• Korean Journal of Food Science and Technology
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• v.28 no.2
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• pp.253-259
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• 1996

To investigate the yeast florae in the traditional and commercial Kochujang, computer identification systems, Vitek, API kit and conventional identification methods were used. Yeast florae of each process were compared and their typical physiological characteristics were also tested. Various process intervals yielded 330 colonies, which resulted in 11 species 184 strains classified. They were identified into Candida glabrata C. guilliermondii. C. humicola. C. rugosa, C. zeylanoides, Cryptococcus uniguttulatus, Pichia farinosa, Rhodotorula glutinis, Saccharomyces cerevisiae and Zygosaccharomyces rouxii. The strains of Candida, Pichia, Saccharomyces and Zygosaccharomyces were existing in both processes. In case of commercial process, the maximum distribution of Z. rouxii and S. cerevisiae were 33% at 15 day fermentation and 13% at 21 day, respectively. The distribution of Candida spp. was gradually decreased throughtout the fermentation period from 40% to 10%. In the traditional process, the maximum distribution of Z. rouxii and S. cerevisiae were 53% after 3 months and 26% after 7 months, respectively, S. cerevisiae and Z. rouxii showed distintive growth pattern at the high concentration of glucose and sodium chloride and played important roles in both processes of fermentation. Physiological tests revealed that only two major yeasts. S. cerevisiae and Z. rouxii, showed vigorous carbon dioxide formation under the tested conditions.

• Preventive Nutrition and Food Science
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• v.21 no.3
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• pp.221-226
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• 2016

A new type of doenjang was manufactured by mixing soaked soybean, koji (Rhizopus oryzae), cheonggukjang (Bacillus amyloliquefaciens MJ1-4 and B. amyloliquefaciens EMD17), and Pichia farinosa SY80 as a yeast, salt, and water, followed by fermentation with koji that was made by fermenting whole wheat with R. oryzae. The mixed culture doenjang was designed to have a more palatable flavor and stronger biological activities than the conventional product. The extract of mixed culture doenjang showed higher antioxidant activity than the commercial doenjang as evaluated by the ferric reducing antioxidant power assay although it was not significantly different from the commercial product in 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) radical scavenging activities. Further, the mixed culture doenjang reduced intracellular reactive oxygen species levels and protected cells from glutamate-induced cytotoxicity more efficiently in human hippocampal HT22 neuroblastoma cells than the commercial doenjang. In conclusion, a newly-developed mixed culture doenjang had a strong antioxidant activity in vitro and cultured cell model systems, exhibited a potential to prevent oxidative stress-associated disorders although animal and clinical studies are needed to confirm its in vivo efficacy.

• Korean Journal of Microbiology
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• v.50 no.4
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• pp.351-359
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• 2014

A beverage was produced by the fermentation of mixed extracts from the various fruits, vegetables, algae, and medical herbs. The physicochemical properties of the fermented beverage of plant extracts (FBPE) and microbial diversity were analyzed in cultures enriched from FBPE using 16S and 26S rRNA gene sequence analyses. The pH, acidity, $^{\circ}brix$, reducing sugar, and alcohol contents of the FBPE were determined to be the 3.48, 1.68%, 70.0, 1,026 g/L, and 3.5%, respectively. The most abundant free sugar and organic acid in the FBPE were glucose (567.83 g/L) and tartaric acid (93.68 mg/L), respectively. Lactobacillus homohiochii was the predominant species in all enriched culture samples: 100% of the species in 0B (0% sugar) and 40B (40% sugar) libraries and 95.6% of 20B library (20% sugar). Lactobacillus fructivorans was detected in the 20B library. The predominant species in the samples of enrichment cultures collected from FBPE with three different sugar concentrations were: Candida zeylanoides (45.2%) in the 0Y library (0% sugar), Candida lactis-condensi (35.7%) and C. zeylanoides (35.7%) in the 20Y library (20% sugar), and C. lactis-condensi (38.1%) in the 40Y library (40% sugar). This result may provide a useful frame of reference for further analyses of microbial population dynamics in FBPE.

• Korean Journal of Poultry Science
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• v.29 no.3
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• pp.225-231
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• 2002

Total 240 of ISA Brown layers were employed in this experiment to study the effects of single or mixed feeding of Lactobacillus and yeast on the performance and intestinal microflora of laying hens. They were randomly allocated to six dietary treatments; None(Control), Pichia farinosa(PF), Lactobacillus crispatus avihen1 (LCH), Lactobacillus vaginalis avihen1(LVH), LCH＋PF, and LVH＋PF. Viable microflora were added to meet 3${\times}$10$\^$6/ cfu PF and 10$\^$7/ cfu Lacrobacillus per g of feed. There were four replicates per treatment, and 10 birds per replicates. Laying performance was recorded for 10 weeks, followed by a metabolism trial during which nutrient utilization, pattern of intestinal microflora and fecal NH$\sub$3/ emission were examined. Egg production and daily egg mass of birds fed either single or mixed microorganisms were significantly higher than those of the control(P<0.05). Egg weight and feed intake were not statistically different among all treatments. However, feed conversion ratio tended to improve by the supplementation of microbes. Digestibility of crude protein, ether extract and crude ash tended to improve in Lactobacillus treatments, however, there were not statistically different. With regards to the number of intestinal microbes, number of anaerobes were increased in microbes feeding group. Eggshell quality of PF layers was significantly poorer than those of the other treatments. No consistent trend was found in Haugh Unit among all treatments. Fecal NH$\sub$3/ gas emission was significantly lower in LVH, LVH＋PF and LCH＋PF than the other treatments(P<0.05). From the result of this experiment, it could be concluded that single or mixed feeding of Lactobacillus and yeast improves the laying performance and decreases the fecal ammonia gas emission. No synergic effect was found when both microbes were mixed and fed to the layers.

• Microbiology and Biotechnology Letters
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• v.44 no.3
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• pp.254-260
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• 2016

Doenjang samples were prepared by inoculation of multiple starters consisting of two Bacillus spp., one yeast, and one fungus. Doenjang A was fermented with Bacillus amyloliquefaciens EMD17, B. amyloliquefaciens MJ1-4, Pichia farinosa SY80, and Rhizopus oryzae. Doenjang B and C were fermented with the same yeast and fungus but different Bacillus strains; namely, B. amyloliquefaciens EMD17 and B. subtilis CH3-5 for doenjang B, and B. amyloliquefaciens MJ1-4 and B. subtilis CH3-5 for doenjang C. Doenjang D was fermented with microorganisms present in rice straw (control). The doenjang samples were spiked with B. cereus ATCC14579 at two different levels, 10⁴ CFU/g doenjang (I) and 10⁷ CFU/g doenjang (II). All eight doenjang samples were fermented for 70 days at 25℃. Growth of B. cereus was inhibited in doenjang A, B, and C, with the bacterial cell count after 70 days being less than the initial 10⁴ CFU/g added, whereas B. cereus was not inhibited in doenjang D. Doenjang B showed the strongest inhibitory activity against B. cereus, with a cell count of less than 10³ CFU/g after 42 days, even when B. cereus was initially added at 10⁷ CFU/g. Some properties of the doenjang samples, such as pH, TA, and amino-type nitrogen content, were similar to those of doenjang fermented with starters only. The results indicate that carefully selected starters can effectively prevent the growth of B. cereus during doenjang fermentation.