• Journal of the Korean Society of Food Culture
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• v.30 no.4
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• pp.475-480
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• 2015

Jeju citrus, which contains an abundance of calcium and vitamin, was used to develop fermented citrus peel extract. A total of seven probiotic strains were applied to tangerine dermis to select the best growing bacteria in citrus peel extracts. B. longum, B. bifidum, and L. mesenteroides were found to grow best in citrus peel extract culture containing glucose, yeast extracts, peptone, and potassium phosphate. Citrus peel extract culture consisting of 1% yeast extract, 5% peptone, and 0.1% phosphate was the best environment for growth of probiotics. The pH, acidity, and viable cell numbers of these fermented extracts were measured. The initial pH level of fermented extracts with nutrients was 5.25 and dropped rapidly to 3.39 after 72 hours of fermentation. The acidity of fermented extracts increased to 4.08 % after 72 hours of fermentation, and the viable cell number in fermented extracts after refrigeration for 2 weeks was $1.3{\times}10^{10}CFU/mL$. The antimicrobial activity of citrus peel fermented extracts against Campylobacter jejuni was determined, and concentrations more than 25,000 ppm showed antimicrobial activity.

• 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.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.3
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• pp.461-466
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• 2010

A cylindrical UV sterilization system was developed to decrease microorganisms in centrifuged Takju (CT). CT was run through 110 strips of honey comb type-teflon tubes and 9 UV lamps (1395 W) were equipped between teflon tubes. The optimum sterilization condition of CT was fixed for 1.5 min at 2 L/min in overall quality aspects; also, 5~6 log cycle decrease of viable cell numbers of total bacteria and yeast was observed at this operating condition. Quality changes of UV-sterilized CT were examined by UV irradiation of CT followed by storing at $30^{\circ}C$ for 8 days. To evaluate quality changes of UV-sterilized CT, pH, amino nitrogen content, acidity, reducing sugar content and viable cell numbers of total bacteria and yeast were measured. The growth of yeast and bacteria was retarded, showing around $10^8\;CFU/mL$ even after 4 days and $10^8\;CFU/mL$ after 6 days, respectively. Also, UV sterilized CT showed no changes in pH, titratable acidity, and amino nitrogen content during storage except reducing sugar content. UV sterilization did not cause significant difference in L, a, and b values between CT and UV-sterilized CT over the storage period.

• Culinary science and hospitality research
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• v.21 no.1
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• pp.267-280
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• 2015

This study was carried out to evaluate the quality characteristics of Takju, Yakju, Spirit made by various cereal Nuruks which were made by Jokuk(whole wheat), Bunkuk(wheat flour), Maekkuk(whole barley). pH, Brix, cell number of yeast, alcohol content, flavors, organic acid, and sensory evaluation of brews were employed to analyze current study. Results showed that pH value of brews during fermentation decreased, while Brix value increased. In addition, alcohol contents increased up to 11 day's fermentation, but there were no significant differences among Jokuk, Bunkuk and Maekkuk(p<0.05). Cell numbers of yeast dramatically increased up to 5 day's fermentation, and then decreased. After 13 day's fermentation cell numbers of yeast were similar among Jokuk, Bunkuk and Maekkuk. In terms of analysis of flavor components, acetone and n-amyl alcohol were not detected in all brews, however fusel oil level was 494.65 mg/L in Maekkuk, and 525.4 mg/L in Bunkuk. Lactic acid showed the highest level in organic acid analysis. Furthermore, Jokuk and Maekkuk showed highest score in Takju, Maekkuk showed highest score in Yakju in sensory evaluation, although Jokuk, Bunkuk, and Maekkuk revealed similar score in spirit.

• The Plant Pathology Journal
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• v.31 no.2
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• pp.108-114
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• 2015

Curvularia lunata is an important maize foliar fungal pathogen that distributes widely in maize growing area in China, and several key pathogenic factors have been isolated. An yeast two-hybrid (Y2H) library is a very useful platform to further unravel novel pathogenic factors in C. lunata. To construct a high-quality full length-expression cDNA library from the C. lunata for application to pathogenesis-related protein-protein interaction screening, total RNA was extracted. The SMART (Switching Mechanism At 5' end of the RNA Transcript) technique was used for cDNA synthesis. Double-stranded cDNA was ligated into the pGADT7-Rec vector with Herring Testes Carrier DNA using homologous recombination method. The ligation mixture was transformed into competent yeast AH109 cells to construct the primary cDNA library. Eventually, a high qualitative library was successfully established according to an evaluation on quality. The transformation efficiency was about $6.39{\times}10^5$ transformants/$3{\mu}g$ pGADT7-Rec. The titer of the primary cDNA library was $2.5{\times}10^8cfu/mL$. The numbers for the cDNA library was $2.46{\times}10^5$. Randomly picked clones show that the recombination rate was 88.24%. Gel electrophoresis results indicated that the fragments ranged from 0.4 kb to 3.0 kb. Melanin synthesis protein Brn1 (1,3,8-hydroxynaphthalene reductase) was used as a "bait" to test the sufficiency of the Y2H library. As a result, a cDNA clone encoding VelB protein that was known to be involved in the regulation of diverse cellular processes, including control of secondary metabolism containing melanin and toxin production in many filamentous fungi was identified. Further study on the exact role of the VelB gene is underway.

• Mycobiology
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• v.49 no.5
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• pp.469-475
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• 2021

Three strains, YP416^T, YP421^T, and Y422, were isolated from soil samples in Pocheon City, Gyeonggi province, South Korea. The strains belong to two novel yeast species in the genus Mrakia. Molecular phylogenetic analysis showed that the strain YP416^T was closely related to Mrakia niccombsii. Still, it differed by 9 nucleotide substitutions with no gap (1.51%) in the D1/D2 domain of the LSU rRNA gene and 14 nucleotide substitutions with 7 gaps (2.36%) in the ITS region. The strain YP421^T differed from the type strain of the most closely related species, Mrakia aquatica, by 5 nucleotide substitutions with no gap (0.81%) in the D1/D2 domain of the LSU rRNA gene and 9 nucleotide substitutions with one gap (1.43%) in the ITS region. The names Mrakia terrae sp. nov. and Mrakia soli sp. nov. are proposed, with type strains YP416^T (KCTC 27886^T) and YP421^T (KCTC 27890^T), respectively. MycoBank numbers of the strains YP416^T and YP421^T are MB 836844 and MB 836847, respectively.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.2
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• pp.211-220
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• 2017

Objective: The aim of the present study was to investigate the effect of yeast with bacteriocin and Lactobacillus cultures (mixture of Lactobacillus agilis BCRC 10436 and Lactobacillus reuteri BCRC 17476) supplements, alone or in combination, on broiler chicken performance. Methods: A total of 300, 1-d-old healthy broiler chickens were randomly divided into five treatment groups: i) basal diet (control), ii) basal diet+0.25% yeast (Saccharomyces cerevisiae) (YC), iii) basal diet+0.25% yeast with bacteriocin (BA), iv) basal diet+Lactobacillus cultures (LAB), and v) basal diet +0.25% yeast with bacteriocin+Lactobacillus cultures (BA+LAB). Growth performance, cecal microbiota, cecal fermentation products, and blood biochemistry parameters were determined when chickens were 21 and 35 d old. Results: The supplementation of YC, BA, and BA+LAB resulted in a significantly better feed conversion rate (FCR) than that of the control group during 1 to 21 d (p<0.05). The LAB supplementation had a significant effect on the presence of Lactobacillus in the ceca at 35 d. None of the supplements had an effect on relative numbers of L. agilis and L. reuter at 21 d, but the BA supplementation resulted in the decrease of both Lactobacillus strains at 35 d. The BA+LAB supplementation resulted in higher short chain fatty acid (SCFA) in the ceca, but LAB supplementation significantly decreased the SCFA at 35 d (p<0.05). All treatments tended to decrease ammonia concentration in the ceca at 21 d, especially in the LAB treatment group. The BA supplementation alone decreased the triacylglycerol (TG) concentration significantly at 21 d (p<0.05), but the synergistic effect of BA and LAB supplementation was required to reduce the TG concentration at 35 d. The YC supplementation tended to increase the plasma cholesterol at 21 d and 35 d. However, the BA supplementation significantly decreased the cholesterol and low density lipoprotein cholesterol level at 35 d. In conclusion, the BA+LAB supplementation was beneficial to body weight gain and FCR of broiler chickens. Conclusion: The effect of BA and LAB supplementation may be a result of the growth of lactic acid bacteria enhancement and physiological characterization of bacteriocin, and it suggests that the BA and LAB supplementation level or Lactobacillus strain selection should be integrated in future supplementation designs.

• The Korean Journal of Food And Nutrition
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• v.12 no.3
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• pp.226-232
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• 1999

To evaluate the characteristics of modified nuruk made by inoculation and cultivation of Rhizopus jap-onicus T2, Aspergillus oryzae L2 and hansenula sp. BC26 three different Takju mashes were made with modified Nuruk commercial Nuruk and rice koji and the changes in microorganisms and major compon-ents of mashes were investigated uring brewing. The numbers of yeast kept higher in the mash of mod-ified Nuruk or rice koji. The numbers of lactic acid bacteria were high in mash of commercial Nuruk but those were not in mash of modified Nuruk or rice koji. all mashes showed stable pH in a day and the pH kept higher in mash of modified Nuruk than in that of commer-cial Nuruk or rice koji. Increase in the content of total acid was moderate in mash of modified Nuruk or rice koji but it was too much in that of commercial Nuruk. increase in the content of amino acid was much highr in mash of modified Nuruk or commercial Nuruk than in that of rice koji. Increase in the content of alcohol was more rapid in mash of modified nuruk or rice koji than in that of commercial Nur-uk. The content of reducing sugar kept highter in mash of commercial Nuruk or modified Nuruk than in that of rice koji. A small amount of modified Nuruk accomplished favorable fermentation showing nor-mal patterns in microbiological and physicochemical changes during brewing.

• Korean Journal of Food Science and Technology
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• v.43 no.1
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• pp.45-50
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• 2011

In this study, the influence of mixed starter compositions using Saccharomyces cerevisiae and three mixed probiotics, including Bifidobacterium longum, Enterococcus faecium, and Lactobacillus acidophilus on sourdough and bread preparation was examined. The following probiotic and yeast mixing ratios were used: Exp. 1, probiotics:yeast=2.0:0.1; Exp. 2, 1.5:0.1; Exp. 3, 1.0:0.1 (g/g). Starters for the sourdough preparation were incubated separately for 15 hr, combined, then further incubated for 10 hr. Exp 2 resulted in an increase in the numbers of probiotics and yeast in sourdough by 100 times but reduced pH. This is also reflected by the extent of the acidity increase in sourdough produced in Exp. 2. Among the three groups, bread volume and crumb elongation increased in Exp. 2, but crumb fineness and aroma compounds were not significantly different. In a sensory evaluation, flavor, taste, and overall acceptance for the sourdough produced in Exp. 2 improved markedly.

• Biotechnology and Bioprocess Engineering:BBE
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• v.5 no.6
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• pp.400-406
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• 2000

Since the 1950s, the numbers of species and chemicals produced have significantly increased. Despite the fact that industrial chemicals have given us numerous benefits, there is no doubt that they have damaged the environment. The chemicals being dispersed on the earth should be carefully controlled to prevent adverse effects. Bioassay is one of the methods to assess chemical safety. In bioassay systems, chemical safety is estimated by monitoring biological responses to environmental pollutants and newly synthesized chemicals. This report introduces multiple-point bioassay systems that are based on chemical sensitivities of microorganisms, responses of one kind of organism, and micro-array technology. Multiple-end-point bioassays enable the prediction of chemicals in the environment and the understanding of toxicities of newly synthesized chemicals.