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Daejeon, South Korea

Lee D.-W.,Kyungnam University | You D.-H.,Kyungnam University | Yang E.-K.,Kyungnam University | Jang I.-C.,Kyungnam University | And 4 more authors.
Journal of the Korean Society of Food Science and Nutrition | Year: 2010

The antioxidant and angiotensin converting enzyme (ACE) inhibitory harvesting times were evaluated. During February and July of 2008, Styela clava were harvested once per month, and divided into flesh and tunic parts. Each collected part was extracted with water and 70% ethanol. DPPH radical scavenging activity (RSA) for flesh part was higher than that of tunic part, and water extract of flesh harvested at April showed the highest value (53.02% at 10 mg/mL). The highest ABTS RSA was found at water extract of flesh part harvested atMarch. Water extracts of flesh parts harvested from March to May showed relatively higher ACE inhibitory activity, and freezing did not affect ACE inhibitory activity. The results indicated that antioxidant and ACE inhibitory activity of S. clava were variable depending on harvesting time and parts. Source


Jo J.-E.,Chungnam National University | Yook H.-S.,Chungnam National University | Kim K.-H.,Chungnam National University | Baek J.-Y.,Chungnam National University | And 3 more authors.
Journal of the Korean Society of Food Science and Nutrition | Year: 2010

This study was carried out to examine the changes of the quality feature and antioxidant activity of grape by-products. This experiment was to arrange the basic data for developing a functional material using grape by-products which were useless resources. Hot-air and freeze drying were followed by the gamma irradiation of 1~20 kGy. Hunter's color value, in case of hot-air drying, showed the highest L and a value in the 3 kGy, and it decreased according to the increase of the exposure dose. In the case of freeze drying it showed the highest L and b value at the highest exposure, 20 kGy. It was considered that the breakdown of the pigment through high temperature processing was launched and the influence according to the gamma irradiation was not shown. The gamma irradiation of 3 kGy appeared to have a good influence on the color of the grape by-products which went through hot-air drying. The contents of the total phenolic compounds, in case of hot-air drying, showed the highest total polyphenol contents in the 3 kGy irradiation and it decreased according to the increase of the exposure dose; in contrast, the higher phenolic contents showed in the irradiated group than in the control. In case of freeze drying, the highest phenolic contents appeared in the control but 3 kGy showed the highest one in the irradiated group. Results of radical scavenging activity using DPPH and ABTS indicated that 3 kGy showed the highest radical scavenging activity in hot-air and freeze drying. Therefore, it was found that gamma irradiation of 3 kGy could improve the color and antioxidant activity of grape by-products, but an antioxidant activity of grape by-product due to the gamma irradiation was a little affected in the aspects of by-product utilization. Source


Kim J.,Kyungnam University | Lee J.-H.,Andong National University | Kim S.-J.,Woosong Information College | Jeon Y.-J.,Jeju National University | Park E.,Kyungnam University
Journal of the Korean Society of Food Science and Nutrition | Year: 2011

Styela plicata of large (9.82~11.66 g) and small (0.93~2.21 g) sizes harvested at different times was extracted with 4 different solvents (methanol, ethanol, acetone, and water). DPPH radical scavenging and reducing power was the highest in acetone extracts of small ones (38.98% and 1.724, respectively) harvested in November. The lowest radical scavenging activity was found in water extracts of large ones (12.03% and 0.114) in December. On the other hand, large ones harvested in September showed significantly higher inhibition rate of DNA damage (water, 56.54%; methanol, 55.83%; ethanol, 48.63%) than others. Overall, the water extraction of S. plicata tended to show a higher antigenotoxic effect. In addition, water extracts of large S. plicata from November showed the highest angiotensin converting enzyme (ACE) inhibitory activity (64.38%), while that of small ones from December exhibited the lowest (51.33%). Overall the results indicate that antioxidant and antihypertensive activities S. plicata are variable depending on harvesting time, size, and extraction solvent. Source


Cho C.-G.,Chosun University | Lee B.Y.,Chonnam National University | Kim Y.Y.,Chungnam National University | Han B.-C.,Woosong Information College | Lee S.-J.,Chosun University
Advances in Materials Science and Engineering | Year: 2012

This paper presents a new reinforced concrete (RC) composite slab system by applying an extruded Ductile Fiber Reinforced Cement Composite (DFRCC) panel. In the proposed composite slab system, the DFRCC panel, which has ribs to allow for complete composite action, is manufactured by extrusion process; then, the longitudinal and transverse reinforcements, both at the bottom and the top, are placed, and finally the topping concrete is placed. In order to investigate the flexural behavior of the proposed composite slab system, a series of bending tests was performed. From the test results, it was found that the extruded DFRCC panel has good deformation-hardening behavior under flexural loading conditions and that the developed composite slab system, applied with an extruded DFRCC panel, exhibits higher flexural performance compared to conventional RC slab system in terms of the stiffness, load-bearing capacity, ductility, and cracking control. Copyright © 2012 Chang-Geun Cho et al. Source


Lee B.Y.,Chonnam National University | Han B.-C.,Woosong Information College | Cho C.-G.,Chosun University | Kim Y.Y.,Chungnam National University
Computers and Concrete | Year: 2012

This paper presents the mix composition and production method that was applied to an extruded Ductile Fiber Reinforced Cement Composite (DFRCC) panel, as well as the flexural performance, represented by deformation hardening behavior with multiple cracking. The effect of fiber distribution characteristics on the flexural behavior of the panel is also addressed. In order to demonstrate the fiber distribution effect, a series of experiments and analyses, including a sectional image analysis and micromechanical analysis, was performed. From the experimental and analysis results, it was found that the flexural behavior of the panel was highly affected by a slight variation in the mix composition. In terms of the average fiber orientation, the fiber distribution was found to be similar to that derived under the assumption of a two-dimensional random distribution, irrespective of the mix composition. In contrast, the probability density function for the fiber orientation was measured to vary depending on the mix composition. Copyright © 2012 Techno Press. Source

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