• Applied Biological Chemistry
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• v.36 no.5
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• pp.352-357
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• 1993

The effects of culture broth filtrates, sugar changes and utilizationon the growth and acid production of P. freudenreichii KFCC 31227and L. acidophilus KFCC 32825 were investigated in S.G.Y.(Skim milk, glucose, yeast extract) and SMW (skin milk whey)medium by the single and mixed cultures. The growth and acid production by mixed culture and in cultured broth filtrate of the other party were more affected than those of single culture and self-cultured broth filtrate. When the two strains were cultured, P. freudenreichii KFCC 31227 utilized with lactose more than glucose and L. acidophilus KFCC 32825 was glucose more than lactose in the growth and acid production. The mixed culture of two strains was more affected to sugar utilization than single culture. This result was considered due to the synergistic effect by interaction of these two strains in mixed culture.

• Korean Journal of Food Science and Technology
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• v.25 no.2
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• pp.130-135
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• 1993

A curd yogurt was prepared from milk added with skim milk powder of four kinds of cereal. The effect of cereals at 2%(w/v) level on acid production by lactic acid bacteria in milk was investigated. The effect of cereals on quality of curd yogurt (apparent viscosity, sensory property) was also examined. Addition of cereals markedly stimulated acid production by lactic acid bacteria. Among three organisms tested, L. acidophilus produced more acid than others. Apparent viscosity of curd yogurt added with corn was the highest while that with barley was the lowest. Curd yogurt fermented with L. acidophilus showed characteristics of thioxotropic flow. Apparent viscosity of curd yogurt added with cereal markedly increased between 6 and 24 hours of fermentation. Sensory property of curd yogurt added with wheat was judged as better than reference sample, but that with barley was lodged as the worst among all samples.

• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.4
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• pp.695-700
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• 1996

In other to produce vinegar using maesil, acetic acid bacteria were selected from several conventional vinegars, and total 16 acetic acid producing bacterial strains were isolated. Among the isolated strains, a strain was selected from the medium with maesil juice which showed the highest productivity of acetic acid. The strain was identified as Acetobacter sp. VC-2 and it's cultural characteristics were also investigated in the batch shake flasks. The medium containing 2% acetic acid, 6% ethanol, 0.2% glucose, 0.3% yeast extract and 30% maesil juice was suitable for acetic acid production with Acetobacter sp. VC-2 at 3$0^{\circ}C$. The acidity of culture medium was reached to 6.5% after 8 days shaking cultivation at 3$0^{\circ}C$. The main components of organic acids were acetic, citric, malic and tartaric acid, and they were 4.28, 1.38, 0.48 and 0.30%, respectively.

• Journal of Food Hygiene and Safety
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• v.14 no.4
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• pp.352-357
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• 1999

Changes in titratable acidity, viable cells and sensory properties of curd yogurt during lactic fermentation in milk added with mugwort extract have been studied. Milk added with 5%, 10％, 15％ or 20% of mugwort extract was fermented with single or mixed culture of Lactobacillus bulgaricus and Streptococcus thermophilus for 24 hours. Addition of mugwort extract markedly stimulated the acid production and propagation of lactic acid bacteria. Among the organism tested, the mixed culture of Lactobacillus bulgaricus and Streptococcus thermophilus produced the highest amount of acid, and Lactobacillus bulgaricus showed the highest number of viable cell counts. Sensory property of curd yogurt added with mugwort extract was evaluated as better than reference sample(milk yogurt). The sample prepared by fermenting milk containing mugwort extract at 5% level with Lactobacillus bulgaricus showed the most favorite characteristics.

• Journal of dental hygiene science
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• v.7 no.1
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• pp.9-12
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• 2007

Streptococcus mutans is the major causative factor in dental caries and has been known to induce dental caries by the process of initial attachment proliferation and acid production. The pH of Streptococcus mutans(S. mutans) media and glucosyltransferase(GTase) activity were determined to evaluate the anticariogenic activity of Dioscorea batatas and Prunella vulgaris hexane fraction. In the experiment of hexane fraction of Dioscorea batatas, the relative growth ratio(RGR) against Streptococcus mutans (S. mutans) was determined as 93% in concentration of 0.125 mg/ml, 100% in 0.25 mg/ml. The hexane fraction of Prunella vulgaris revealed relative growth ratio(RGR) against Streptococcus mutans (S. mutans) as 86% in concentration of 0.25 mg/ml, 100% in 0.5 mg/ml. The relative growth ratio(RGR) against of hexane fraction were determined as 92% in concentration of 0.25 mg/ml, 100% in 0.5 mg/ml. The acidities were pH 7.2 on Dioscorea batatas and 7.0 on Prunella vulgaris in 2.0 mg/ml in contrast to pH 5.6 on Dioscorea batatas and 5.2 on Prunella vulgaris in control. The inhibitory effect to activity revealed 35% on Dioscorea batatas and 25% on Prunella vulgaris in 2.0 mg/ml. The inhibitory effect of Dioscorea batatas was more potent than Prunella vulgaris.

• 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 Agricultural Science
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• v.11 no.1
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• pp.34-44
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• 1984

This experiment was carried out to obtain the fundamental data for development of digestibility and quality enhanced product of soy yogurt. Soy yogurt was processed from raw materials of soybean, defatted soybean and sprouted soybean which inoculated with Lactobacillus acidophilus and Bifidobacterium bifidum as a starter. Changes of chemical compositions, viable cell count and saccharides during processing were investigated including acceptibility of manufactured products. The results were summarized as follows; 1. Defatted soy milk ferment ed with Lactobacillus acidophilus was showed the greatest initial acid productivity and sprouted soy milk was showed the greatest growth of Loctobacillus acidophilus. 2. Acid production was accelerated when 2% glucose was used in soy milk. 3. Addition of reconstituted skim milk in soy milk and defatted roy milk increased acid production but was not showed the effect in the sprouted soy milk. 4. Sprouting soybean, the contents of raffinose and stachyose were decreased but those of glucose was increased. 5. When soy milk was fermented with Lactobacillus acidophilus. the contents of raffinose and stachyose were decreased. 6. As a result of panel test, sprouted soy yogurt which was produced by addition of reconstituted skim milk of 10% showed the greatest flavor and tastes.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.12
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• pp.1431-1434
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• 2014

The thermal barrier coating (TBC) applied to a gas turbine can be damaged by repeated thermal fatigue during operation, so an evaluation of its durability is needed. Thermally grown oxide (TGO) is generated inside the TBC in a high-temperature environment. The growth of TGO is known to be the main cause of damage to the TBC. Therefore, the durability of TBC should be evaluated according to the growth of TGO. In this research, Kim et al.'s work on the growth of TGO with aging was used as a basis for finite element analysis. The relationship between stress and aging was derived from the finite element analysis results. The durability of the TBC with aging was evaluated through a comparison between the results of the finite element analysis and a bond strength test.

• Korean Journal of Food Science and Technology
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• v.21 no.3
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• pp.379-386
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• 1989

The soy milk prepared from soy protein concentrate was treated with microbial protease or papain. Growth and acid production by Lactobacillus acidophilus in soy milk containing partially hydrolyzed proteins were investigated. Sensory evaluation of yogurt beverage prepared from protease treated soy milk was also performed. Protease treatment of soy milk enhanced acid production by lactic acid bacteria, particularly in case of microbial pretense and simultaneous treatment by two types of protease showed synergistic effect. pH and number of viable cells were not affected markedly by pretense treatment. Microbial pretense treatment up to 15 minutes or papain treatment up to 45 minutes enhanced acid production, but further treatment up to three hours did not affect the acidity markedly. rho sensory evaluation showed that overall acceptability and taste of soy yogurt beverage were slightly improved when soy milk was treated with microbial pretense of 0.2% or papain of 0.2%. The amount of non-protein nitrogen considerably increased by pretense treatment of 15 minutes and it increased gradually by further treatment up to three hours.

• Korean Journal of Food Science and Technology
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• v.27 no.4
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• pp.458-463
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• 1995

A curd yogurt was prepared from milk added with skim milk powder or egg white powder(EWP). The effects of EWP addition on growth and acid production by lactic acid bacteria in milk were studied. The effects of EWP addition on quality of curd yogurt in point of apparent viscosity, sensory property and volatile aroma compounds were also investigated. Addition of PAT markedly stimulated acid production by lactic acid bacteria and stimulating effect of EWP on acid production was proportional to the amount of addition. Apparent viscosity of curd yogurt added with EWP was generally higher than that of control. Curd yogurt fermented with L. acidophilus showed thixotropic characteristics. Sensory property of curd yogurt added with EWP was evaluated as better than reference sample and sample added with EWP at 2% level was evaluated as better than other samples. Acetone, ethanol, diacetyl, butanol and acetoin were detected by gas chromatographic analysis.