다양한 전처리 방법에 따른 양파의 이화학 및 영양학적 특성 분석

김광일 ( Kwang Il Kim ),황인국 ( In Guk Hwang ),유선미 ( Seon Mi Yu ),민상기 ( Sang Gi Min ),이상윤 ( Sang Yoon Lee ),최미정 ( Mi Jung Cho ) 한국산업식품공학회 2014 산업 식품공학 Vol.18 No.4

본 연구는 양파를 열처리 법 중에서 열수침지, 증기 및 볶음 처리에 따른 이화학적 및 영양학적 특성을 분석한 논문으로 열처리가 양파에 미치는 영향을 비교하고자 하였다. 상품을 구매할 때 1차적인 구매요소인 색도 및 경도측정과 추가적으로 pH와 조직관찰 결과로 최적조건 선정 후 영양학적 및 미생물 검사를 실시하였다. 열처리를 하지 않은 대조구에 비해 짧은 시간의 열처리에서는 더 진하고 선명한 색을 띠었으나, 장시간동안 처리한 열처리 시료는 색의 침착을 보였다. 원물과 처리구의 색은 열처리 시간에 따라 뚜렷한 차이를 나타냈고, 경도는 열처리 시간에 따라 짧은 시간에서는 분해효소의 불활성화로 유지 및 증가했지만, 3분 이상 처리하였을 때는 감소 경향을 나타냈고, 볶음처리는 짧은 시간으로도 물성이 연화됐다. 비타민은 열수 및 증기처리 1~2분 처리는 14% 정도 감소했지만 그 이상 처리 시에는 23~28% 범위로 큰 감소율을 보였으며, 유리당 및 유기산의 경우 열수침지 및 증기처리에서 손실을 보였지만, 볶음처리에서는 유지하거나 증가하는 경향을 나타냈다. 특히 유리당에서 열수침지 처리 시 높은 감소율을 나타냈다. Peroxidase activity 변화는 모든 처리구에서 75% 이상의 불활성화를 나타냈고, 특히 열수침지 및 증기 처리한 모든 시료에서 90% 이상의 불활성화를 나타내며 볶음처리보다 높은 불활성화율을 보였다. 미생물 측정한 결과 열수 침지 3분 이상 및 볶음처리 210초 이상 처리시 미생물 검출이 안됐으며, 증기처리 시료는 2분 처리만으로 사멸된 것을 관찰했다. 양파의 열처리 조건은 증기처리법으로 2분 동안 처리하는 것이 다른 처리법에서 처리한 시간들에 비해 최적으로 나타났다. 열처리 방법 별 각각의 최적 처리 시간을 가지고 있어, 높은 효율성이나 산업적으로 이용하려면 최적의 전처리 방법과 처리 시간을 산정하는 것이 중요하다. The pre-thermal treatment, or blanching, is an important process to minimize quality changes during main cooking or storage. In this study, three types of pre-thermal treatments were applied to onions to observe quality changes in their physicochemical, nutritional, and microbial properties. The washed and sliced onions were treated by hot-water immersion (100oC, 1~10 min), steaming (100oC, 1~10 min) and stir-frying with oil (180oC, 10~80 sec). The onions were cooled and wiped with gauze. The results showed that the total color difference of the treated sample increased to 18-23 units compared to that of the fresh control. The pH value of the onion was not significantly different with the exception of the stir-fried samples. The hardness of the onion tended to decrease depending on the treatment time. The micro-structures of onions treated by hot-water immersion and steaming were damaged above 2 min whereas stir-fried onions showed structural damage above 210 sec. In the analysis of the nutritional changes in the onion, the ascorbic acid content of the blanched treatments were lower than that of fresh onion and the free sugar contests showed a similar pattern excluding the stir-fried onions. In the organic acid content assay, the succinic acid content of the treated onion sample had significantly decreased compared with other organic acid contents (p<0.05). The peroxidase activities of the blanched treatments by hot-water immersion and steaming were inactivated by more than 92%, whereas only 76% inactivity was achieved by the stir-frying treatment. The mesophilic and psychrotrophic bacteria counts of the treated onion were not detected or decreased to near a 3-log scale, and yeast was detected only the sample treated by the stir-frying for 1 min. In particular, neither bacteria nor yeast counts in all onion samples by steam treatment were detected. Consequently, the results demonstrated that steam treatment for 2 min could be the optimal pre-thermal condition for onions to minimize the quality changes and increase safety.

대장직장 종양에 대한 내시경 점막하 절제술의 연대순 임상 결과와 학습 곡선

이상민 ( Sang Min Lee ),김은수 ( Eun Soo Kim ),박경식 ( Kyung Sik Park ),조광범 ( Kwang Bum Cho ),김동춘 ( Dong Choon Kim ),강유진 ( Yu Jin Kang ),이유진 ( Yoo Jin Lee ),이정민 ( Jung Min Lee ),최은성 ( Eun Sung Choi ),최재혁 ( Ja 대한소화기학회 2014 대한소화기학회지 Vol.64 No.4

Background/Aims: Endoscopic submucosal dissection (ESD) is an effective procedure for en-bloc curative resection of the colorectal tumor. As it requires high technical skills and experience in therapeutic endoscopy, it is important to understand learning curve of ESD technique. The aim of this study was to retrospectively describe the clinical results of ESD and to evaluate learning curve for the ESD of colorectal tumors. Methods: A total of 90 patients with 90 colorectal neoplasms, who had undergone ESD at a tertiary referral hospital from July 2009 to December 2012, were enrolled. The ESD was performed by a single endoscopist. All ESD cases were divided into three periods: first, cases 1-30; second, cases 31-60; and third, cases 61-90. Results: The en-bloc resection rates in third period (100%) was significantly higher than that of the first (93.3%) and second period (80%) (p=0.025). The perforation rate in third period (0%) also significantly decreased compared with that of the first (13.3%) and second period (20%) (p=0.032). To calibrate the difference of tumor size among periods, proficiency was calculated, as the procedure time per specimen area (min/cm2). The proficiency in third period (4.3) was significantly shorter than that of the first (16.8) and second period (10.2) (p=0.004). Conclusions: The learning curve of colorectal ESD in our study shows that at least 60 cases of ESD have to be conducted to acquire sufficient skill of degree without perforation. (Korean J Gastroenterol 2014;64:198-205)

경상남도 일부지역 농업인의 농약관련 인지도 및 실행도 결정요인

김정민,전만중,고광욱,유병철,이용환 고신대학교의과대학 2008 고신대학교 의과대학 학술지 Vol.23 No.2

Background : The amount of pesticide to be produced and consumed have rapidly growed in Korea and the evidences for pesticide intoxication to human body, natural environment and consumers have evoked. But the studies concerned to pesticide intoxication are inactive. So, we conducted this study about the determinants of awareness and performance for prevention of pesticide intoxication. Methods : The study conduced during the period from July to August 2007 with population consisted of 111 farmers. The toolkit was produced through referencing previous studies. Data analysis was performed with t-test, ANOVA and multiple linear regression analysis using SPSS 14.0K program. Results : The mean awareness score was 3.07 ± 0.75, the mean of total performance score was 2.72 ± 0.69, mean of subtotal performance score for keeping safety guideline was 2.72 ± 0.69 and mean of subtotal performance score for wearing protective equipments was 2.43 ± 0.83. Awareness score was associated with sex, age and family income. Female, older people and people with high income were tend to show low awareness score. Performance score was associated with sex, family income and educational level. Female, people with low education and high income were tend to show low performance score. Conclusion : We concluded that educational effort for noticing the harmful affects of pesticide, the importance of keeping safety guideline and wearing protective equipments to farmers especially female, older people, people with low education and high income were significant factors for prevention of pesticide intoxication.

치경부 5급 와동 수복물의 표면 거칠기와 미세누출에 관한 연구 : 표면 전색의 효과

김민정,이미정,유미경,박수정,이광원 大韓齒科保存學會 2005 Restorative Dentistry & Endodontics Vol.30 No.1

The purpose of this study was to compare the effect of surface sealing materials on microleakage and surface roughness in Class V composite restorations. Twenty five standardized Class V cavity preparations were made on the facial surface of human premolars and were randomly assigned to 5 groups. The teeth were restored with Z-250 after applying Single Bond. Following 7 days storage in distilled water at 37℃, the restorations were sealed as following systems : No sealing ; Single Bond Adhesive ; Biscover ; Fortify ; Optiguard. Then, toothbrush abrasion test was conducted using a wear testing machine. Surface roughness was measured by means of profilometer before and after toothbrushing and the results were statistically analysed by using a paired t-test and ANOVA. The bonded interfaces and the changes of surface roughness were examined by SEM. For microleakage test, specimens were stained in a 2% methylene blue solution, then longitudinally sectioned and analyzed for leakage at occlusal and cervical interfaces using stereomicroscope. The results were statistically analysed by using a Kruskal-Wallis and Mann-Whitney U test. Surface roughness was increasing in all groups after toothbrushing, but no statistically significant differences. In SEM observation, surface sealant was partially retained and partially detached in bonded interfaces. Especially, microgap was identified in cervical margins. In microleakage test, there was better seal in the enamel region and a significant difference between groups at occlusal margin. Control group and Single Bond group had significantly better marginal seal at enamel margin than cervical margin. 수복물의 변연 미세 누출과 마모 개선을 위해 표면 전색제가 개발되었으며 이의 효과에 대해 알아보기 위해, 규격화된 치경부 5급 와동을 25개의 소구치의 협면에 형성하고 Single Bond와 Z-250으로 수복한 뒤, 37℃의 증류수에 7일간 보관한 후 무작위로 5군으로 나누고 다음과 같은 재료로 제조사의 지시에 따라 표면 처리하였다 : No sealing ; Single Bond Adhesive ; Biscover ; Fortify ; Optiguard. 그 후 잇솔질 마모시험을 시행하였다. 표면 조도는 잇솔질 전후에 profilometer로 측정되었고 paired t-test와 ANOVA로 비교하였다. 접착면과 표면변화는 전자현미경으로 관찰하였다. 미세누출 평가를 위해 시편은 2% methylene blue 용액으로 염색한 뒤, 협설로 잘라 제작하였다. 입체현미경을 이용하여 교합면쪽과 치경부쪽 계면에서 미세누출을 관찰하고 Kruskal-Wallis와 Mann-Whitney U test를 이용하여 그 결과를 비교하였다. 표면 조도는 잇솔질 후 수치가 증가하였으나 통계학적으로 유의한 차이를 나타내지는 않았다. 전자 현미경 관찰 결과, 표면 전색제가 접착면에 부분적으로 남아있기도 하였으나 많은 부분에서 떨어져 나간 상태였다. 특히, 미세 틈새가 치경부쪽 변연에서 나타났다. 미세누출 실험에서는 법랑질에서 더 봉쇄효과가 좋았으며 교합면쪽 변연에서 군간에 유의할만한 차이를 나타내었다. 조절군과 Single Bond를 도포한 군에서는 치경부쪽 변연보다 법랑질쪽 변연에서 유의하게 좋은 변연 봉쇄 효과를 나타내었다.

성인학습원리 기반 웍샵에 의한 사회의학 교육평가의 시도

고광욱,김정민,김윤지,이용환,유병철,전만중 고신대학교의과대학 2007 고신대학교 의과대학 학술지 Vol.22 No.2

Background: For effective education of social medicine, new and more efficient means of education are needed because social medicine consist of diverse background academics . Metohods: Workshop based lecture was carried out twice in social medicine class for medical students and was assessed with questionnaires survey. Results: Half of the students were satisfied with workshop-based learning and required more discussion time and pre-information. Conclusions: With some improvements, workshop-based adult learning method is expected to bring effectiveness in social medicine education.

전기비저항을 이용한 금속합금 열화도 평가기술

남승훈,유광민,류제천 한국비파괴검사학회 2001 한국비파괴검사학회지 Vol.21 No.5

재료의 노화에 의한 강도 및 인성 감소치를 정량적으로 평가하는 비파괴적 기법의 개발이 시도되고 있으며 전기비저항법도 그 중의 하나이다. 본 연구에서는 전기비저항법의 열화도 평가에의 적용성을 살펴보기 위해 먼저 6종 10 가지의 비자성 금속을 측정시료로 선택하여 직류 two-point probe법(혹은 2탐침법)으로 전기비저항을 계산한 결과와 비접촉식 와전류 방법으로 전기비저항을 측정한 결과를 서로 비교하였다. 또한, 1Cr-1Mo-0.25V강에 대하여 비파괴적 측정 방법인 four-point probe 방법(혹은 4탐침법)을 사용하여 얻은 결과와 기존의 2탐침법을 사용하여 얻은 결과를 서로 비교하여 현장에서의 4탐침 기술의 적용 가능성을 살펴보았다. 1Cr-1Mo-0.25V강에 대하여 2탐침법으로 구한 비저항값과 4탐침법으로 구한 비저항 측정값의 차이는 0.6%였다. 따라서 4탐침법을 사용하여 현장에서 금속소재의 열화도의 비파괴적 평가가 가능하다고 사료된다. Developments of nondestructive evaluation techniques for reduction of strength or toughness by aging of material have been carried out, and the method using electrical resistivity is one of them. In this study, to examine the application of electrical resistivity to the evaluation of the evaluation of degradation of metallic alloy, ten different non-magnetic materials were selected as test materials. Electrical resistivities measured by DC two-point probe method and those measured by non-contact type eddy current method were compared with each other. In addition, to examine the application possibility of four-point probe technology in field, the electrical resistivities for 1Cr-1Mo-0.25V steel measured by DC two-point probe method and four-point probe method were compared with each other. Differences between two measure values for the 1Cr-1Mo-0.25V steel were0.6%. Therefore, the four-point probe method can be applied to the estimation of the degradation of metallic alloy.ect.

Research Articles : Quality Characteristics of Frozen Beef Developed into Home Meal Replacement Products Under Various Storage Conditions

( Sangyoon Lee ),( Kwang Il Kim ),( In Guk Hwang ),( Seon Mi Yu ),( Sang Gi Min ),( Mi Jung Choi ) 한국산업식품공학회 2015 산업 식품공학 Vol.19 No.3

Blanching and freezing of beef are important techniques used in developing frozen home meal replacement (HMR) products. These pre-thermal treatments minimize the deterioration of beef during storage. Beefs are washed, defatted, sliced (5.0×0.5×0.5 cm, fiber direction), and blanched by immersion in hot water for 2 min. Thereafter, the blanched beefs are spin-dried and frozen by individual quick freezing (IQF) method. Finally, the frozen beefs are packed using two methods: vacuum packages and air-containing packages. Packed beefs are stored at -12℃, -18℃, and -24℃ for nine months. One in every three months, they are thawed in a microwave (400W). While thawing, vacuum- packed samples possess lower thawing loss than air-containing-packed ones. Compared to raw beef, blanched beef have a higher L* and lower a* value. However, less changes are observed after blanching the beefs as the enzymes get inactivated in the blanching process. Shear force of beef also increase through blanching. Moreover, vacuum-packed samples have maintained their hardness to a greater extent than the air-containing-packed samples. All the samples have met microbial safety standards. Thus, it is inferred that vacuum-packaging and -18℃ storage temperatures are the best condition for maintaining beef that is later developed into HMR product.

AISI1045 기계구조용 탄소강의 질화 가스분위기에 따른 화합물층의 형성 및 조직변화

이원범 ( Won-beom Lee ),유광춘 ( Kwang-chun Yu ),김영민 ( Young-min Kim ),위재용 ( Jae-lyoung Wi ) 대한금속재료학회(구 대한금속학회) 2016 대한금속·재료학회지 Vol.54 No.7

Compound layers developed at 520 ℃ during gaseous nitriding of AISI 1045 steels were investigated. The nitriding potential (Kn) of a gas atmosphere of dissociating ammonia gas was checked by observation of the partial pressure of hydrogen gas. The microstructural evolution of the compound layer was studied by using optical microscopy and scanning electron microscopy. It was observed that the surface hardness was about 600 Hv after the nitriding treatment and the case depth was about 0.5mm after a nitriding treatment of 1440 min. The compound layer was composed of  ′(Fe4N) and ε(Fe2-3N). The thickness of the compound layer was simultaneously increased to 16 μm during the nitriding treatment of 1440 min. The kinetics of the compound layer growth were discussed with a modified Lehrer diagram of AISI 1045 steels, which was obtained from the thermodynamic calculation. †(Received January 15, 2016; Accepted March 2, 2016)

가역 투자율 측정에 의한 1Cr-1Mo-0.25V 강의 열화도 평가

유권상,김용일,남승훈,유광민,조육,손대락 한국비파괴검사학회 2000 한국비파괴검사학회지 Vol.20 No.5

고온에서 운용 중인 설비의 안전성을 평가하기 위해서는 사용기간동안 열화된 재료의 물성을 측정하여야 한다. 실제 사용되고 있는 화력발전소 터빈의 로터에서 열화도가 다른 여러 종류의 시편을 입수하기 어렵기 때문에, 터빈 로터재로 널리 사용되고 있는 1Cr-1Mo-0.25V 강을 인공열화시켜 시편으로 사용하였다. 열화도의 비파괴적 평가를 위하여 교류 섭동 자기장을 인가하여 가역 투자율을 측정하는 자기적 방법을 사용하였다. 열화도의 증가에 따라 경도와 가역 투자율 피크 사이의 간격은 감소하였는데, 경도와 가역 투자율 피크 간격과의 선형관계를 이용하여 비파괴적으로 터빈 로터강의 열화도를 평가할 수 있는 기초를 마련하였다. The integrity of the turbine totors can be assessed by measuring reversible permeability and Vickers hardness of the aged rotors at service temperature. The measurement system of reversible permeability, which measured by applied alternating perturbing magnetic field, was constructed in order to evaluate matrial degradation, nondestructively. The test specimen was 1Cr-1Mo-0.25V steel used widely for turbine rotor material, and the specimens were prepared by the isothermal heat treatment at 630 ℃. The reversible permeability of the test materials were measured at room temperature. The peak interval of reversible permeability and Vickers hardness decreased with the increase of degradation. The degradation of test material may be determined nondestructively by the lineality of Vickers hardness and the peak interval of reversible permeability.

Factors Influencing the Acrylamide Content of Fried Potato Products

Jin, Yong-Ik,Park, Kyeong-Hun,Chang, Dong-Chil,Cho, Ji-Hong,Cho, Kwang-Su,Im, Ju-Sung,Hong, Su-Young,Kim, Su-Jeong,Nam, Jung-Hwan,Sohn, Hwang-Bae,Yu, Hong-Seob,Chung, Ill-Min The Korean Society of Environmental Agriculture 2016 한국환경농학회지 Vol.35 No.4

BACKGROUND: Acrylamide (CAS No. 79-06-1) is known to be a carcinogenic compound, and is classified as a Group 2A compound by the International Agency for Research on Cancer (IARC, 1994). Acrylamide can be generated during the browning process via the non-enzymatic Maillard reaction of carbohydrates such as reducing sugars and of amino acids such as asparagine, both of which occur at a temperature above $120^{\circ}C$. Potato tubers contain reducing sugars, and thus, this will affect the safety of processed potato products such as potato chips and French fries. In order to reduce the level of acrylamide in potato processed products, it is therefore necessary to understand factors that affect the reducing sugar content of potatoes, such as environmental factors and potato storage conditions, as well as understanding factors affecting acrylamide formation during potato processing itself. METHODS AND RESULTS: Potatoes were cultivated in eight regions of Korea; For each of these different environments, soil physico-chemical characteristics such as pH, electrical conductivity, total nitrogen, available phosphate, and exchangeable cation content were measured and correlations with potato reducing sugar content and potato chip acrylamide levels were examined. The reducing sugar content in potato during storage for three months was determined and acrylamide level in potato chip was analyzed after processing. The storage temperature levels were $4^{\circ}C$, $8^{\circ}C$, or $10^{\circ}C$, respectively. The acrylamide content of chips prepared from potatoes stored at $10^{\circ}C$ or $20^{\circ}C$ for one month was analyzed and the different frying times were 2, 3, 5, and 7 min. CONCLUSION: This study showed that monitoring and controlling the phosphate content within a potato field should be sufficient to avoid producing brown or black potato chips. For potatoes stored at low temperatures, a reconditioning period ($20^{\circ}C$ for 20 days) is required in order to reduce the levels of reducing sugars in the potato and subsequently reduce the acrylamide and improve chip coloration and appearance.