• Microbiology and Biotechnology Letters
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• v.8 no.2
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• pp.87-92
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• 1980

These experiments were conducted to manage more safe the selected strains and improve their characteristics. The results obtained were as follows: Preservation on soil at the range of 0 to 5 C was suitable and there were no remarkable changes on their abilities to produce citric acid until 10 months preservation. The successive transfer of spore slightly stimulated the selected strain, M-315 to produce citric acid and the spore precultured on sporulation medium for 7-10 days was desirable as inoculum. Under UV-irradiation from the selected strains, 109 mutants whose morphological characteristics were changed were isolated. Among them, the mutant M-80-12 was shown 3.2％ increase on acid producing ability than that of its parent.

• Microbiology and Biotechnology Letters
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• v.16 no.2
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• pp.111-118
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• 1988

The growth inhibition of enteropathogenic Escheriohia coli $A_2$and Escherichia coli G$_7$, causing the diarrhea in piglets, by the organic acid producing bacteria was studied in vitro. The metabolites of the organic acid bacteria, such as lactic acid, acetic acid inhibited the growth of E. coli $A_2$and E. coli G$_7$ in BL medium. The more the organic acid producing bacteria have ability to produce the organic acids, the higher these bacteria excelled the inhibitory efficacy against enteropathogenic E. coli. Among the strains examined, Lactobacillus casei Y and Streptococcus faecium C showed relatively strong growth inhibition against enteropathogenic E. coli.. When the organic acid producing bacteria and the enteropathogenic E. coli were incubated simultaneously in BL medium, bacteriostasis of E. coli was observed when the pH of BL culture was lowered to 5.0, and bacteriocidal effect was observed when the pH became Bess than 4.5, E. coli. $A_2$was more resistant to the organic acid bacteria than E. coli G$_7$.

• Microbiology and Biotechnology Letters
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• v.7 no.4
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• pp.217-223
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• 1979

Six strains of mold which had high saccharifying and acid-productive ability were isolated from wild sources. The strain M-80 among them and Aspergillus kawachii, which was generally used as rice makkulli koji were used for this studies. The results obtained were summarized as follows. 1) $\alpha$-amylase activities of the strain M-80 and Asp, kawachii showed similarly as about 140W. V., while $\beta$-amylase activity of M-80 was 54 A. U. and Asp. kawachii was 40 A. U. 2) Acid protease activity of M-80 was higher then Asp. kawachii but alkaline protease activity was lower Asp. kawachii respectively. 3) The contents of total acid, ethanol and fusel oil in makkulli brewing with M-80 were higher those of Asp. kawachii and methanol contents of the tested two strains were about 33mg/％. 4) Fifteen kinds of free amino acid were detected from makkulli brewing of two strains, and free amino acid contents of M-80 were 10％ higher than those of Asp. kawachii.

• Journal of Food Hygiene and Safety
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• v.16 no.3
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• pp.206-211
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• 2001

This experiment was conducted to investigate the effects of mixed culture with mycotoxigenic and non-mycotoxigenic fungi on mycotoxin production. For this work, Aspegillus flavus (aflatoxin producing strain), Aspegillus niger (non-mycotoxigenic strain) and Penicillium griseofulvum (patulin producing strain)were cultured in 5 ml SLS medium for 15 days under single or mixed culture. Aflatoxin was determined by direct competitive ELISA, whereas, patulin was measured by HPLC. The mycelial growth, pH and total acidity were also observed by general methods. The mycelial growth was slightly decreased in the mixed culture, meanwhile total acidity was increased and pH was shown lower than that in single culture. Aspergillus flavus produced 145 $\mu\textrm{g}$/ml of aflatoxin for 12 days single culture, but in mixed culture, aflatoxin was decreased to 93%, and was shown as 10.16$\mu\textrm{g}$/ml level. Patulin production in mixed culture was also decreased to 69.3% and was shown only 23.72$\mu\textrm{g}$/ml level as compared with in single culture.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2005.10a
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• pp.276-279
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• 2005

본 연구는 가루녹차를 첨가한 기능성 요구르트를 개발하기 위한 기초 연구로 가루녹차의 농도별 첨가가 요구르트 균주의 증식 및 산 생성에 미치는 영향을 조사하였다. 단독균주의 경우 가루녹차의 첨가 농도를 달리하였을 때 Streptococcus thermophilus와 Lactobacillus casei는 가루녹차 첨가에 의해 증식 효과는 아주 미비하였으나 억제 효과가 나타나지 않았으며, Lactobacillus acidophilus는 배양 9시간부터 가루녹차 첨가구에서 대조구에 비해 높은 균수를 보이며 약간의 생육 촉진 효과를 보였고, 배양 12시간부터 pH가 하락하였으며 적정산도는 상승하였다. 그러나 가루녹차의 첨가량에 따른 생육과 산 생성 정도에 미치는 영향의 차이는 뚜렷하지 않았다. 혼합균주의 경우 단독균주로 배양하였을 때보다 가루녹차에 의한 유산균의 증식이 촉진되며, pH 저하와 적정산도 상승이 뚜렷하였다. 따라서 가루녹차 첨가 기능성 요구르트 제조 시 가루녹차를 0.5%${\sim}$l.0% 첨가하여 유산균을 혼합균주로 사용하는 것이 이들 유산균의 증식에 가장 적합한 것으로 나타났다.

• Korean Journal of Food Science and Technology
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• v.16 no.3
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• pp.285-290
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• 1984

Growth characteristics of six lactic acid bacteria in whey-soy milk mixtures were investigated to obtain basic informations for processing cheese-like product by coprecipitation of whey and soy proteins. Streptococcus cremoris and Lactobacillus acidophilus produced more aicd than other lactic acid bacteria both in whey-soy milk mixture and in soy milk. Lactic acid fermentation was accelerated in whey-soy milk mixture than in soy milk with all the lactic aicd bacteria, and specially with S. lactis and S. cremoris in great extent. The number of viable cell of 1:1 mixed culture of S. lactis and S. cremoris in whey soy milk mixture was about 10 times than in soymilk. It was mainly the effect of lactose in the whey that increased the acid production by lactic aicd bacteria in whey-soy milk mixture although the degree of acceleration depended on the ability of microorganism to use carbohydrates. The optimum amount of lactose added to soy milk to accelerate the acid production was 0.8g/100ml soy milk.

• Korean Journal of Food Science and Technology
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• v.25 no.6
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• pp.747-752
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• 1993

A curd yogurt was prepared from milk added with skim milk powder or four kinds of starch such as rice starch, wheat starch, corn starch and potato starch. The effects of starch addition at 2%(w/v) level on acid production by lactic acid bacteria in milk was investigated. The effects of starch addition on quality of curd yogurt in terms of apparent viscosity, sensory property and volatile aroma compounds were also examined. Addition of starch markedly stimulated the acid production by lactic acid bacteria. Among four organisms tested, Lactobacillus jugurti produced the highest amount of acid. Apparent viscosity of curd yogurt added with starch was significantly higher than that of control. Curd yogurt fermented with L. jugurti showed pseudoplastic and thixotropic characteristics. Sensory property of curd yogurt added with corn starch or rice starch was evaluated as slightly better than reference sample, but that with potato starch was evaluated as the worst among all samples. Acetaldehyde, acetone, ethanol and butanol were detected by gas chromatographic analysis.

• Korean Journal of Food Science and Technology
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• v.29 no.3
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• pp.533-538
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• 1997

Lactobacillus bulgaricus and Kluyveromyces lactic were inoculated to Jangyeob and Jinpum soymilks single or together after the addition of different amounts of lactose to increase the formation of lactic acid and sensory evaluation. The decrease of pH and the increase of acid production during the fermentation of soy yogurts were more effective when lactose was added. And the single culture method was more effective in decreasing pH and in increasing acid production than the mixed culture method. Without lactose, the growth of lactic acid bacteria in samples increased by mixed culture method than by single culture method. However, the growth of lactic acid bacteria increased more in the by single cultured samples than in the mixed cultured samples by the addition of lactose. Beany flavor decreased more in soy yogurts compared with Jangyeob and Jinpum soy milks, and Jinpum soy yogurts had less beany flavor than Jangyeob soy yogurts. In sour taste, Jangyeob soy yogurt prepared by mixed culture for 36 hr incubation with 4% lactose showed the poorest score, while soy yogurts containing 2% lactose showed significantly better scores and no significant difference compared with milk yogurt. Soy yogurts containing 2% lactose showed no significant difference in overall acceptability compared with milk yogurt.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1978.04a
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• pp.97.4-97
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• 1978

이미 발표한 바와 같이 사과산을 강력히 분해하는 Schizosacharomyces japonicus var. japonicus를 과실주에 직접 적용하기 위한 기초적 자료를 얻고자 하여 양조학적 성질을 검토한 바를 보고하고자 한다. 사과산의 정량은 paper chromatograohy에 의하여 발색시킨 사과산의 spot를 Goodban의 방법에 의하여 비색 정량하였다. 본 공시균은 pH 4.2~4.8, 알코올 12% 이하, $SO_2는$ 150ppm 이하, $Mn^{2+}$ 은 $MnSO_4$ 로서 0.01% 이하의 농도에서 양호한 Maloalcohol 발효를 유도하였다. 더욱 공시균은 7.5%의 알코올을 생성시켰다. 당류의 첨가는 Maloalcohol 발효를 저해하였으며 정치 배양과 진탕 배양과의 차이점은 거의 인정할 수 없으나 공시균의 생육은 진탕 배양하므로 촉진되었다. 0.3%의 사과산을 $30^{\circ}C에서$ 정치 배양하므로 배양 6일로서 완전히 분해하였다.

• Korean Journal of Food Science and Technology
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• v.23 no.5
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• pp.587-592
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• 1991

The curd yogurt was prepared from milk or milk added with skim milk powder or four types of rice powder. Acid production by lactic acid bacteria in milk containing additive of 2% (w/v) was investigated and quality of curd yogurt (sensory property and keeping quality) was examined. Some organic acids in curd yogurt were analyzed by HPLC. Four types of rice powder, particularly brown rice, stimulated acid production by lactic acid bacteria more than control (milk yogurt). Among four organisms tested, Leuconostoc mesenteroides and Lactobacillus bulgaricus produced more acid than L. casei and L. delbrueckii. HPLC analysis of organic acids in curd yogurt showed that the amount of lactic acid markedly increased during the fermentation by L. bulgaricus for 24 hours while the amount of citric acid markedly decreased. Addition of rice powders to milk slightly reduced sensory property of curd yogurt. Among four types of rice powder tested, tongil rice added sample showed better sensory acceptability than other samples. When curd yogurt was kept at $5^{\circ}C$ for two weeks, acidity and number of viable cells of curd yogurt were not changed.