• Food Science and Biotechnology
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• v.15 no.3
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• pp.469-473
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• 2006

Film-forming yeasts generate an undesirable yeasty flavor in fermented vegetables such as kimchi in the presence of oxygen. Antimicrobial materials including garlic oil (GO), heated garlic (HG), and allyl alcohol (AA) were investigated for use as alternative natural food preservatives to inhibit the growth of film-forming yeasts in fermented vegetables. Using the fermentation of cucumber pickles as a model system, GO, HG, and AA were effective in preventing film formation at concentrations of 0.006, 3.0, and 0.02%, respectively. The effectiveness of HG in preventing the growth of a film yeast, Hansenula anomala, was not influenced by pH, while that of potassium sorbate, a typical anti-yeast food preservative, was highly dependent on pH. All tested materials were effective when added at the beginning of fermentation due to their negligible inhibitory activity toward lactic acid bacteria.

• Journal of the East Asian Society of Dietary Life
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• v.10 no.4
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• pp.288-297
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• 2000

To understand the effect of radish on growth of food born microorganisms, mashedflesh radishes were extracted by using acetone and distilled water. Their effect was assayed by measuring the optical density of cultural broth of food born microorganisms. In the experiment, seven strains of yeast were used as the test organism. Acetone extract inhibited growth of the cells of L. plantarum, L. sake and Danmuji film yeast. Growth of the film yeast was drastically inhibited in the concomitant presence of 0.03% extract, while other microbes such as L. faecalis, P. pentosaceus, B/ subtilis and E. coli grew by succeeding cultivation for 4 to 8 hour after addition of the extract. Water extract, on contrast to acetone extract, at he concentrations of 0.1∼1.5% stimulated the growth of lactic acid bacteria. Culture of L. faecalis and L. sake showed an optical density higher than that of control by 40∼50 times. The effect was not so apparent against E. coli, S. aureus and Danmuji film yeast.

• Current Research on Agriculture and Life Sciences
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• v.1
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• pp.159-163
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• 1983

Film-formation, which often occurs during storage of apple wine, owing to contamination by film-forming yeasts, results in inferior products. Therefore, for the purpose of preventing this occurrence, we isolated and identified yeast strain. Among the total number of 45 yeast strains which were isolated from contaminated apple wine in winery, the strains FY-4 and FY-5 were found to be useful. The strain FY-5, which greatly formed film on apple wine, was identified as Hansenula beijerinckii or similar strain according to taxonomic characteristics.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.3
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• pp.327-334
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• 2017

Water and 75% ethanol extracts were prepared from defatted green tea seeds and evaluated for their anti-yeast activities. The antimicrobial activities of defatted green tea seed extracts (DGTSEs) were tested against food-spoilage bacteria, yeasts, and molds. DGTSEs exhibited antimicrobial activities with minimum inhibitory concentrations of $39{\sim}1,250{\mu}g/mL$ against three bacteria, two molds, and all tested yeast strains. Ethanol extract showed higher antimicrobial activity than water extract. The stability of anti-yeast activities of DGTSEs was examined under different conditions of temperature, pH, and NaCl concentrations. The anti-yeast activities of DGTSEs were stable at pH 3~9, 0~20% NaCl, and $100^{\circ}C$ for 30 min. However, anti-yeast activities of DGTSEs decreased upon heating at $70^{\circ}C$ for 24 h or $121^{\circ}C$ for 15 min. DGTSEs were applied to food models to determine their inhibitory effects on yeast film formation. Water and 75% ethanol extracts were effective in preventing yeast film formation at concentrations more than 156 and $39{\mu}g/mL$ in soy sauce, 156 and $78{\mu}g/mL$ in pickle sauce, and 78 and $39{\mu}g/mL$ in kimchi, respectively.

• Journal of the Korean Society of Food Culture
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• v.34 no.2
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• pp.201-207
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• 2019

This review summarizes the studies on a wide variety of yeast found in kimchi and the effects of yeast on kimchi fermentation, and discusses the direction for further research. Yeast belongs to the genera Trichosporon, Saccharomyces, Sporisorium, Pichia, Lodderomyces, Kluyveromyces, Candida, Debaryomyces, Geotrichum, Kazachstania, Brassica, Yarrowia, Hanseniaspora, Brettanomyces, Citeromyces, Rhodotorula, and Torulopsis have been identified using culture-dependent methods and metagenomics analysis. The application of yeast as a starter into kimchi has resulted in an extension of shelf life and improvement of sensory characteristics due to a decrease in the amount of lactic acid. On the other hand, some yeast cause kimchi spoilage, which typically appears as an off-odor, texture-softening, and white-colony or white-film formation on the surface of kimchi. In contrast to lactic acid bacteria, there are limited reports on yeast isolated from kimchi. In addition, it is unclear how yeast affects the fermentation of kimchi and the mechanism by which white colony forming yeast predominate in the later stage of kimchi fermentation. Therefore, more research will be needed to solve these issues.

• Korean Journal of Food Science and Technology
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• v.7 no.2
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• pp.61-68
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• 1975

This study was conducted (1) to isolate the film-forming yeast from the commercially available soy sauce, (2) to identify the state of soy sauce fermentation by the use of yeasts, (3) to confirm characteristics of yeasts. The result were as follows. 1. These yeast strains in the soy sauce fermentation test showed full fermentation of whole sugar content, reduction of the pure extract and relative reduction in total nitrogen. Soy sauce color was somehow faded to lower the stability of soy sauce. 2. In anti-fungal activity test butylparaben at a higher level 60 ppm., sodium propionate 2,400 ppm, sodium benzoate 800 ppm., menadion 165 ppm, showed their anti-fungal effect, while alcohol did not show the effect in the 3% additive group. 3. The optimum sodium chloride concentration for these strains in the 2% G.Y.P. medium was 5% and optimum temperature was $30^{\circ}C$. The extinction temperature was $62^{\circ}C$ for strain No-1 and No-3, and was $65^{\circ}C$ for No-2 and No-4. 4. The film-forming soy sauce turned out in the gas chromatogram to possess much flavor of low boiling point as compared with the standard. These flavors were considered due to flavor spoilage of the soy sauce. 5. These isolated yeasts were identified Saccharomyces rouxii (film-forming yeast) in the Lodder's taxanomic study.

• Journal of the Korean Society of Food Culture
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• v.8 no.3
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• pp.249-255
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• 1993

To minimize the waste amount of surface layer kochujang during aging, the effects of the three finishing methods(nothing, salt scatering and Polyethylene film on the kochujang surface) and sunning(conventional aging method) or nonsunning aging(cap covering) on water content, redness and spreadability, film forming yeast occurance and salinity of surface layer kochujang during 120 days aging were investigated. In the case of sunning aging, film forming yeast was not visually found on the surface. The surface layer kochujang was so low spreadability(zero) and very high salinity(18-30%) that could not eat. However, the aging method after PE-film covering on the kochujang surface, and then cap covering(nonsunning) was very effective in keeping of soundness of surface layer kochujang without film forming yeast growth on the surface kochujang, especially was greatly effective in keeping of redness, moderate moisture content and spreadability. The PE-film and cap covering aging were effective in prevention of water evaporation and $CO_2$ release, and in accumulation of ethanol and organic acids between the PE-film and surface layer of kochujang.

• Korean Journal of Microbiology
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• v.36 no.4
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• pp.299-305
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• 2000

Degradation behavior of the three commercial biodegradable polymers, namely poly(3-hydroxybutyrate) (PHB) Sky-Green/sup R/ (SG) and Mater-Bi/sup R/ (MB) was investigated using bacteria isolated from activated sludge and farm soil. Three PHB degrading bacteria, three SG degrading bacteria and one MB degrading bacteria were isolated. The PHB degrading bacteria were identified to be Flavimonas oryzihabitans, Corynebacterium pseudodiphtheriticum and Micrococcus diversus, while Pseudomonas vesicuraris, Pasteurlla multocida and Flavobacterium odoratum were identified as SG degrading bacteria. As for MB, Pseudomonas vesicuraris was isolated. The shake flask test for 28 days indicated that the rate of biodegradation of PHB, SG and MB in terms of weight loss were about 44∼69% 25∼32% and 29% respectively. The surface morphology of PHB, SG andMB films before and after degradation by microorganisms in an activated sludge soil was observed under SEM, demonstrating that the film surface had a very porous structure, and that microorganisms colonized heavily on the film surface. TOC and pH variation as a result of abiotic hydrolysis, or microbial growth in the absence of the polymers were compared to those due to degradation by F. oryzihabitans. Abiotic hydrolysis of PHB was three times as fast as that of SG and MB. Addition of yeast extract to the basal liquid medium accelerated the biodegradation of the polymers. Biodegradation of PHB was always faster than that of SG and MB irrespectively of the presence of yeast extract in the basal liquid medium.

• Korean Journal of Food Science and Technology
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• v.17 no.3
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• pp.203-207
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• 1985

Relationship between cell surface hydrophobicity and pellicle formation was studied in a film strain isolated from stored apple wine and identified as Hansenula beijerinckii FY-5. In the media containing non-ionic surface-active agents the pellicle formation of strain FY-5 was efficiently repressed, whereas growth of the yeast was possible, and also cell surface hydrophobicity was greatly decreased by the addition of these agents. These results indicate that a pellicle formation factor, which keeps yeast cells floating on the medium surface, is necessary for the pellicle formation, and surely this factor is the hydrophobicity of the cell surface. The pellicle formation in the film strains was abundant with the increase of the cell surface hydrophobicity, whereas the non-film strains had less hydrophobicity as compared with the film strains. Ethanol, as a sole carbon source, efficiently increased hydrophobicity more than glucose, and the hydrophobicity was lowered with the rise of pH. In the experiments of time course, the hydrophobicity was increased in proportion to cell growth, and was maximum during the stationary phase.

• Journal of the Korean Society of Food Culture
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• v.7 no.4
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• pp.297-301
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• 1992

To investigate effects of the surface finishing methods (A : conventional press stone, B : enclosing in polyethylene (PE) bag, C : press-tone wrapped with PE film and D : covered with Chinese cabbage leaves 4cm in thickness on Kimchi) on Kimchi quality, pH-values, redness, film forming yeast growth, hardness and sensory quality of Kimchi during storage (for 60 days, at $10{\pm}5^{\circ}C$) in glass vessel $(11{\times}30cm)$ were investigated. pH of the top layer of A, C and D sample were higher than the optimum pH (4.2) of Kimchi, film forming yeast occurred on the surface of Kimchi, color of top layer Kimchi juice was darkened, and panel score of freshness and firmness was significantly worse (p<0.01) than that of sample B. However, in the case of Kimchi stored in PE bag (B), film forming yeast were can't detected visually in the surface of Kimchi, pH values were low as good quality Kimchi, freshness and firmness panel scores and hardness were significantly better (p<0.01) than A, C and D, and redness of juice of top layer of B was also preserved clearly for 60 days. Accordingly among the four surface finishing methods, the B-method was most effective in preserving of y of Kimchi.