마이크웨이브 추출조건에 따른 참취 추출물의 총 폴리페놀 함량 및 항산화작용의 변화

김현구,권영주,김영언,남궁배 한국식품저장유통학회 ( 구 한국농산물저장유통학회 ) 2004 한국식품저장유통학회지 Vol.11 No.1

마이크로웨이브 추출방법과 환류 냉각 추출방법을 비교한 결과, 물과 에탄올의 혼합용매로 추출한 경우 마이크로웨이브 추출 방법에 의하여 추출시간을 단축시키면서 환류 냉각 추출 방법에서와 같은 수준의 가용성 고형분 및 총 폴리페놀 함량을 갖는 참취 추출물을 얻을 수 있었다. 마이크로웨이브 추출시 최적 마이크로웨이브 에너지는 120∼150 W 였고 추출시간은 4∼8분이 적당하였다. 추출에 사용한 용매들 가운데 에탄올, 메탄올 보다 물 그리고 물과 에탄올 또는 메탄올 혼합용매를 사용한 추출물의 가용성 고형분, 총 폴리페놀 함량 및 항산화 효과가 높은 것으로 나타났다. This study was conducted in order to compare reflux extraction(RE) and microwave-assisted extraction(MAE) in extraction efficiency and establish optimum microwave extraction condition in obtaining Aster scaber Thunb extracts. Extraction time was reduced considerably in MAD. When 70% methanol, 50% methanol, 70% ethanol, or 50% ethanol was used, no difference was found in the amount of soluble solid and total phenol between MAE and RE. The optimum microwave-assisted extraction conditions for Aster scaber Thunb were achieved by 120~150 watts of microwave energy and 4~8 minutes of extraction time. No signigicant changes were found in antioxidant activity using DPPH scavenging method over the variation of microwave power or extraction time. The use of diluted methanol or ethanol improved soluble solid content(30.8%), total polyphenol content(2.9%) and antioxidant activity(69%).

오미자 추출물의 추출특성 및 항산화 효과

김현구,나경민,예수향,한호석 한국식생활문화학회 2004 韓國食生活文化學會誌 Vol.19 No.5

The present study was conducted to investigate extraction characteristics and antioxidative activity of Schiznadra chinensis extracts. Schiznadra chinensis was extracted by reflux extraction(RE) under different extraction conditions including solvent. The solid yield, turbidity, color value, titratable acidity, free sugar contents, electron donating ability(EDA) and superoxide dismutase(SOD)-like ability of Schiznadra chinensis extracts were determined. The highest solid yield value was obtained with water of 10 fold. No significant difference in turbidity and color value were found among the extracts prepared with various extraction solvents, 75% ethanol, 50% ethanol and water. The highest titratable acidity was obtained with water extracts of Schiznadra chinensis. The free sugar contents of Schiznadra chinensis extracted with water showed the highest value. Schiznadra chinensis extracts with water included higher contents of free sugar compared with those of the other solvent extracts, 50% ethanol and 75% ethanol extracts. The total polyphenol compound content of Schiznadra chinensis extracted with 50% ethanol showed the highest value. Schiznadra chinensis extracts with 50% ethanol included higher contents of total polyphenol compound compared with those of the other solvent extracts, water and 75% ethanol extracts. The electron donating ability of extracts were 60.87% in water, 57.24% in 50% ethanol, and 55.61% in 75% ethanol.

중앙행정기관 주요정책과제평가의 분석적 논고

김현구 한국정책학회 2003 韓國政策學會報 Vol.12 No.4

「평가기본법」에 의한 정부업무평가 중 전형적인 기관평가 모형을 취하고 있는 것이 중앙행정기관평가이고, 중앙행정기관평가의 근간을 이루는 것이 주요정책과제평가이다. 이 글은 국무총리 정책평가위원회가 주관하는 주요정책과제평가의 제도적 운영을 분석하고 개선방안을 모색하는 데 그 목적이 있다. 이를 위해 먼저 평가기관의 역량과 대상기관의 호응을 제도적으로 살펴본 다음, 주요정책과제평가의 추진과정을 평가준비, 평가실행, 결과처리의 3단계로 나누어 논의하였다. 평가준비 단계는 과제선정, 평가성검토, 평가계획의 순으로, 평가실행 단계는 평가운영, 평가기준, 평정방법을 중심으로, 결과처리 단계는 분석·정리, 보고·조치, 이행점검의 순으로 검토하였다. 주요정책과제평가의 실효성 제고를 위해서는 무엇보다 평가기관의 전문성 및 지원체계 강화, 기관별 우열 공표, 대상과제 수의 대폭 축소, 평가성검토의 강화, 평가기준의 다원화, 평가내용의 체계적 분석, 평가결과와 예산의 연계 등이 주요 개선과제라고 할 수 있다. The Major Policy Evaluation(MPE) is an annual assessment of the process of representative policies for 43 central agencies by the Policy Evaluation Committee (PEC) and the Office for Government Policy Coordination(OGPC) of the Prime Minister's Office in Korea. This article examines the MPE system dividing its procedure into three stages. The preparation stage focuses on the procedure of major policy selection, evaluability assessment, and evaluation plan. The execution stage analyzes operation, criteria, and methods of evaluation. The treatment stage deals with analysis, report and action, and monitoring. This study also sheds some light on the capacity of evaluator(PEC, OGPC) and cooperation of evaluated agencies from institutional aspects. For the improvement of MPE system, the author suggests various measures including enhancement of evaluator's expertise and supporting system, opening of evaluation grade by agency, reduction of evaiuated policies, intensification of evaluability assessment. diversification of evaluation criteria, and consideration of evaluation results in budget allocation.

아황산처리 및 건조온도가 건조마늘 플레이크의 품질에 미치는 영향

신효선,김현구 동국대학교 1987 論文集 Vol.26 No.-

The browning color development during drying of sliced garlic flakes was greatly dependent on drying temperature and moisture content, and the reciprocal proportion between the formation rate of browning color and the reduction rate of reducing sugar was found. The browning color development during drying of the flakes was effectively impeded with sulfiting concentration of 0.1%, 0.5%, and 1.0% at drying temperature of 65℃, 75℃ and 85℃, respectively. The reduction of pyruvate during drying of the flakes was greatly influenced by drying temperature and sulfiting concentration, and the remarkable reduction of it has been analyzed when above 85℃ of drying temperature and above 1.0% of sulfiting concentration. Sulfiting treatment showed antimicrobial activity which diminished bacterial flora from 5.7×10^5 for control to 9.9×10^4 after treatment of 1.0% sulfiting solution in dehydrated products of sliced garlic flakes.

Pseudomonas sp. CB-33이 생산하는 β-Xylosidase의 특성

유진환,김현구,김치경,임재윤 한국미생물생명공학회 ( 구 한국산업미생물학회 ) 1996 한국미생물·생명공학회지 Vol.24 No.2

Pseudomonas sp. CB-33 균주의 배양 상등액으로부터 ammonium sulfate 침전법, PEI 침전법, DEAE-Sephadex column chromatography, gel column chromatography 그리고 preparative disc gel electrophoresis를 이용하여 β-xylosidase를 정제하였다. 정제된 효소의 Km 값은 4.6 mM이었다. 효소활성의 최적 pH는 7.0이었으며 pH 6.5~9 범위에서 안정하였다. 최적 활성온도는 45℃였으며, 각 온도에서 30분 동안 정치하였을 때 35℃까지 안정하였다. SDS-PAGE에 의해 효소의 분자량을 측정해 본 결과 약 44,000dalton이었다. HG^2+, Cu^2+ 그리고 Zn^2+는 효소활성을 저해하였고, 여러 화학변형제로 효소에 처리해 본 결과 tyrosine과 tryptophan이 효소활성에 관여하고 있을 것으로 추정된다. 여러가지 기질에 대한 특이성을 조사해 본 결과 pNPX 뿐만 아니라 pNPA도 분해하였다. Xylan에 endoxylanase만을 작용시켰을 때보다 β-xylosidase와 endoxylanase를 혼합작용 시켰을 때 xylan의 가수분해도는 약 2배 정도 증가하였다. 그리고 Pseudomonas sp. CB-33 균주가 생산하는 xylan 분해효소는 oat spelt xylan보다 birchwood xylan에 보다 효과적으로 작용하였다. The β-xylosidase was purified 99-fold from the culture supernatant of Pseudomonas sp. CB-33 by ammonium sulfate precipitation, PEI precipitation, DEAE-Sephadex column chromatography, Sephadex G-75 gel filtration chromatography and preparative disc gel electrophoresis. Molecular weight of the enzyme was estimated to be 44,000 by SDS polyacrylamide gel electrophoresis. The enzyme has a pH optimum for activity at 7.0 and is stable over pH 6.5~9.0. The optimal temperature of the enzyme was 45℃, and it enzymatic activity was completely inactivated at 55℃ for 30 min. Km value of the enzyme for p-nitrophenyl- β-D-xylopyranoside was calculated to be 4.6 mM. The effect of various reagents on the β-xylosidase activity was investigated. The enzyme activity was completely inhibited by Hg^2+, Cu^2+, and Zn^2+. The β-xylosidase was inactivated by tryptophan-specific reagent, N-bromosuccinimide and the enzyme was competitively inhibited by xylose. The β-xylosidase and endoxylanase from Pseudomonas sp. CB-33 hydrolized xylan synergically. The purified enzyme also showed α-L-arabinofuranosidase activity.

감마선 조사가 조미오징어의 저장 중 품질특성에 미치는 영향

노정은,김병근,김현구,권중호 한국식생활문화학회 2004 韓國食生活文化學會誌 Vol.19 No.5

This study was conducted to investigate the changes in the quality of gamma-irradiated seasoned cuttle during storage. Seasoned cuttle packed in PVC film (0.06 mm) was stored at 15±1℃ for 6 months after treatment with doses of 0 to 7 kGy. Microbial populations of seasoned cuttle were 1.6×10^5 CFU/g in total aerobic bacteria, 10⁴~10^5 CFU/g in yeasts & molds, and negative in coliforms, which were effectively reduced by 3 kGy or higher up to the undetectable level(〈20 CFU/g). The pH and moisture content of the samples were not changed with irradiation, but moisture was some decreased during storage. The instrumental color (especially Hunter b value), pigments (lipophilic & hydrophilic) and TBA value of the samples increased with storage time as well as irradiation dose more than 3 kGy. The influence of storage condition, however, were more significant. Irradiation did not induce any changes in volatile basic nitrogen (VBN) and trimethylamine (TMA) contents, thereby maintaining their contents lower than those of the non-irradiated samples during storage by reducing the microbial load.

결명자 추출물의 추출특성 및 항산화 효과

나경민,한호석,예수향,김현구 한국식생활문화학회 2004 韓國食生活文化學會誌 Vol.19 No.5

The present study was conducted to investigate extraction characteristics and antioxidative activity of Cassia tora L. extracts, Casia tora L. was extracted by reflux extraction under different extraction conditions including solvent. The solid yield, turbidity, color value, titratable acidity, free sugar contents, electron donating ability and superoxide dismutase-like ability of Cassia tora L. extracts were determined. The highest solid yield value was obtained with water of 10 fold. No significant difference in turbidity and color value were found among the extracts prepared with various extraction solvents, 75% ethanol, 50% ethanol and water. The highest titratable acidity was obtained with 50% ethanol of Cassia tora L.. The free sugar contents of Cassia tora L. extracted with water showed the highest value. Cassia tora L. extracts with water included higher contents of free sugar compared with those of the other solvent extracts, 50% ethanol and 75% ethanol extracts. The total polyphenol compound content of Cassia tora L. extracted with 50% ethanol showed the highest value. Cassia tora L. extracts with 50% ethanol included higher contents of total polyphenol compound compared with those of the other solvent extracts, water and 75% ethanol extracts.