• Bulletin of the Korean Chemical Society
• /
• 제23권9호
• /
• pp.1218-1242
• /
• 2002

Photochemical reactions of aromatic carbonyl compounds with silyl ketene acetals have been explored. Irradiation of acetonitrile or benzene solutions containing aryl aldehydes or ketones in the presence of silyl ketene acetals is observed to promo te formation of ${\beta}-hydroxyester$, 2,2-dioxyoxetane and 3,3-dioxyoxetane products. The ratios of these photoproducts, which arise by competitive single electron transfer (SET) and classical Paterno-Buchi mechanistic pathways, is found to be dependent on the degree of methyl-substitution on the vinyl moieties of the ketene acetals in a manner which reflects expected alkyl substituent effects on the oxidation potentials of these electron rich donors. An analysis of the product distribution arising by irradiation of a solution containing butyrophenone (6) and the silyl ketene acetal 9, derived from methyl isobutyrate, provides an estimate of the rate constants for the competitive Norrish type Ⅱ, SET and Paterno-Buchi processes occuring. Finally, sequences involving silyl ketene acetal-aryl aldehyde or ketone photoaddition followed by 2,2-dioxyoxetane hydrolysis represent useful procedures for Claisen-condensation type, ${\beta}-hydroxyester$ synthesis.

• 한국식품과학회지
• /
• 제37권3호
• /
• pp.345-351
• /
• 2005

본 연구에서는 시판되고 있는 카제인 나트륨, 유청 단백질, 탈지분유 및 전지분유에 TGase를 첨가하여 이화학적 특성 및 식품첨가물 소재로서의 기능적 특성 등을 조사하였다. 카제인 나트륨의 경우 TGase효소 반응 후 pH 2, pH 4와 알칼리 범위에서, 유청 단백질은 pH 4에서 용해성이 향상되었고 탈지분유에서는 pH 4와 전지분유에서는 모든 pH 범위에서 용해성이 향상되었다. TGase를 첨가한 우유 단백질과 우유 분말 제품이 무첨가군에 비하여 pH 의존적으로 용해성, 유화활성 및 거품형성 등에 기능적 특성이 부분적으로 우수함을 알 수 있었다. 또한 TGase 첨가에 따라 일반성분의 변화가 없었으며 인체내 소화효소에 의해 가수분해가 용이하였고 점도의 증가가 관찰되었다. TGase를 첨가한 제품은 이화학적, pH 및 반응시간 등의 특징에 의하여 영향을 받으므로 식품에 응용할 경우 기능성들이 합리적으로 조절되도록 함이 바람직하다.

• 한국미생물·생명공학회지
• /
• 제7권3호
• /
• pp.141-147
• /
• 1979

Aspergillus nidulans가 생산하는 naringinase를 DEAE-Sephadex A-25를 사용하여 이온결합법으로 고정화시키는 조건과 그 고정화효소의 성질 및 column reactor 에서의 연속 반응에 대하여 연구 검토한 것을 요약하면 다음과 같다. 고정화 효소를 조제할 때에 효소가 담체에 흡착되는 최적 pH는 6.0이었고 건조된 담체 1g에 대해 이상적인 수용성 효소의 량은 110 units이였다. 고정화 naringinase의 반응 최적 온도와 pH 는 각각 5$0^{\circ}C$와 7.0이며, 그 pH 안정성과 열 안정성은 수용성 효소보다 모두 높았다. 고정화 naringinase의 활성화 에너지는 Arrhenius plot에 의해 7.96kca1/mo1e이었고 겉보기 Km 값은 5.88$\times$$10^{-4}$M 이었다. 고정화 naringinase를 column 내에서 연속 반응시킬 때 Bar-Eli등의 Michaelis-Menten식의 적분형을 변형하여 유속과 가수분해도의 관계를 검토한 결과, 유속이 증가하면 가수분해도가 감소되었고 동시에 겉보기 Km값도 감소하였다. 또한 반응량 (colum reaction capacity)은 유속이 증가함에 따라서 서서히 감소하였다.

• 한국식품영양과학회지
• /
• 제25권4호
• /
• pp.608-616
• /
• 1996

참치 가공 부산물로 부터 유용한 식량소재를 찾기위한 목적으로 상업용 단백질 분해효소를 이용하여 반응표면분석법에 의한 최적화한 조건에서 참치 가수 분해물을 제조한 결과를 요약하면 다음과 같다. 8종의 상업용 단백질 분해효소에서 가격에 대한 효소활성도와 관능검사 결과치로부터 Pretease P가 최적 효소로 선정되었으며, 참치 가공 부산물 가수분해 과정중 원료 자체의 가수분해효과는 없었다. 반응표면분석 결과 결정계수(0.9460) 및 적합결여검증(P>0.1)을 통해, 본 실험의 디자인이 만족하게 설계되었음을 알 수 있었고 일차식 및 이차식에서는 p<0.05% 수준에서 유의하였다. 다중회귀분석 및 능선분석 결과, 가수분해물 제조를 위한 최적 조건은 pH 7.2, 반응온도 $51^{\circ}C,$ 기질농도 33.3%, 기질에 대한 효소농도 0.48%에서 3.94시간 가수분해시 킬 때이며, 이때의 가수분해율은 64.88%였다.

• 한국수산과학회지
• /
• 제37권5호
• /
• pp.359-365
• /
• 2004

To study the lipid adsorption characteristic of chitosans with different molecular weights and the degrees of deacetylation, in vitro test and near-infrared (NIR) spectroscopic analysis have been performed for the measurement of lipid adsorption characteristics of chitosan. The degrees of deacetylation in chitosans were $70{\%},\;85{\%}\;and\;92{\%}$ at different deacetylation times (1 hr, 2 hrs, 3 hrs), respectively. The molecular weight of each chitosan was controlled by enzymatic hydrolysis, and then the molecular weight of the chitosan was 4 kDa. The bulk density, water holding capacity and fat binding capacity of each chitosan powder were $96.2-504.0{\%},\;374.4-1217.9{\%},\;and\;307.0-659.3{\%}$, respectively. The higher molecular weight of chitosan was exhibited the lower bulk density and the higher water and fat binding capacities. Bindinf capacities of chitosan powders to bile salts, cholesterol and linoleic acid were $41.2-63.3{\%},\;40.8-67.4{\%},\;42.6-72.6{\%}$, respectively. In NIR spectrum of lipid adsorbed chitosan the occurrence static eletronical binding between chitosan and lipid was identified by NIR spectrum peak induced from combination of carboxylic group in lipid and amino group in chitosan. In conclusion, the higher degree of deacetylation and molecular weight of chitosan showed the higher lipid binding capacity and the lipid adsorption of chitosan were occurred by combination of carboxylic group in lipids and amino group in chitosan.

• Applied Biological Chemistry
• /
• 제30권3호
• /
• pp.234-241
• /
• 1987

어육(魚肉) 단백질(蛋白質)의 기능성(機能性)을 개선(改善)하기 위해 정어리 분말단백질(粉末蛋白質)의 pepsin 가수분해물(加水分解物)을 이용(利用)하여 plastein을 합성(合成)하기 위한 반응조건(反應條件)을 검토(檢討)하였다. Plastein의 합성조건(合成條件)은 papain 및 pepsin의 경우 pH는 각각(各各) 6, 4, 기질농도(基質濃度)는 각각(各各) 50%, 40%, 반응시간(反應時間) 및 효소농도(酵素濃度)는 각각(各各) 2시간(時間), 1%였으며 반응온도(反應溫度)는 papain 및 pepsin 모두 $50^{\circ}C$였다. 기질(基質)의 가수분해도(加水分解度)가 60% 이상(以上)에서 plastein 합성반응(合成反應)이 이루어졌으며 가수분해도(加水分解度)가 77.2% 이상(以上)이었을 때 plastein 생성량(生成量)이 높았다. 단백질(蛋白質) 함량(含量)은 50% ethanol 침전(沈澱) plastein이 90% 정도(程度)로 10% TCA 침전(沈澱) plastein의 74%에 비(比)해 높았으나 회분(灰分) 함량(含量)은 10% TCA 침전(沈澱) plastein이 14.4%로 50% ethanol 침전(沈澱) plastein의 1.2%보다 월등히 높았다. 수율(收率)은 papain의 경우 10% TCA 침전(沈澱) plastein 및 50% ethanol 침전(沈澱) plastein이 각각(各各) 49.5%, 43.6%로서 pepsin plastein의 45.3%, 41.0%보다 약간 높았다.

• 한국식품영양학회지
• /
• 제11권3호
• /
• pp.272-277
• /
• 1998

탈취온도를 상이하게 처리한 옥수수기름들로부터 정유성분을 추출하여 이의 favor 성분을 GC로 분리 정량하였다. Flavor성분으로는 8종의 aldehydes를 포함하여 총 16종이 검출되었으며, 주요 flavor성분은 propane, pentane, hexanal 등으로 이는 전체의 70~75%를 차지하였다. 탈취온도가 상승할수록 ethane 및 8종의 propane, pentane, hexane, octane, pentyl furna 함량은 뚜렷한 감소현상을 나타내었다. 한편, 총 flavor 성분함량은 245$^{\circ}C$ 처리군에서 가장 낮아 특이성을 나타내었으며, 탈취온도의 상승에 따라 aldehydes 함량이 비례적으로 증가하였는데, 이는 탈취과정 중 stripping steam, 진공도 등의 영향으로 인한 부분인 자동산화, 분해, 중합, 가수분해 등의 부반응에 기인하는 것으로 사료된다. 따라서, 이취물질의 극소화를 위하여는 지나친 고온탈취를 억제하는 것이 바람직하다는 결론을 얻었다.

• Journal of Microbiology and Biotechnology
• /
• 제15권5호
• /
• pp.1125-1129
• /
• 2005

Cloning of a 6.6-kb BamHI digested chromosomal DNA from S. griseus IFO13350 revealed the presence of an additional gene encoding a novel trypsin-like enzyme, named SprU. The SprU protein shows a high homology ($79\%$ identity, $88\%$ similarity) with the SGT protease, which has been reported as a bacterial trypsin in the same strain. The amino acid sequence deduced from the nucleotide sequence of the sprU gene suggests that SprU is produced as a precursor consisting of an amino-terminal presequence (29 amino acid residues), prosequence (4 residues), and mature trypsin consisting of 222 amino acids with a molecular weight of 22.94 kDa and a calculated pI of 4.13. The serine, histidine, and aspartic acid residues composing the catalytic triad of typical serine proteases are also well conserved. When the trypsin activity of the SprU was spectrophotometrically measured by the enzymatic hydrolysis of the artificial chromogenic substrate, N-${alpha}$-benzoyl-DL-arginine-p-nitroanilide, the S. lividans transformant with pWHM3-U gave 3 times higher activity than that of control. When the same recombinant plasmid was introduced into S. griseus, however, the gene dosage effect was not so significant, as in the cases of other genes encoding serine proteases, such as sprA, sprB, and sprD. Although two trypsins, SprU and SGT, have a high degree of homology, the pI values, the gene dosage effect in S. griseus, and the gene arrangement adjacent to the two genes are very different, suggesting that the biochemical and biological function of the SprU might be quite different from that of the SGT.

• 대한화장품학회:학술대회논문집
• /
• 대한화장품학회 2003년도 IFSCC Conference Proceeding Book I
• /
• pp.178-191
• /
• 2003

OMC is essentialiy necessary compound in sun goods as organic UV protecting products. But the skin-trouble problem is raising because of skin penetration of OMC. In this study, non-capsulated pure OMC was compared with Organic-Inorganic-Nano-hybrid OMC for skin penetration force and SPF degree. Organic- Inorganic Nano-Hybrid OMC is OMC trapped in the pore of the mesoporous silica synthesized by the sol-gel method after OMC is nanoemulsified in the system of the hydrogenated Lecithin/ Ethanol/caprylic/capric triglyceride/OMC/water. OMC- nano- emulsion was obtained by a microfluidizing process at 1000bar and then micelle size in the nanoemulsion solution is 100-200nm range. Mesoporous silica nano-hybrid OMC was prepared by the process; surfactant was added in dissolved OMC-Nanoemulsion, then the rod Micelle was formed. OMC-nanoemulsion was capsulated in this rod Micelle and then silica precursor was added in the OMC-nanoemulsion solution. Through the hydrolysis reaction of the silica precursor, mesoporous silica concluding OMC-Nanocapsulation was obtained. The nano-hybrid surface of this OMC-Nanoemulsion-Inorganic system was treated with polyalkyl-silane compound. OMC-Mesoporous silica Nano-hybrids coated with polyalkyl-silane compound show the higher sun protecting factor (SPF Analyzer: INDEX 10-15) than pure OMC and could reduce a skin penetration of OMC. The physico-chemical properties of these nano-hybrids measured on the SPF index, partical size, strcture, specific surface area, pore size, morphology, UV absorption, rate of the OMC dissolution using SPF Analyzer, Laser light scattering system, XRD, BET, SEM, chroma Meter, HPLC, Image analyzer, microfluidizer, UV/VIS. spectrometer.

• Biotechnology and Bioprocess Engineering:BBE
• /
• 제3권2호
• /
• pp.103-108
• /
• 1998

A hydrophobic substrate triolein was hydrolyzed by lipase in a mono-phase reaction system containing cyclodextrin(CD) as emulsifier. The triolein was transformation to an emulsion-like state in the CD containing reaction system in contrast to the oil-droplet like state without CD due to the formation of an inclusion complex between the lipids and CDs. The hydyrolysis reaction increased substantially in the CD containing reaction system, and the optimum reaction conditions including the amount of lipase, ${\beta}$-CD concentration, and mixing ratio of triolein and ${\beta}$-CD, were determined. The performance of the enzyme reaction in a mono-phase reaction system was compared with that of a two-phase reaction system which used water immiscible hexane as the organic solvent. The role of a CD in the mono-phase reaction system was elucidated by comparing the degree of the inclusion complex formation with triolein and oleic acid, Km and Vmax values, and product inhibition by oleic aicd in aqueous and CD containing reaction systems. The resulting enhanced reaction seems to be caused by two phenomena; the increased accessibility of lipase to triolein and reduced product inhibition by oleic acid through the formation of an inclusion complex.