variety for national wine manufacturing in terms of sugar, organic acid contents, annual production amount, as well as quality control convenience after harvest. This study was canied out to know the influence of suspended solid(SS) and skin contact time(SCT) with Danored variety on the white wine quality. The results are summarized as follows; 1. Suspended solid and skin contact time did not greatly influence on the chemical composition of Danored juice. But skin contact time provided slightly increaseness to the content of phenol compounds 2. Suspended solid accelerated fermentation rate of white wine manufacturing. Although the content of suspended solid are less amount than 0.3% in must, wine fermentation was completed to dryness in concentration of sugar. 3. When the content of suspended solid was around 3%, higher alcohol in white wine was increased by the 20%. This result is relatively small increasement compared to the other reported results. 4. Because Danored contained less amount of phenol compounds comparison with other grape varieties, browning capacity in white wine was much favorable to quite low concentration. Especially, phenolic compounds was decreased remarkably as one of fermentation characteristics of Danored variety. 5. As a result of sensory evaluation, wine quality was A-1> B-1> A-2> B-2 in its favorable ranking orders. It was so concluded that A-1 might be the most acceptable one from this study.

• Food Engineering Progress
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• v.13 no.2
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• pp.130-137
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• 2009

This study evaluated the potential of utilizing the osmotic solution from dried mango processing as alternative raw material for mango wine making. Fermentation was carried out using two kinds of yeast strains Saccharomyces bayanus, Lalvin EC-1118 and Saccharomyces cerevisiae, Lalvin D-47 at 20$^{\circ}C$ for 28 days. Physicochemical analysis during fermentation was performed for each treatment and the resulting wine samples were analyzed for color, volatiles and sensory properties. Results of physicochemical analysis between the two fermenting samples as well as the wine samples show almost similar results regardless of the yeast strains. Wine color of sample wines after storage were not significantly different at p<0.05 and when compared with a commercial mango wine. From the volatile analysis, esters and alcohols constituted majority of the compounds. Production of several esters, alcohols, acids and terpenes were affected by yeast strain used in fermentation. Results of sensory analysis showed that wines fermented by S. bayanus EC-1118 strain was more acceptable although sensory scores between the treatments and the reference wine showed significant differences in all the attributes evaluated, except for bitterness. The utilization of osmotic solution from dried mango process could produce similar properties with existing commercial mango wines although there is still need for further work on the improvement of some sensory attributes of the mango wines.

• Korean Journal of Food Science and Technology
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• v.46 no.1
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• pp.33-38
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• 2014

In this study, we investigated the effect of the amount of water added prior to fermentation on the quality of bokbunja (Rubus coreanus Miq.) wine produced. Water was added at 0-fold (A), 1-fold (B), 2-fold (C), 3-fold (D), and 4-fold (E) of the fresh bokbunja weight (w/w), prior to fermentation. Although the amount of bokbunja wine obtained after fermentation increased in proportion to the amount of water added prior to fermentation, the total acidity of the bokbunja wine, adjusted for the weight of bokbunja used in the fermentation process, increased. Moreover, the total phenol and flavonoid content (mg) per weight (g) of bokbunja, in (B), (C), (D), and (E) were 2.86-4.42 and 2.58-3.01 times higher, respectively, than those in (A). These data suggest that different types of bokbunja wines can be produced and different contents of total phenol can be obtained by simply changing the amount of water added prior to fermentation.

• The Korean Journal of Mycology
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• v.16 no.4
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• pp.193-203
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• 1988

The changes of pH, titrable acidity, nitrite and dimethylamine(DAM) content in the various different kinds of the rice wine staters during the fermentation were studied, and the changes of nitrosodimethymaine(NDMA) contents were also determined by High Pressure Liquid Chromatography. After 24hrs, fermentation rice wine starter, pH was generally decreased to below 5 and after full fermentation the acidities were from 0.51 to 0.89 as succinic acid. After 12hrs, fermentation nitrate contents were rapidly decreased. The large amount of nitrite was formed in the beginning of the fermentation. But by the increase in the acidity due to the further fermentation nitrite contents were gradually disappeared. Generally the DMA contents of each rice wine starter were kept unchanged. On completion of fermentation, NDMA contents of starter added with nitrite and DMA were 472.1 ppb. The starter added with DMA was 329.0 ppb, whereas the other added with nitrite was 229.0 ppb, and control without addition of nitrite and DMA was 24.4 ppb. But the rice wine sold in market was not detected any NDMA at all.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.1
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• pp.155-159
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• 2016

The objective of this study was to investigate the effect of fermentation temperature on quality characteristics of apple wine. Apple wine mashes were fermented in 15, 20, and $25^{\circ}C$ water bathes for 9 days. The pH levels of all samples were below 4 from 24 h of fermentation until the end. Total acidities of 0.05% acetic acid solution were 7.8, 7.4, and 7.0% in the 15, 20, and $25^{\circ}C$ fermented samples, respectively. The evaporation of esters generated by combining alcohol and organic acids might be the reason for lower total acidity for high temperature fermentation. Alcohol contents of the 20 and $25^{\circ}C$ fermented samples were 6.5 and 6.6% (v/v), respectively, whereas that of the $15^{\circ}C$ fermented sample was 5.6% (v/v) and significantly lower than the others (P<0.05). Methanol contents were 0.68, 0.82, and 1.69 mg/L in the 15, 20, and $25^{\circ}C$ fermented samples, respectively. Fermentation at higher temperatures generated higher methanol content in apple wine. On the other hand, acetaldehyde contents were 3.43, 2.39, and 1.02 mg/L in the 15, 20, and $25^{\circ}C$ fermented samples, respectively, due to the lower boiling point of acetaldehyde ($20.2^{\circ}C$). Based on the results, a fermentation temperature of $20{\sim}25^{\circ}C$ is effective for apple wine fermentation.

• Food Science and Preservation
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• v.17 no.4
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• pp.547-554
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• 2010

We developed watermelon (Citrullus vulgaris Schrad) wine to increase the market for the fruit, which is currently sold only in fresh form. The pH of watermelon wine was pH 2.8~3.4, the total acid level 0.48~0.55%, and the soluble solid $5{\sim}6^{\circ}brix$ alcohol content was 9.5~10.5%. Fermentation of watermelon juice was satisfactory at both 20C and 25C. All of citric acid, malic acid, and oxalic acid were detected in watermelon wine citric acid was the most abundant. All of glucose, fructose, sucrose, and maltose were present in juice, and both fructose and glucose were used in fermentation. Electron-donating ability (EDA) was high, being 80% of the control value when watermelon wine was diluted to $400\;{\mu}l/ml$. SOD-like activities were present in both watermelon juice and wine, being 55.2% and 49.2% of control values, respectively. Nitrite-scavenging ability (NSA) was 70.2% and 53.2% of control values in undiluted juice and wine, respectively. Watermelon juice showed higher activation than did wine, but functionality neither fell nor rose after fermentation. In sensory evaluation of wine, the overall score was better than average, at 4.15, thus establishing the commercial potential of watermelon wine.

• Journal of Ginseng Research
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• v.31 no.2
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• pp.102-108
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• 2007

The goal of this study was to develop a highly valuable Korean traditional ginseng wine containing various bioactive compounds with good acceptability. The effect of some medicinal plants on the quality and physiological functionality of Korean traditional ginseng wine were investigated. Advanced traditional ginseng wine (AG wine) prepared by addition of 0.5% each Pleuropterus multflorus and Pueraria lobata into the rice mash containing 1% ginseng, 0.4% Fermivin(commercial alcohol fermentation yeast) and Koji (2:1 mixture of nuruk and amylase containing 36 Saccharogenic power per g) showed the highest acceptability and ethanol content (16.8%). Changes of functionalities of the AG wine during fermentation at $25^{\circ}C$ for 30 days were investigated. The highest antihypertensive angiotensin I-converting enzyme inhibitory activity (78.9%) and total acceptability of the AG wine were shown after fermentation at $25^{\circ}C$ for 20 days. However, antioxidant activity, SOD-like activity and fibrinolytic activity of the AG wines were not detected or very low. HMG-CoA reductase inhibitory activity of the AG wine was also shown to be 8.2% and 9.2% after fermentation for 15 days and 20 days, respectively.