• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2011년도 춘계학술발표회 논문집
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• pp.93-99
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• 2011

Proton-NMR spectroscopic method was applied to kinetics study of concentrated sulfuric acid hydrolysis reaction. Xylan was used as model compounds. Without neutralization steps in proton-NMR methods, this analysis method is valid for analysis of xylose, furfural and formic acid in acid hydrolyzates.

• 한국응용과학기술학회지
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• 제6권2호
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• pp.59-65
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• 1989

The rate constants of the hydrolysis of cinnamanilide derivatives were determined UV spectrometry in $H_2SO_4\;(5{\sim}20N)$, NaOH($5{\sim}11N)\;at\;50{\sim}110^{\circ}C$ and rate equation could be applied over a strong acid and strong base were obtained. Final product of the hydrolysis was a cinnamic acid. The ${\rho}$ values obtained from the slope of linear plots of log $k_{abs}$ vs. Hammet $t{\sigma}$ constants were slightly negatives, Substituents on cinnamanilide showed a relatively small effect, with hydrolysis facilitated be electron donating group. Activation energy(Ea)was also calculated for the hydrolysis of the cinnamanilide. From this reaction rate equation, substituent effect and experimental of rate constants, that the hydrolysis of cinnamanillde was Initiated by the netural molecule of $H_2O$ which do not dissociate at strong acid, and proceeded by hydroxide ion at strong base.

• Elastomers and Composites
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• 제55권2호
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• pp.128-136
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• 2020

The hydrolysis mechanisms as well as the hydrolysis measurement technique and its practical applications in material manufacturing fields are revised. This chapter, Part 1, elaborates the theoretical aspects of the hydrolysis mechanism. Acid-catalyzed and base-catalyzed hydrolysis mechanisms are reviewed. The quantitative analysis method based on the SIM technique using py-GC-MS is reviewed. Examples of hydrolysis of alkoxysilane in elastomer composites currently used in the industry and hydrolysis of amine in plastic composites are shown. Moreover, Part 2 discusses the mechanical property changes in elastomer and plastic composites after hydrolysis.

• Natural Product Sciences
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• 제14권3호
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• pp.187-191
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• 2008

The contents of isoflavones and 1,1-diphenyl-2-picryl hydrazyl (DPPH) free radical scavenging activities were determined in flowers (Puerariae Flos) and roots (Puerariae Radix) of Pueraria thunbergiana to differentiate both pharmacochemical or pharmacognostical usage of both oriental medicinal drugs. The tectorigenin contents in flower before and after acid hydrolysis were shown to be 17.10 ${\mu}mole\;g^{-1}$ and 49.58 ${\mu}mole\;g^{-1}$, respectively, analyzed by HPLC. However, the root displayed much less content of tectorigenin even after acid hydrolysis (6.56 ${\mu}mole\;g^{-1}$) than in the flower. Acid hydrolysis made glycitin and tectoridin of the isoflavone glycosides almost disappear in the flower and root. DPPH assay results demonstrated that acid hydrolysis of both extracts or both glycosides should increase free radical-scavenging activities due to the increase of isoflavone contents. It is also suggested that the flower had much higher concentration of isoflavonoids than in the root.

• KSBB Journal
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• 제20권2호
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• pp.129-132
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• 2005

본 연구는 헛개열매 추출물의 pH를 산성으로 조절한 산 가수분해 방법에 의하여 헛개열매 추출물에 배당체 형태로 존재하는 알코올분해 효능을 가진 생리활성물질 ((+)-dihydromyricetin)의 양을 증가시켰다. 반응온도 $80^{\circ}C$, 반응시간 4hr, 반응 pH 2.0에서 $124\%$의 알코올분해 효능이 증가하여 최적임을 알 수 있었다. 산 가수분해 전 후에 생리활성물질인 (+)-dihydromyricetin의 양이 $30\%$ 증가함을 알 수 있었으며, 또한 헛개열매 추출물에 포함되어 있는 고분자 물질이 분해됨을 확인할 수 있었다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제3권1호
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• pp.35-39
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• 1998

An enzymatic process was developed to produce protein hydrolysater form defatted soya protein. Various unit operations were tried, and the effects of pre- and post-treatments on the product characteristics such as degree of hydroylsis (DH), free amino acid content (%FAA) and average molecular weight (MW) were investigated. The use of acid washes showed no difference in %DH. Increasing pH during pre-cooking gave lower %DH. Alkaline cooking made too much insoluble protein, thus the protein yield was too small. A better hydrolysis with more acceptable taste was obtained when the combination of Neutrase/Alcalase/Flavourzyme was used in place of Alcalase/Flavourzyme combination; Untoasted defatted soya was more effective on the proteolysis than toasted one. The MW of the evaporated and spray dried product was higher than that of undried product, due to precipitation of low-solubility components. When ultrafiltration and the product concentration carried out the product separation by reverse osmosis, the solubility and the taste of the product were improved. The difference between enzyme hydrolysate and acid hydrolysate was significant in free amino acid composition, especially in tyrosine, phenylalanine, glutamine and asparagine.

• KSBB Journal
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• 제23권6호
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• pp.509-512
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• 2008

원료물질인 대두유를 산가수분해하여 지방산의 함량을 분석한 결과 linoleic acid, oleic acid, palmitic acid, stearic acid의 함량순으로 분석되었다. 동일한 조건하에 대두유의 가수분해반응 전화율을 조사한 결과 Candida rugosa와 Candida cylindracea 에서 유래된 효소인 CR-E와 CC-E가 Lipase 16, Novozyme 871과 Lipolase-100 L보다 2배이상 높았다. 따라서 CR-E와 CC-E를 선정하여 반응조건에 대한 실험을 수행하였다. CR-E와 CC-E의 경우 비슷한 결과를 보여, pH $3{\sim}6$, $35-45^{\circ}C$, 물과 대두유의 중량비가 3.3 이상이었을 때가 최적인 반응조건이었으며 95% 이상의 높은 전화율을 나타내었다.

• Journal of the Korean Wood Science and Technology
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• 제37권6호
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• pp.578-584
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• 2009

백합나무 목분으로 고농도 단당류를 생산하기 위하여 진한 황산을 사용하는 산 가수분해 특성을 연구하였다. 목분과 황산의 비율을 달리하거나 2차 가수분해의 온도와 시간을 달리하여 당화액 제조의 최적 조건을 탐구한 결과, 1차 가수분해의 목분과 72% 황산 비율은 1 : 2.61(w/w)였으며, 2차 가수분해 온도와 시간은 $105^{\circ}C$에서 70분 가수분해 조건이었다. 이때 생성된 당화액의 농도는 glucose가 44.8 g/L였고 xylose는 25.2 g/L였다. 산 가수분해를 통하여 얻어진 당화액을 발효할 때 발효 저해물질로 알려진 furfural, 5-HMF (5-hydroxymethylfurfural), 저분자량 페놀성 화합물들이 생성되었는데 furfural과 5-HMF는 2차 가수분해 온도가 높아짐에 따라, 그리고 반응시간이 길어짐에 따라 생성량이 증가하였다. $110^{\circ}C$ 2차 가수분해 조건에서 반응시간이 40분을 지남에 따라서 xylose농도는 감소하였고 glucose 농도는 일정하였는데, xylose는 생성속도보다 furfural로 전이 속도가 더 빠른 것으로 생각되고, glucose의 경우 생성속도와 5-HMF로 전이속도가 비슷하여 농도가 일정하게 나타났다.

• Archives of Pharmacal Research
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• 제12권2호
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• pp.68-72
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• 1989

The hydrolysis rates of ester and amide derivatives of 20-dihydroprednisolonic acid were measured in rat serum and liver homogenate. The hydrolysis rate of the esters in serum was found to be faster than that in liver homogenate on the basis of blood volume and liver weight, while the amide derivatives showed much slower change. And it is also found that the size of substituents at C-21 and C-20 configuration expressed considerable effects on the hydrolysis rate of these derivatives.

• Biotechnology and Bioprocess Engineering:BBE
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• 제2권2호
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• pp.101-104
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• 1997

Lactic acid production from ${\alpha}$-cellulose by simultaneous saccharification and fermentation (SSF) was studied. The cellulose was converted in a batch SSF using cellulase enzyme Cytolase CL to produce glucose sugar and Lactobacillus delbrueckii to ferment the glucose to lactic acid. The effects of temperature, PH, yeast extract loading, and lactic acid inhibition were studied to determine the optimum conditions for the batch processing. Cellulose was converted efficiently to lactic acid, and enzymatic hydrolysis was the rate controlling step in the SSF. The highest conversion rate was obtained at 46$^{\circ}C$ and pH 5.0. The observed yield of lactic acid from ${\alpha}$-cellulose was 0.90 at 72 hours. The optimum pH of the SSF was coincident with that of enzymatic hydrolysis. The optimum temperature of the SSF was chosen as the highest temperature the microoraganism could withstand. The optimum yeast extract loading was found to be 2.5g/L. Lactic acid was observed to be inhibitory to the microorganisms' activity.