• Title/Summary/Keyword: mixed culture.

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Preparation of Yogurt Added with Angelica keiskei Juice and Its Quality Characteristics

  • Chung, Hai-Jung
    • Preventive Nutrition and Food Science
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    • v.6 no.2
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    • pp.96-100
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    • 2001
  • Mixtures prepared from whole milk with added skin milk powder(2.5%, w/v) and Angelica keiskei juice (1.5%, w/v) were fermented with lactic acid bacteria (single and mixed culture of Lactobacillus bulgaricus and Strpetococcus thermophilus) for 24 hours. The fermented mixtures (curd yogurt) were evaluated for acid production (pH and titratable acidity), cell numbers, viscosity, sensory property and keeping quality. Results indicated that the addition of Angelica keiskei stimulated the acid production by lactic acid bacteria. The number of viable cells reached 4.5~7.3$\times$10$^{9}$ CFU/mL for Angelica keiskei-added yogurts, while 3.3~5.1$\times$10$^{9}$ CFU/mL for control yogurts. Viscosity of Angelica keiskei-added yogurts was higher (3,609~3,854 centipoises) than that of control yogurts(3,346~3,700 centipoises). Of the microorganism tested, mixed culture of Lactobacillus bulgaricus and Streptococcus thermophilus was most effective in acid production. The overall sensory score showed that Angelica keiskei yogurt fermented with Streptococcus thermophilus was evaluated as good as control yogurt. When yogurts were stored at 4$^{\circ}C$ for 12 days, pH, titratable acidity and viable cells of lactic acid bacteria were not significantly changed(p<0.05).

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Isolation and Cultivation Characteristics of Acetobacter xylinum KJ-1 Producing Bacterial Cellulose in Shaking Cultures

  • Son, Chang-Jin;Chung, Seon-Yong;Lee, Ji-Eun;Kim, Seong-Jun
    • Journal of Microbiology and Biotechnology
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    • v.12 no.5
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    • pp.722-728
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    • 2002
  • Eight strains producing bacterial cellulose (BC) were isolated from rotten fruits and traditionally fermented vinegars. One of the isolated strains from the rotten grape in Gwangju, Korea, maintained a relatively stable BC production in shaking cultures. This isolated strain proved to be Acetobacter xylinum, based on several biochemical and morphological tests. It was shown that the slant-baffled flask was more efficient than the conventional flask for the BC production in shaking cultures. To determine the most suitable carbon and nitrogen sources for the production of BC, various compounds were examined. Fructose was found to be the most effective carbon source with an optimal concentration of 2%. Mixed carbon source (glucose:fructose=1:3) was also better than glucose or fructose alone. Optimal nitrogen source, when basal medium was used, was 10% (v/v) com steep liquor (CSL). When com steep liquor was used with a mixed carbon source (glucose:fructose=1 :3),4% CSL exhibited the best BC production. Based on these results, a defined medium was developed for the BC production by Acetobacter xylinum KJ-1. When this medium was used under optimal culture conditions, the BC production was 7.2 g/1, which was approximately 3 times higher than that with the traditional HS medium.

Quantitative Analysis of Leuconostoc mesenteroides and Lactobacillus plantarum Populations by a Competitive Polymerase Chain Reaction

  • Koh, Young-Ho;Kim, Myoung-Dong;Han, Nam-Soo;Seo, Jin-Ho
    • Journal of Microbiology and Biotechnology
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    • v.12 no.5
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    • pp.801-806
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    • 2002
  • A multiplex competitive polymerase chain reaction (PCR) method was developed for the rapid identification and quantification of Leuconostoc mesnteroides and Lactobacillus plantarum populations which are the key microorganisms in kimchi fermentation. The strain-specific primers were designed to selectively amplify the target genes encoding 165 rRNA of L. plantarum and dextransucrase of L. mesenteroides. There was a linear relationship between the band intensity of PCR products and the number of colony forming units of each model organism. The PCR quantification method was compared with a traditional plate-counting method f3r the enumeration of the two lactic acid bacteria in a mixed suspension culture and also applied to a real food system, namely, watery kimchi. The population dynamics of the two model organisms in the mixed culture were reliably predictable by the competitive PCR analysis.

A STUDY ON THE CYTOTOXICITY OF THE ROOT CANAL SEALERS (근관충전용(根管充塡用) sealer의 세포독성(細胞毒性)에 관한 연구(硏究))

  • Lee, Seung-Jong;Kim, Yung-Hai
    • Restorative Dentistry and Endodontics
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    • v.16 no.1
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    • pp.25-40
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    • 1991
  • Four root canal sealers, Apatite Root Sealer I and II composed mainly of hydroxyapatite/tricalciumphosphate, Sealapex containing calcium hydroxide, and Roth Sealer composed of zinc oxide - eugenol were compared on the culture of L929 fibroblasts. MIT (Methyl Thiazole Tetrazolium Bromide) colorimetric technique was used to measure the mitochondrial dehydrogenase activity. Results were as follows: 1. Hydroxyapatite/tricalcium phosphate mixed sealers were significantly less toxic compared with calcium hydroxide and zinc oxide - eugenol type sealers. High pH of the calcium hydroxide sealer and release of eugenol component from the zinc oxide - eugenol type sealer were presumed to be the cause of the toxicity of these two sealers. In no cases, there were more cytoblastic effects in hydroxyapatite/tricalcium phosphate mixed sealers compared to the control groups. 2. In all experimental groups, toxicity was decreased as dilutions were increased. However in zinc oxide-eugenol type sealer the cell activity was weakened for all dilution groups. 3. Regarding the effect of setting time, Apatite I and Sealapex were less toxic as the setting progressed. Apatite II kept constant regardless of the different time ellapsed after setting but Roth sealer revealed significantly higher toxicity for all experimental groups. 4. Comparing two different culture periods of 24 hours and 72 hours, Apatite I showed higher cell activities in longer period(72 hours) while Apatite II did not. Sealapex and Roth sealer, however, showed significantly lower cell activities in longer period.

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A Yogurt Like Product Development from Rice by Lactic Acid Bacteria (쌀을 이용한 젖산 발효 음료 개발)

  • Shin, Dong-Hwa
    • Korean Journal of Food Science and Technology
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    • v.21 no.5
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    • pp.686-690
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    • 1989
  • Non sticky short grain rice was liquidized by ${\alpha}-amylase$ from Bacillus species after cooking 20min at $121^{\circ}C$ and a lactic acid bacteria fermentation proceeded. The product using mixed culture of S. thermophilus, L. bulgaricus and L. plantarum was superior than the one of any single or mixed culture. The most acceptable pH of it was 3.70. It is suggested that L. plantarum is more deeply related to the product quality. Skim milk promoted lactic acid fermentation but the quality of the final product was not acceptable in the result of sensory evaluation. The acceptable dilution rate of final product was 1:3 (rice: water) by weight.

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Factors Influencing Biohydrogenation and Conjugated Linoleic Acid Production by Mixed Rumen Fungi

  • Nam, In-Sik;Garnsworthy, Philip C.
    • Journal of Microbiology
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    • v.45 no.3
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    • pp.199-204
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    • 2007
  • The objective of this study was to evaluate the effect of soluble carbohydrates (glucose, cellobiose), pH (6.0, 6.5, 7.0), and rumen microbial growth factors (VFA, vitamins) on biohydrogenation of linoleic acid (LA) by mixed rumen fungi. Addition of glucose or cellobiose to culture media slowed the rate of biohydrogenation; only 35-40% of LA was converted to conjugated linoleic acid (CLA) or vaccenic acid (VA) within 24 h of incubation, whereas in the control treatment, 100% of LA was converted within 24 h. Addition of VFA or vitamins did not affect biohydrogenation activity or CLA production. Culturing rumen fungi at pH 6.0 slowed biohydrogenation compared with pH 6.5 or 7.0. CLA production was reduced by pH 6.0 compared with control (pH 6.5), but was higher with pH 7.0. Biohydrogenation of LA to VA was complete within 72 h at pH 6.0, 24 h at pH 6.5, and 48 h at pH 7.0. It is concluded that optimum conditions for biohydrogenation of LA and for CLA production by rumen fungi were provided without addition of soluble carbohydrates, VFA or vitamins to the culture medium; optimum pH was 6.5 for biohydrogenation and 7.0 for CLA production.

Current Status of EM (Effective Microorganisms) Utilization (유용미생물 (EM, Effective Microorganisms)의 활용 현황)

  • Moon, Yun-Hee;Lee, Kwang-Bae;Kim, Young-Jun;Koo, Yoon-Mo
    • KSBB Journal
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    • v.26 no.5
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    • pp.365-373
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    • 2011
  • Effective Microorganisms (EM), a fermented medium developed by Professor Higa at the University of the Ryukyus, is a mixed culture containing dozens of microorganisms which are beneficial to nature including people, animals, plants and many microbial species in environment. EM is known to contain more than 80 kinds of anaerobic or aerobic microbes including photosynthetic bacteria, lactic acid bacteria, yeast, actinomycetes, fungi and so on, with yeast, lactic acid bacteria and photosynthetic bacteria as the main species of EM. Antioxidant effect generated by the concert of complex coexistence and coprosperity among these microbes is considered to be the main source of EM benefits. Currently, EM is earning an increasing attention with applications in agriculture, forestry, animal husbandry, fisheries, environment and medicine among others. At the same time, however, a quantitative interpretation of EM system based on a mixed culture model needs efforts from biochemical engineers for efficient production and further promotion of EM. In this paper, we describe the functions of major microbes in EM and current researches and applications of EM in agriculture, forestry, animal husbandry, fisheries, environment and medicine.

Fermentation Characteristics of Koji inoculated with Cordyceps sp. (동충하초를 이용한 코오지의 발효특성)

  • 권동진
    • Microbiology and Biotechnology Letters
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    • v.30 no.1
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    • pp.46-50
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    • 2002
  • To investigate the quality of Koji produced by Cordyceps sp., a mixed culture of Aspergillus oryzae and the Cordyceps sp. were inoculated in Koji making. Viable cell counts and counts of fungi spore during Koji making for 120 hours were increased rapidly within 24-48 hours, after then their changes were not shown significantly during Koji making. The activities of amylase and protease in Koji inoculated with the mixed culture of A. oryzae and Cordyceps sp. were superior to one with A. oryzae only. The sensory evaluation on the Koji with 0.5% (w/w) A. oryzae and 0.5% (w/w) Cordyceps sp. were evaluated to be superior to ones. The best quality of Koji is prepared from the mixture of Cordyceps sp. and A. oryzae with the ratio of 0.5% and 0.5% (w/w).

Rapid Preparation of Dongchimi-Juice for Naengmyon by Lactic Acid Bacteria Having High Antibacterial Activity (항균활성이 높은 젖산균에 의한 냉면용 동치미액의 속성제조)

  • 박상희
    • The Korean Journal of Food And Nutrition
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    • v.12 no.1
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    • pp.77-84
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    • 1999
  • The purpose of this study is to establish a rapid preparation method of Dongchimi-juice having favor-able flavor and high antibacterial activity against undesirable bacteria in Naengmyon-broth by using high antibacterial strains of lactic acid bacteria Lactobacillus homohiochii B21 and leuconostoc mesenteroid-es subsp. mesenteroides C16 as Dongchimi starter. When the two strains of lactic acid bacteria were used as starter mixed culture was better than single culture in acid production and antibacterial activity. When starter was not inoculated in Dongchimi fermentation the numbers of Gram negatives and colifor-ms were remarkably increased in early phase and antibacterial activity could scarcely be detected. But when starter was inoculated the numbers of Gram negatives and coliforms were sharply decreased from early phase and antibacterial ctivity was high. When Dongchimi was made with heat sterilized mat-erials and starter there were no Gram negatives and coliforms and antibacterial activity was high. The antibacterial activity of starter inoculated Dongchimi was maximum in 2 days of fermentation at 2$0^{\circ}C$ and was scarcely detected in six days. In consideration of coliform counts antibacterial activity and the flavor of Dongchimi the preparation method in which all materials were heat treated at 8$0^{\circ}C$ for 15 min-utes and inoculated with mixed starter of the two strains and fermented for 2 days at 2$0^{\circ}C$ was thoug-ht to be good.

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Design and Implementation of Fire Detection System Using New Model Mixing

  • Gao, Gao;Lee, SangHyun
    • International Journal of Advanced Culture Technology
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    • v.9 no.4
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    • pp.260-267
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    • 2021
  • In this paper, we intend to use a new mixed model of YoloV5 and DeepSort. For fire detection, we want to increase the accuracy by automatically extracting the characteristics of the flame in the image from the training data and using it. In addition, the high false alarm rate, which is a problem of fire detection, is to be solved by using this new mixed model. To confirm the results of this paper, we tested indoors and outdoors, respectively. Looking at the indoor test results, the accuracy of YoloV5 was 75% at 253Frame and 77% at 527Frame, and the YoloV5+DeepSort model showed the same accuracy at 75% at 253 frames and 77% at 527 frames. However, it was confirmed that the smoke and fire detection errors that appeared in YoloV5 disappeared. In addition, as a result of outdoor testing, the YoloV5 model had an accuracy of 75% in detecting fire, but an error in detecting a human face as smoke appeared. However, as a result of applying the YoloV5+DeepSort model, it appeared the same as YoloV5 with an accuracy of 75%, but it was confirmed that the false positive phenomenon disappeared.