• Korean Journal of Food Science and Technology
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• v.26 no.4
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• pp.365-369
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• 1994

In attempt to explain the effect of heat processing on the product quality in manufacturing strawberry jam, the heat stability of anthocyanin in strawberry by addition of some sweetners was studied, and the effect of sucrose by concentration and pH were also investigated. The heat stability of anthocyanin was maximum at pH 2.5 when maintaining at $87^{\circ}C$ for 60 minutes initially, but it was shifted to pH 3.0 after additional heating of 120 minutes. When the corn syrup, sucrose and glucose were used as a sweetner for manufacturing strawberry jam, the results showed that heat stability of anthocyanin in corn syrup was higher than that in sucrose and fructose, and the optimum concentration of sucrose for heat stability was 66 Brix%. The results also showed that anthocyanin content in strawberry jam significantly decreased logarithmically at $37^{\circ}C$, and spreadmeter value changed slightly at $37^{\circ}C$storage but it was not significant.

• Tribology and Lubricants
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• v.2 no.2
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• pp.59-64
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• 1986

쌍용정유는 윤활기유 생산을 위한 최신공정인 Gulf 특허의 수질첨가 개질공정을 채택, 일본, 카나다에 이에 세계에서 3번째로 건설된 공장으로서 국내 수요전량을 수입에만 의존해 오던 재래식 공정인 용제유출 방식의 윤활기유를 대신하여, 최고급 품질의 윤활기유를 국내에 안정적으로 공급할 수 있는 확고한 기반을 마련하고 지난 5년여 동안 국내수요에 적극 공급해오고 있다. 일반적으로 볼때 쌍용정유에서 생산.공급하고 있는 윤활기유는 국내 각 정유사등 윤활유배합(제조)회사에 공급되어 용제에 따라 첨가제를 배합하는등, 소포장 단계를 거쳐 일반수요자에게 판매되는데, 완제품 윤활유의 사용은 대략 65% 정도가 자동차에 쓰여지고 있으며 공장등 산업시설에 23%, 선박, 기타 용도로 12%정도의 사용분포를 보이고 있다. 산화, 열안정성은 기유의 생명 불순물제거 완벽, 색상 뛰어나 수질첨가 개질공정은 재래식 공정인 용제추출 방식과 어떤 차이점을 갖고, 제품의 특성이 어떤 차이를 나타내는가를 알아보기 위해서는 2가지 방식에 의한 제품의 장단점을 비교해보는 것이 바람직하다고 하겠다.

• Microbiology and Biotechnology Letters
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• v.13 no.4
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• pp.349-354
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• 1985

A 4.7 kb Hind III fragment containing $\alpha$-amylase gene of Bacillus stearothermophilus IAM 11062 was cloned in Escherichia coil HB101, using plasmid pBR322 and runaway plasmid pSY343 as a vector. The cloned gene was stably maintained and expressed In E.coli. The constructed strain of E. coli have at least 3 times higher amylase activity than the donor strain, of B. stearothermophilus. About 75％ of the $\alpha$-amylase produced by the constructed strain of E. coli was localized in the periplasm and it was found that the enzymes can be released by an osmotic shock using EDTA. The enzymatic properties of L-amylase produced in E. coli were very similar to those produced by B. stearothermophilus in terms of optimum temperature, heat stability and molecular weight.

• Korean Journal of Food Science and Technology
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• v.28 no.4
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• pp.743-749
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• 1996

This study was carried out to investigate the microencapsulatuion of ${\omega}-3$ fatty acid isolated from fish oil and to obtain fundamental information on the utilization of the ${\omega}-3$ fatty acid in the dairy foods field. To obtain the desirable microencapsulation efficiency, 1.5% agar and 0.5% gelatin were used as coating materials, and 0.5% SFAN 60 (HLB 4.5 value) was used to maintain the emulsion stability. The optimal mixing ratio of coating material to core material was 8:2 (w/w). The thermostability of microencapsulated product was not maintained above $60^{\circ}C$. Microencapsulation efficiency was kept at about 90% at $4^{\circ}C$ and $10^{\circ}C$ for 7 days storage at various temperatures. At $20^{\circ}C$ and $30^{\circ}C$, however, about 80% microencapsulatuion efficiency was obtained for 3 days storage. About 80.57% microcapsule was destroyed by 1%> pepsin solution at $37^{\circ}C$ for 10 min.

• Journal of the Korean Society of Food Science and Nutrition
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• v.13 no.4
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• pp.397-402
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• 1984

As a basic research for inhibition of enzymatic browning of apple wine, polyphenol oxidase (EC 1.10.3.1) from apple (Jonathan) was extracted, partially purified, and some properties of the enzyme and changes o( active bands by heat treatment were investigated. Optimum conditions for the enzyme reaction were pH6.5 and temperature of $30^{\circ}C$, and o-diphenol was the main substrate for the enzyme. Approximately 35% and 15% of initia lpolyphenol oxidase activity remained after heating at $60^{\circ}C$ and $70^{\circ}C$ for 1 hour, respectively. About 0.5mM of the inhibitor such as sodium metabisulfite, cysteine and ascorbic acid was required for effective inhibition of the enzyme reaction. However, EDTA was found to be a very poor inhibitor. Ethanol did not affect the enzyme activity. The number of active bands of polyphenol oxidase from apple(Jonathan) was found to be four, but two bands and one band were observed after heating at $60^{\circ}C$ and $70^{\circ}C$ for 1 hour, respectively, which showed a significant difference in thermal stability among active bands.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.11a
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• pp.29-29
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• 2011

폴리에스테르는 많은 분야에서 응용되어 사용되어지고 있으나 최근 더욱 우수한 물성이 각 분야에서 요구되어 지고 있다. Poly (ethylene naphthalate)(PEN)는 PET 주쇄의 벤젠고리에 나프탈렌으로 치환되어 강직성이 강화되어 PET보다 약 $50^{\circ}C$정도 높은 $T_g(117^{\circ}C)$와 $10^{\circ}C$정도 높은 $T_m(265^{\circ}C)$을 가져서 열적 안정성, 고강도와 저신도를 갖는다. PEN은 상대적으로 우수한 내열성과 환경호르몬을 포함하지 않아 인체에 무해하다는 이점 때문에 수유병이나 머그컵으로도 사용되어질 수 있다. 또한 탄산음료 용 bottle이나 맥주 bottle등은 높은 barrier성이 요구되어지기 때문에 PET에 비해 약 5배 높은 barrier 성을 가지는 PEN을 블렌드하여 사용하기도 한다. PEN의 내열성 및 기계적 강도를 더욱 우수하게 하고자 고분자 사슬을 가교할 수 있는데, 가교에는 열처리 또는 감마선, 전자선, 자외선 조사를 이용할 수 있는데 열에 의한 가교는 균일한 열전달과 고온이 필요하며 감마선 및 전자선 조사는 설비의 고비용과 방사선 노출 위험으로 인해 비친환경적이다. 반면에 자외선 조사법은 다루기 쉽고 비용이 적게 들고 친환경적인 장점을 가진다. 본 연구에서는 PEN film의 열안정성과 기계적 특성을 향상시키기 위해 자외선 조사를 이용하여 PEN film의 광가교를 수행하였다.

• Korean Journal of Materials Research
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• v.6 no.10
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• pp.1034-1042
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• 1996

본 연구에서는 인산코팅된 것과 되지 않은 OXI-PAN섬유를 사용하여 제조된 무질서 배향의 OXI-PAN/페놀수지 복합재료를 불활성분위기의 여러 열처리온도에서 탄화하였을 때, 섬유표면에 인화합물의 존재 유.무가 복합재료의 물리적특성 및 미세구조 변화에 미치는 영향을 조사하였다. 두 종류 복합재료의 물리적특성 변화를 탄화온도 영향에 대한 섬유와 매트릭스 및 그 계면에서의 미세구조 거동변화와 기공형성의 관점에서 해석하였다. 열처리시 온도상승에 따라 섬유와 매트릭스 계면에서의 화학반응에 의해서 그 구분이 점차 사라지면서 국부적으로 치밀하고 균일한 상을 이루고 있는 것으로 조사되었다. 또한, 탄화 조건에서도 인산코팅은 OXI-PAN 섬유의 직경의 감소를 억제하고 열안정성을 향상시키므로 복합재료의 부피수축률을 줄이고 탄화수율을 증가시키는데도 어느정도 기여할 수 있으리라 판단되었다.

• Korean Journal of Food Science and Technology
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• v.43 no.2
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• pp.176-181
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• 2011

Cronobacter sakazakii and Salmonella enterica Typhimurium are hazardous pathogens, especially for ready-toeat foods. For control of pathogens, the virulent bacteriophages were isolated, identified, and applied to infant formula milk and vegetable juice. The phages were isolated from swine feces and identified by morphology and molecular characteristics. ES2 phage for C. sakazakii and ST2 phage for S enterica Typhimurium were identified as Myoviridae and Siphoviridae, respectively. Their burst sizes were $52{\pm}5PFU/cell$ for ES2 phage and $21{\pm}3PFU/cell$ for ST2 phage after latent period of 30-40 minutes. ST2 phage showed higher heat stability at $60^{\circ}C$ than ES2 phage. ES2 phage held the growth of C. sakazakii untill 6 hr afterwhich the number decreased when applied to the infant formula milk and vegetable juice. ST2 phage also showed growth inhibition so that the number of S. enterica Typhimurium decreased. Therefore, virulent bacteriophages might be an agent for the growth inhibition of C. sakazakii and S. enterica Typhimurium in such the ready-to-eat foods.

• Journal of Life Science
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• v.23 no.1
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• pp.15-23
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• 2013

AprE51 from Bacillus amyloliquefaciens CH51 is a 27 kDa subtilisin-like protease with fibrinolytic activity. AprE51-6 showing increased catalytic activity was produced previously. To enhance the thermostability of AprE51-6, 2 residues, Gly-166 and Asn-218 based on B. subtilis subtilisin E were mutated by site-directed mutagenesis. The results of the mutational analysis showed that substitution of arginine for Gly-166 (AprE51-7) increased the fibrinolytic activity 1.8-fold. An N218S mutant (AprE51-8) also increased the fibrinolytic activity up to 4.5-fold in a fibrin plate assay. Purified AprE51-7 and AprE51-8 mutants had a 1.9- and a 2.5-fold higher $k_{cat}$, respectively, and a 2.1-1.9-fold lower $K_m$, respectively. This resulted in a 3.8- and a 4.7-fold increase in catalytic efficiency ($k_{cat}/K_m$), respectively, relative to that of wild-type AprE51. AprE51-8 had a broader pH range than AprE51-6 and nattokinase, especially at an alkaline pH value. In addition, AprE51-8 showed higher thermostability than AprE51-6 at $60^{\circ}C$. The half-lives of AprE51-7 and AprE51-8 at $50^{\circ}C$ were 21.5 and 27.3 min, respectively, which are 2.0 and 2.6 times longer, respectively, than that of the wild-type AprE51.

• Microbiology and Biotechnology Letters
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• v.30 no.4
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• pp.293-297
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• 2002

The cyclodextrin glucanotransferase (CGTase) gene from Bacillus stearothermophilus NO2 was expressed in Saccharomyces cerevisiae 2805 under the adhl promoter. The CGTase was purified from S. cerevisiae 2805/pVT-CGTS. The purified enzyme exhibited a optima of activity around pH 7.0 and $65^{\circ}C$. Thermal stability of the enzyme was increased fairly as compared with the CGTase of B. stearothermophilus NO2. The conversion yield of cyclodextrin (CD) and the production ratio of $\alpha$-, $\beta$,-, ${\gamma}$-CD from starch were showed similarly aspect to the CGTase of B. stearothermophilus NO2.