• 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 Poultry Science
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• v.33 no.3
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• pp.195-202
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• 2006

Two experiments were conducted to investigate the effect of dietary selenium sources on performance and selenium retention in broiler chickens and laying hens. In experiment 1, the effects of dietary selenium sources and levels on the weight gain, feed intake, feed conversion, and selenium retention of meat in broiler chickens were investigated. for each growth phase, the basal diet was supplemented with 0 (control), 0.12 and 0.24 ppm Se from sodium selenite (SS) and 0.12, 0.24 and 0.60 ppm Se from selenium yeast(SY). Weight gain was significantly increased(P<0.05) in supplemental 0.24 and 0.60 ppm SY compared to the 0.24 ppm SS by diet during day 1 to 35, but feed intake and feed conversion were not affected by the source or the level of Se. Selenium concentrations of breast and leg muscle were significantly increased(P<0.05) in supplemental SS and SY compared to the control, and linearly increased(P<0.05) as dietary. Se level increased by SY, but there was no difference in supplemental 0.12 ppm SS compared to 0.24 ppm SS. In experiment 2, 12-week-experiment using Hy-Line laying hens(31 wk of age) was conducted to compare the effects of selenium sources and levels on egg production, egg weight, daily egg mass, feed intake, feed conversion, egg quality, and selenium retention of egg in laying hens. A corn-soybean meal basal diet was supplemented with 0 (control), 0.06 and 0.12 ppm Se from sodium selenite (SS) and 0.06, 0.12 and 0.30 ppm Se from selenium yeast(SY). Feed conversion was significantly improved(P<0.05) in supplemental 0.06 ppm SS compared to the control, but egg production, egg weight, daily egg mass, and feed intake were not affected by source and level of Se. Haugh unit was not affected by source or level of Se. Yolk color was significantly(P<0.05) higher in supplemental 0.3 ppm SY compared to the control and other supplement in week 12. Eggshell breaking strength was significantly(P<0.05) higher in supplemental 0.06 ppm SY(P<0.05). Thickness of eggshell was not affected by source or level of Se. Se concentrations of egg was significantly improved(P<0.05) in supplemental SS and SY compared to the control, and was significantly increased(P<0.05) as dietary Se level increased by SS and SY, especially SY more effective compared to the SS.

• Journal of Microbiology and Biotechnology
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• v.1 no.3
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• pp.157-162
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• 1991

Conditions for glutathione production in E. coli cells which possess pGH501 (2 gshI+gshII) were studied. In terms of ATP supply for the glutathione synthesis, two different systems have been constructed and compared. When the acetate kinase reaction of E. coli was used for ATP generation, 20 mM of L-cysteine was completely converted to glutathione by toluene-treated E. coli cells (100 mg/ml) harboring pGH501 within 2 h at $37^{\circ}C$. However, considering the economical aspects, the glycolytic pathway of yeast was chosen as a better system for ATP generation. The optimal concentrations of reactants for glutathione production were determined to be as follows; 80 mM L-glutamate, 20 mM L-cysteine, 20 mM glycine, 20 mM $MgCl_2$, 50 mM potassium phosphate buffer (pH 7.5), 400 mM glucose, polyoxyethylene stearylamine ($5\;\mul/ml$), toluene-treated E. coli HB101/pGH501 (100 mg/ml), and dried yeast cells (400 mg/ml). The conversion ratio of L-cysteine to glutathione was 80% (about 5 mg/ml) under optimal condition within 6 h at $37^{\circ}C$.

• Journal of the FoodService Safety
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• v.4 no.1
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• pp.21-28
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• 2023

Saccharomyces cerevisiae and Zygosaccharomyces rouxii are known to produce alcohol in gochujang. To reduce alcohol production, garlic and chives were applied to gochujang solution to find their inhibitory effect on S. cerevisiae and Z. rouxii. The 70% ethanol extract of garlic and chives showed significant inhibition activity against S. cerevisiae and Z. rouxii, showing growth inhibition zone of 14.00±0.00~25.33±0.58 mm by disc diffusion method. In addition, the addition of 70% ethanol extract of garlic and chives in 10% gochujang solution spiked with S. cerevisiae and Z. rouxii reduced the numbers of total aerobic bacteria (below 7 Log CFU/g) and yeast (below 4 Log CFU/g), alcohol content (below 0.30%), respectively. In conclusion, the addition of garlic ethanol (70%) extract or chives ethanol (70%) extract to gochujang inhibited the growth of S. cerevisiae and Z. rouxii, resulting in reduced alcohol content in gochujang. For further study, it is necessary to conduct food application experiments by using real gochujang paste.

• Microbiology and Biotechnology Letters
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• v.52 no.1
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• pp.37-43
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• 2024

Recently, as the interest in makgeolli has increased and its products have become more diverse, the need to analyze the flavor of makgeolli has emerged. In this study, we analyzed the volatile flavor components in commercial makgeolli using an electronic nose. Discrimination function analysis suggested differences in flavor characteristics of commercial makgeolli depending on sterilization and type of fermentation starter. According to the variable importance point scores determined by partial least squares-discriminant analysis, it was revealed that sterilization, nuruk, and yeast profoundly influence the contents of ethyl acetate (fruity scent), acetaldehyde (strong odor) and isoamyl acetate (fruity scent), respectively. This result is expected to be a valuable stepstone to the characterization of makgeolli.

• Preventive Nutrition and Food Science
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• v.14 no.2
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• pp.102-108
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• 2009

The comparative immunomodulatory effects of ${\beta}$-glucans isolated from mushroom fungi (Coriolus versicol), yeast (Saccharomyces cerevisiae) and bacteria (Agrobacterium) on the major functions of macrophages were evaluated. As parameters of macrophage functions, we examined tumoricidal activity, phagocytosis, nitric oxide (NO) production, and the induction of inducible NO synthetase (iNOS) in RAW264.7 cells, following treatments with ${\beta}$-glucans from the three different sources. The results indicated that all ${\beta}$-glucan treatments significantly induced tumoricidal activity in the RAW264.7 cells, with a remarkable effect shown by the beta-glucan from Agrobacterium at a concentration of $10{\mu}g/mL$. There was also a significant increase in iNOS-NO system activity in macrophages treated with ${\beta}$-glucans extracted from yeast; however, iNOS-NO system activity was not markedly changed by the treatment of ${\beta}$-glucans from C. versicolor mushroom fungi or Agrobacterium. Furthermore, the ${\beta}$-glucans from C. versicolor had a significant phagocytotic effect at concentrations of 1, 10, and $100{\mu}g/mL$. Taken together, the present data suggest that these ${\beta}$-glucans, isolated from three different sources, have different effects on macrophage function, and therefore, may have different clinical uses in different for various types of diseases.

• The Korean Journal of Mycology
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• v.42 no.1
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• pp.21-27
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• 2014

Several kinds of yeasts from fruits and flowers of orchard in Yesan-gun of Chungcheongnam-do, Korea were isolated and identified by comparison of nucleotide sequences for PCR-amplified D1/D2 region of 26S rDNA using BLAST. Fourty eight yeast strains of twenty five species and one hundred eight yeast strains of fourty eight species were isolated from fruits and flowers of orchard in Sinam-myeon of Yesan-gun, Chungcheongnam-do, respectively. Among total one hundred fifty-six yeast strains, only sixteen species were overlapped from fruits and flowers.

• The Korean Journal of Mycology
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• v.42 no.1
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• pp.28-33
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• 2014

Various yeasts from wild flowers of Ulleungdo in Gyeongsangbuk-do and Yokjido in Gyeongsangnam-do, Korea were isolated and identified by comparison of nucleotide sequences for PCR-amplified D1/D2 region of 26S rDNA using BLAST. Forty eight yeast strains of twenty two species and sixty yeast strains of twenty five species were isolated from wild flowers of Ulleungdo and Yokjido, respectively. Only seven species were overlapped from the two different islands areas: Cryptococcus albidus, Cryptococcus laurentii, Metschnikowia reukafii, Pichia scolyti, Rhodotorula glutinis, Rhodotorula graminis and Rhodotorula mucilaginosa. Among forty species from two different islands, other thirty three species were restricted to specific collection site suggesting that each area has distinctive yeast flora.

• Journal of Microbiology and Biotechnology
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• v.20 no.2
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• pp.356-362
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• 2010

Ceramide is important not only for the maintenance of the barrier function of the skin but also for the water-binding capacity of the stratum corneum. Although the exact role of ceramide in the human skin is not fully understood, ceramide has become a widely used ingredient in cosmetic and pharmaceutical industries. Compared with other microorganisms, yeast is more suitable for the production of ceramide because yeast grows fast and is non-toxic. However, production of ceramide from yeast has not been widely studied and most work in this area has been carried out using Saccharomyces cerevisiae. Regulating the genes that are involved in sphingolipid synthesis is necessary to increase ceramide production. In this study, we investigated the effect of the genes involved in the synthesis of ceramide, lcb1, lcb2, tsc10, lac1, lag1, and sur2, on ceramide production levels. The genes were cloned into pYES2 high copy number vectors. S. cerevisiae was cultivated on YPDG medium at $30^{\circ}C$. Ceramide was purified from the cell extracts by solvent extraction and the ceramide content was analyzed by HPLC using ELSD. The maximum production of ceramide (9.8 mg ceramide/g cell) was obtained when the tsc10 gene was amplified by the pYES2 vector. Real-time RT-PCR analysis showed that the increase in ceramide content was proportional to the increase in the tsc10 gene expression level, which was 4.56 times higher than that of the control strain.

• Korean Journal of Pharmacognosy
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• v.37 no.1 s.144
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• pp.21-27
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• 2006

Yeast based estrogenicity assay is the simplest and useful for the assay and the discovery of novel estrogenic substances in natural specimens, The estrogen receptor(ER) modulation activity of 50% EtOH extracts of 101 traditional medicinal herbs was assessed using a recombinant yeast assay system with both a human estrogen receptor expression plasmid and a receptor plasmid. Among them, 14 species proved to be active. Pureariae Flos (flower of Puerraria thunbergiana BENTH.) had the highest estrogenic relative potency$(7.75{\times}10^{-3})$ $(EC_{50}=9.39\;{\mu}g/ml)$. The $EC_{50}$ value of $17{\beta}-estradiol$ used as the positive control was $0.073\;{\mu}g/ml)$ (Relative Potency=1.00). There results demonstrated that some of the traditional medical herb may be useful in the therapy of estrogen replacement.