• Food Science of Animal Resources
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• v.23 no.3
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• pp.193-199
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• 2003

In order to investigate the meat tenderizing effects of pear, pineapple and kiwifruit, crude protease was prepared from each fruit and treated with actomyosin in a single manner or mixed type in several combination. Actomyosin was incubated with various proteases for 24 hrs under three different pH condition, and its degrading performance was evaluated by the SDS-PAGE. Pear extract showed an active degrading activity for actomyosin at pH 5.3 and 7.0. But, little actomyosin degradation was observed at pH 8.0. Actomyosin was strongly degraded by the treatment of protease from pineapple at all different pHs(5.3, 7.0 and 8.0). Kiwifruit protease extract has shown actomyosin degradation activity 1hr after treatment at pH 5.3 and pH 7.0. Meanwhile, the mixture of pear and pineapple extracts(l:l, w/w) showed much more degradation than the results of singular manner treatment at pH 5.3 and 7.0. When the pear protease was mixed with kiwifruit protease(l:l, w/w), the performance of actomyosin degradation was similar to the results of each single protease treatment. When the mixture was made of pineapple and kiwifruit extracts, actomyosin degradation was almost the same as the result of treatment of pineapple protease only. When those three proteases were mixed together(l:l:l, w/w/w), actomyosin degrading activities was in time dependent manner at pH 5.3. In summary, pear protease can be used potentially as a meat tenderizer when it was mixed with pineapple or kiwifruit rendering proper tenderization of the meat.

• Korean Journal of Food Science and Technology
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• v.16 no.4
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• pp.423-428
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• 1984

Changes in viscosity of soymilk were evaluated as affected by solid concentration, temperature, pH and sugar addition. Soybeans were soaked, ground with boiling water, and filtered followed by boiling for 30 min for soymilk preparation. It was found that viscosity increased exponentially as solid concentration increased while the raise of temperature caused exponential decrease in it. A minimum viscosity was ovserved at pH 6.5 in the range of pH 5.0-8.0. The effects of solid concentration and pH on viscosity were reduced as the measuring temperature increased. Addition of sucrose up to 9% showed little effect on viscosity with showing a tendency of increase.

• Journal of Food Hygiene and Safety
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• v.17 no.3
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• pp.117-123
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• 2002

The five main green tea catechin components such as (+)-catechin, (-)-epicatechin, (-)-epigallocatechin, (-)-epicatechin gallate, and (-)-epigallocatechin gallate were analyzed quantitatively from commercial green tea by HPLC. Amounts of catechins decreased in the following order : (+)-catechin > (-)-epigallocatechin gallate >(-)-epigallocatechin >(-)-epicatechin >(-)-epicatechin gallate. In this study, the stability of the following green tea catechins to pH in the range from 3 to 11 was studied using of ultraviolet spectroscopy : (+)-catechin, (-)-epicatechin, (-)-epicatechin gallate, and (-)-epigallocatechin gallate. This study demonstrated that green tea catechins were not stable at high pH and that the pH-, and time-dependent spectral alternatives were not reversible In conclusion, low pH is important to maintain the efficient utilization of green tea catechins.

• Korean Journal of Agricultural Science
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• v.24 no.2
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• pp.156-169
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• 1997

This experiment was carried out to exame the effects of sweeteners, sucrose(2.0~10.0%), aspartame(0.01~0.05%) and oligosaccharide(3.6~11.6%) on the fermentation of yoghurts by single or mixed culture (Lact. bulgaricus and Str. thermophilus). The acidity, pH and number of lactic acid bacteria in yoghurts added different level of sweeteners were examined by the fermentation time. The results were summarized as follows; 1. The acidity increased and the pH decreased more rapidly by 4.0% sucrose and 5.6% oligosaccharide. By the addition of 8.0% sucrose and 9.6% oligosaccharide the acidity and pH of yoghurts were changed less significantly. 2. The number of Lact. bulgaricus and Str. thermophilus increased more rapidly by 4.0% sucrose and 5.6% oligosaccharide and increased slowly above those levels. 3. Aspartame as a sweeteners did not affect on the acidity, pH and number of lactic acid bacteria in yoghurts. 4. The number of lactic acid bacteria, acidity and pH in yoghurts added sucrose and oligosaccharide were affected more by single culture than by mixed culture.

• Journal of Environmental Impact Assessment
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• v.19 no.1
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• pp.39-47
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• 2010

In order to examine the effect of impermeable surface (rooftop, outdoor parking lot) and rainwater infiltration facilities on runoff pH, pH was measured. pH measurement spots were splash blocks accepted roof runoff of 3 sites, infiltration boxes and trenches accepted parking lot runoff and plastic rainwater harvesting facility accepted roof runoff. These measurements were operated at 3 housing complexes from 2006 to 2009. The rainwater runoff pH was influenced by the quality of the runoff surface material (concrete), the age of the building, waterproofing methods according to each housing site, antecedent rainfall conditions and others. Rain garden, infiltration boxes and trenches decreased the alkalinity of runoff by detention and infiltrating the roof and outdoor parking lot runoff. These results mean that decentralized rainwater management facilities of housing complexes can reduce effect on the outskirt aquatic ecosystem by the accumulation of substances causing pH rising in the infiltration facilities and rain garden.

• Korean Journal of Food Science and Technology
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• v.29 no.6
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• pp.1222-1227
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• 1997

Effects of the physical properties of solvent system such as pH and polarity change by salt addition in solvent system were investigated by using high speed countercurrent chromatography apparatus (Model CCC-1000, Pharm-Tech Research Corp. USA). The changes of pH and interfacial tension in solvent system of high speed countercurrent chromatography did not significantly affect on retention of stationary phase, but induced remarkable changes in the partition coefficient of ginkgo flavonoids, kaempferol, quercetin and isorhamnetin. The partition coefficients of ginkgo flavonoid standard increase with an increased pH of solvent system and quercetin sharply increased at pH 10.0. Retention of stationary phase decreases with an increased concentration of KCl in butanol of solvent system. Interfacial tension between two phase in solvent system of hexane increases with an increased concentration of KCl. The polarity of solvent system significantly changes the partition coefficients of ginkgo flavonoid.

• Korean Journal of Microbiology
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• v.28 no.2
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• pp.162-168
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• 1990

The aims of the present study were to evaluate the effects of culture conditions on the biosynthesis of extra-cellular alkaline protease in Streptomyces sp. The formation of aerial mycelia and spores were compared with the protease production in order to know the relations between the alkaline protease and the cell differentiation. As results, it was found that substrate concentration was very critical to regulate the formation of the protease, aerial mycelia, and spores, which were resulted from the changes of culture pH to acid. When the culture pH was adjusted with phosphate buffer from pH 6 to pH 9, the alkaline protease production was increased as the culture pH increased whereas aerial mycelia and spore formation were reversely related to the culture pH. Therefore, it was thought that the culture pH was an important factor to regulate the alkaline protease synthesis.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.6
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• pp.143-150
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• 2012

바이오에탄올 생산공정은 당 (Sugar)을 기반으로 하는 공정과 합성가스를 이용하는 공정으로 분류할 수 있다. 이 가운데 합성가스를 이용하는 공정은 촉매를 이용한 화학적 공정과 혐기성 발효에 의한 생물학적 공정의 두 가지로 나뉜다. Clostridium ljungdahlii는 일산화탄소와 수소가 주요 성분으로 구성되는 합성가스를 이용하여 에탄올과 아세트산을 생산할 수 있는 균주 중의 하나로 알려져 있다. 합성가스 발효공정에서 pH는 미생물의 증식과 에탄올 등의 생산에 아주 중요한 요인 중의 하나이다. 본 연구에서는 pH 조건이 미생물의 생장과 에탄올 생산성에 미치는 영향을 조사하였다. C. ljungdahlii 배양은 엄격한 혐기성 조건에서 100 ml의 serum bottle과 pH 제어가 가능한 반응기를 이용한 실험결과, 회분식 배양 조건에서는 미생물의 생장과 에탄올 생산을 위한 최적 초기 pH는 7.0로 나타났다. 미생물 농도는 0.57 g/L, 에탄올 농도 0.91 g/L로 나타났다. pH 4.5 이하에서는 미생물의 생장이 멈추는 것으로 나타났다. pH 제어가 가능한 생물반응기에서는 pH 6.0 일때 에탄올 생산량이 pH 7.0 일때 보다 높게 나타났다. 일정 수준의 미생물 농도를 유지한 조건에서 합성가스를 기포식으로 주입하고 pH 5.9에서 5.4까지 제어하였을 때 미생물량과 에탄올 농도가 증가하였다. 60 시간이 지난 후에 미생물의 농도는 0.498 g/L, 에탄올은 1.056 g/L까지 이르렀다.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2000.05a
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• pp.126-127
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• 2000

Fe(III) 응집제는 pH 5～9범위에서 Al(III)계 응집제보다 보다 우수한 응집효과를 보였으며 또한 pH의 영향을 거의 받지 않는 것으로 나타났다. 잔류 Fe의 경우 응집제 주입농도와 pH 증가에 영향을 거의 받지 않고 저농도의 잔류 Fe농도를 나타낸 반면, Al(III) 응집제는 잔류 Al의 급격한 증가를 나타내었다.

• Journal of the Korean Geotechnical Society
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• v.23 no.8
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• pp.97-106
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• 2007

In this study, experiments are conducted to find out the effect of waste leachate on landfill clay liner system. Tensile test, hydrometer analysis and crack pattern test were conducted on sand-bentonite mixtures with different pH values of water. The tensile strength of specimen compacted with pH 9 of water is smaller than that of specimen compacted with for pH 3 and 6 of water. That is, the higher the pH value, the smaller the tensile strength, because a higher pH solution decreases flocculation phenomenon. The percent finer also increased with high pH value in particle size distribution of fine grained soil (<0.075 mm), because the velocity of particles settling decreases. This trend becomes the clearer as the content of bentonite, becomes the larger, because the higher pH value decreases flocculation structure of fine soils. The results of the crack pattern tests also showed the effect of pH values of water.