High-temperature oxidation of a Ni-based superalloy was analyzed with samples taken from gas turbine blades, where the samples were heat-treated and thermally exposed. The effect of Cr/Ti/Al elements in the alloy on high temperature oxidation was investigated using an optical microscope, SEM/EDS, and TEM. A high-Cr/high-Ti oxide layer was formed on the blade surface under the heat-treated state considered to be the initial stage of high-temperature oxidation. In addition, a PFZ (γ’ precipitate free zone) accompanied by Cr carbide of Cr23C6 and high Cr-Co phase as a kind of TCP precipitation was formed under the surface layer. Pits of several μm depth containing high-Al content oxide was observed at the boundary between the oxide layer and PFZ. However, high temperature oxidation formed on the thermally exposed blade surface consisted of the following steps: ① Ti-oxide formation in the center of the oxide layer, ② Cr-oxide formation surrounding the inner oxide layer, and ③ Al-oxide formation in the pits directly under the Cr oxide layer. It is estimated that the Cr content of Ni-based superalloys improves the oxidation resistance of the alloy by forming dense oxide layer, but produced the σ or μ phase of TCP precipitation with the high-Cr component resulting in material brittleness.

본 연구는 복합추출물(익모초, 어성초, 진피)의 생리활성을 측정하여 식·의약품, 화장품 등의 소재로서의 가능성을 확인하고자 하였다. 복합추출물은 열수 추출하였으며, 세포독성, 항산화, 항염증, MAPKs 등의 평가는 ELISA 및 western blot을 통해 확인하였다. 그 결과, 총 폴리페놀 함량은 35.53±0.48 ㎎ GAE/g, 플라보노이드 함량은 8.18±0.16 ㎎ QE/g으로 나타났으며, DPPH 와 ABTS radical 소거능은 농도 의존적으로 증가하였다. 대조군과 비교하여 세포독성은 400 ㎍/㎖ 농도까지 100% 이상의 생존율이 나타났으며, NO 및 염증성 사이토카인을 유의하게 감소시켰다. 또한, 복합추출 물은 MAPKs(ERK, JNK, p38) 단백질 발현을 유의하게 억제시켰다. 이러한 결과는 복합추출물이 산화 적 손상 및 염증에 사용될 수 있음을 나타낸다. 따라서 본 연구 결과는 식·의약품, 화장품용 복합소재의 의 기초자료로 활용될 수 있을 것이다.

To increase antioxidant and antibacterial activities of seasoned soy sauce, five kinds of oriental medicinal plant(Scutellaria baicalensis (P1), Coptis japonica makino (P2), Citriunshius pericarpium (P3), Zizyphi spinosi semen (P4), Crataegus pinnatifida (P5)) and four kinds of medicinal mushrooms(Inonotus obliquus (M1), Hericium erinaceus (M2), Phellinus linteus (M3), Lentinula edodes (M4)) were added to seasoned soy sauce. Soluble solid content, pH, salinity, total polyphenol & flavonoid contents were determined. DPPH & ABTS radical scavenging activities, SOD-like activity, and antibacterial activity were analyzed. Experimental sauces showed decreased pH but significant increases of soluble solid content and salinity. Total polyphenol content was 12.76 μg GAE/g in the control. However, M1 and P1 sauce had significantly higher polyphenol contents at 352.14 and 528.25 μg GAE/g, respectively. Total flavonoids content also showed the same pattern. DPPH free radical scavenging activity was the lowest in the control at 15.75%. It was the highest at 81.80% in M1 and 68.88% in P1. ABTS free radical scavenging activity and SOD-like activity showed the same tendencies. They were higher in the experimental groups than in the control. As for the antibacterial activity analyzed by the paper-disc method, the activity increased the most in P1 and P2. In particular, P2 had the strongest antibacterial activity. Its activity against different microorganisms was in the order of Staphylococcus aureus > Bacillus cereus > Escherichia coli > Salmonella typhimurium. In conclusion, these new sauces show increased antioxidative and antioxidant activities. Therefore, they are expected to be used in various ways as a functional soy sauce.

Makgeolli’s fermentation characteristics and antioxidant and antimicrobial activities were investigated to examine the effect of Prunus mume extract addition. Makgeolli, with the addition of various levels (0, 1, 3, and 5%) of Prunus mume extract (PME), was brewed with fermenting agents, Ipguk and Nuruk. The alcohol content of all samples remarkably increased during the initial 3 days and then gradually increased up to over 18% by the end of fermentation (7 days for Nuruk and 15 days for Ipguk). Although the alcohol content was slightly reduced and acidity was increased with the concentration of PME, there was no other negative effect of PME on the fermentation of Makgeolli. The contents of total phenols and flavonoids for Ipguk samples were higher than those for Nuruk samples, and these values significantly increased at over 3% PME addition. As the PME content increased, the antioxidant activity increased for both Nuruk and Ipguk samples. Only Makgeolli with Ipguk had vigorous antimicrobial activity against E. coli and S. aureus at over 3% addition of PME. These results indicate that PME can be an effective natural additive for enhancing Makgeolli’s antioxidant and antimicrobial activities.

To increase antioxidant activity and physicochemical quality characteristics, four kinds of berries (blueberry (BEB), blackberry (BKB), cranberry (CNB), raspberry (RSB)) with antioxidant activities were used to replace beet (B) in existing ABC juice. In the experimental group, the pH was decreased while the content of soluble solids was increased significantly. Total polyphenol content was significantly increased in all experimental groups compared to that in the control group. The control group had the lowest polyphenol content at 14.723 μg GAE/g, whereas the blackberry replacement group had the highest polyphenol content at 67.12 μg GAE/g. The total flavonoid content was the lowest in the control group at 8.98 μg QE/g but the highest in the blackberry group at 50.47 μg QE/g. All experimental groups showed significantly higher antioxidant activities than the control group. DPPH & ABTS radical scavenging activities were the lowest in the control group at 15.69% and 19.55%, respectively, but the highest in the blackberry group at 48.24% and 59.43%, respectively. SOD-like activity was also the lowest in the control group at 14.12%, but the highest in the blackberry group at 48.18%. When comparing experimental groups, antioxidant activities (DPPH, ABTS, SOD) and antioxidant components (total polyphenols and total flavonoids) were in the order of BKB > CNB > RSB > BEB > Control. In conclusion, the new ABC juice containing four types of berries is enriched in antioxidants with significantly improved antioxidant activities and physicochemical quality characteristics.

In this study, scones were prepared using Cordyceps powder, described as ‘immortal life’. Cordyceps powder was prepared in 0%, 2%, 4%, 6%, and 8% ratios, and salinity, color, texture, and antioxidant properties were analyzed. The salinity of Cordyceps scones did not show a difference according to the amount of Cordyceps powder added (p=0.364), and the a-, b-values increased significantly (p<0.001). In the case of texture, there was no significant difference in the amount of Cordyceps added. Flavonoids increased significantly as the amount of Cordyceps powder increased (p<0.001). ABTS-radical scavenging capacity increased significantly as the amount of Cordyceps powder increased (p<0.001). Through this study, the antioxidant properties of Cordyceps scones were confirmed.

The study investigated the potential effect of the Ecklonia cava extract by using Jeju lava seawater (ECE-JLS; hardness: 100, 300 mg/L), which is naturally filtered underground by a volcanic rock layer. The chemical composition, antioxidant-related enzyme activities, radical scavenging activities, reactive oxygen species (ROS) production in Vero cells, and nitric oxide (NO) production in Raw 264.7 cells were measured to evaluate the antioxidant and anti-inflammatory activities of the extract. The total polyphenol and flavonoid contents of ECE-JLS100 and 300 were 156.41± 1.15, 166.16±2.27 mg/g, and 343.76±2.40, 373.90±3.67 mg/g, respectively. The concentration of ECE-JLS’ SOD and CAT-like activities was increased. ECE-JLS in the range of 0.25 to 2 mg/mL exhibited remarkable DPPH radical and hydrogen peroxide scavenging activities. ECE-JLS100 and 300 inhibited total ROS generation by 21.4±0.4 and 23.9± 0.3% in H2O2-induced Vero cells at 200 g/mL concentration, respectively. ECE-JLS100 and 300 decreased NO production, with levels of about 55.0±2.4 and 56.5±1.8% at 200 g/mL concentration, respectively. The contents of TNF-  were decreased compared to the negative control. These observations provide helpful information for the potential industrial use of Jeju lava seawater. Also, ECE-JLSW could be used as a functional food material.

생물환경조절학회지 31권 4호에 게재된 논문의 사사가 잘못 기재되어 있어 바로 잡습니다.

개똥쑥(Artemisia annua L.)은 국화과 (Compositae)에 속하는 일년생 초본으로 예로부터 진 통, 안면마비 등의 신경계 질환과 위염, 호흡기 등의 질병치료 목적으로 이용되는 식물로 알려져 있다. 개똥쑥을 열수 및 70% 에탄올로 추출하여 추출용매에 따른 추출물의 농도별로 항산화 활성 및 항염증 효과에 미치는 영향을 검토하고자 실시하였다. 총 polyphenol의 함량은 개똥쑥 70% 에탄올 추출물에서 열수 추출물에 비하여 유의적으로 높게 나타났으나, 총 flavonoid 함량은 개똥쑥 열수 추출물과 70% 에 탄올 추출물에서 유의적 차이는 보이지 않았다. DPPH radical 소거능력과 ABTS radical 소거능력은은 62.5∼500 μg/mL 농도에서는 비타민 C 처리구에서 가장 높게 나타났고 그 다음으로는 70% 에탄올 추출물, 열수 추출물 순으로 높게 나타났다. 125 ∼ 500 μg/mL에서 NO 생성 억제효과를 측정한 결 과 열수 추출물에서는 500 μg/mL 농도에서 강한 NO 생성 억제를 보이며, 농도의존적으로 NO 생성 억제를 나타났다. 70% 에탄올 추출물에서는 NO 생성 억제 뿐 아니라 염증성 싸이토카인 발현을 현저 히 억제하는 결과를 보이며, 농도의존적인 억제 효과를 나타났다. 개똥쑥은 항산화효과 및 염증성 싸이 토카인의 발현을 현저히 감소시키는 효과를 보이므로 염증성 질환 치료 및 개선에 널리 사용될 수 있으 리라 사료된다.

This study aimed to investigate the physicochemical characteristics and antioxidant activity of cereal bars containing various concentrations (0, 10, 20, or 30%) of apple pomace (AP). Highest vitamin B1 and C contents were observed in 30% AP-containing bars, but vitamin B2 and B3 contents were highest in the control (0.347 and 3.566 mg/100 g, respectively). Cutting strength decreased significantly in an AP concentration-dependent manner. Total polyphenol and flavonoid contents in 10% AP bars were 2.949±0.157 mg of GAE/g and 1.001±0.009 mg of CE/g, respectively. Antioxidant activities were assessed by measuring free radical scavenging activities, and 10% AP bars had the highest activities, as determined by ABTS (2,2'azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) and DPPH (α-α-diphenyl-β-picrylhydrazyl) assays (0.412±0.008 and 0.492±0.021 mg GAE/g, respectively). These results suggested that apple pomace should be regarded a potential nutritional and antioxidant source.

The Cheonggukjang used in this study was made with four soybean cultivars grown and harvested at the National Agrobiodiversity Center of the National Academy of Agricultural Sciences: C1 (KLS87248), C2 (Nongrim 51), C3 (GNU- 2007-14613), and C4 (Daewon). The soybeans were inoculated with Bacillus subtilis AFY-2 and fermented for 0, 12, 21, 36, 45, and 60 h in a culture room at 35°C. ABTS and DPPH radical scavenging activities were significantly increased upon fermentation for 12 hours in all samples and maintained or decreased after 21 hour The inhibition of NO production was significantly increased compared to the LPS-treated group, and the C2 sample showed inhibition of NO production at 12 hours of fermentation, and the C3 sample showed inhibition at 21 hours of fermentation. PCA analysis revealed that the ABTS and DPPH radical scavenging activity and NO production inhibitory activity reached peak levels around 12 h fermentation time for all samples. Our results indicate that the optimal fermentation time of the Cheonggukjang sample is 12 hours, confirming the high correlation of all experiments.

This study investigated the quality characteristics and antioxidant effects of rice cookies containing different percentage of freeze-dried plum powder (3%, 5%, 6%, and 12%). The density of the dough and the thickness of the rice cookies from the control group and the additive group were not significantly different. The pH value of the dough, its moisture content and spread factor, as well as the Hunter’s L and b values of the rice cookies significantly decreased as the amount of dried plum powder added increased. However, the sweetness, hardness, thickness, Hunter’s a value, total polyphenol, total flavonoid and anthocyanin contents, DPPH and ABTS free radials scavenging activity, and ferric reducing antioxidant power of the rice cookies significantly increased as the amount of dried plum powder added increased. Overall, the results of this study showed that adding dried plum power enhanced the antioxidant activities and quality characteristics of rice cookies.

This study compared the antioxidant and mineral properties of the leaves and seeds of fifteen Korean adzuki bean (Vigna angularis L.) breeding lines. This study was conducted in an attempt to expand the use of Korean adzuki bean leaves. The potassium, calcium, magnesium, and sodium contents of the leaves were significantly higher than the seeds, in particularly, the potassium content. The leaves had approximately 3.3 times higher potassium content than the seeds. For instance, the potassium content of YA1317 leaves was 21% higher than that of Arari. The total polyphenol content and ABTS activity of Adzuki bean leaves were significantly higher than the seeds, as opposed to the total flavonoid content and DPPH scavenging activity. Among the 15 breeding lines, YA1402 had 1.2~3.2 times higher antioxidant content and activity as compared to the Arari variety. It was concluded that adzuki bean leaves had higher mineral content, antioxidant component and activity as compared to the seeds. Therefore, adzuki bean leaves could be used an ingredient for dishes and as a medicine.

Thermal protection systems (TPS) are a group of materials that are indispensable for protecting spacecraft from the aerodynamic heating occurring during entry into an atmosphere. Among candidate materials for TPS, ceramic insulation materials are usually considered for reusable TPS. In this study, ceramic insulation materials, such as alumina enhanced thermal barrier (AETB), are fabricated via typical ceramic processing from ceramic fiber and additives. Mixtures of silica and alumina fibers are used as raw materials, with the addition of B4C to bind fibers together. Reaction-cured glass is also added on top of AETB to induce water-proof functionality or high emissivity. Some issues, such as the elimination of clumps in the AETB, and processing difficulties in the production of reusable surface insulation are reported as well.

Yttria-stabilized zirconia (YSZ) has a low thermal conductivity, high thermal expansion coefficient, and excellent mechanical properties; thus, it is used as a thermal barrier coating material for gas turbines. However, during long-time exposure of YSZ to temperatures of 1200oC or higher, a phase transformation accompanied by a volume change occurs, causing the YSZ coating layer to peel off. To solve this problem, YSZ has been doped with trivalent and tetravalent oxides to obtain coating materials with low thermal conductivity and suppressed phase transformation of zirconia. In this study, YSZ is doped with trivalent oxides, Nd2O3, Yb2O3, Al2O3, and tetravalent oxide, TiO2, and the thermal conductivity of the obtained materials is analyzed according to the composition; furthermore, the relative density change, microstructure change, and m-phase formation behavior are analyzed during long-time heat treatment at high temperatures.

This study aimed to investigate the biological activities, including polyphenolic content, flavonoid content, and antioxidant activities, of various cultivars of Korean perilla leaves. The results indicated that among nine cultivars (Namcheon dlggae, Saedora, Nulbora, Donggel 1, Donggell 2, Soim, Sangyeop, Somirang, and Saebom) of perilla leaves, the total polyphenolic content (gallic acid equivalent mg/g, GAE) was the highest in “Nulbora,” while it was lowest in Namcheon dlggae. Moreover, flavonoid content in the extracts of nine cultivars leaves was in the range of 132.93~268.50 mg catechin equivalent/g sample. The antioxidant effects of the perilla leaves were determined using two different in vitro bioassays measuring DPPH and ABTS radical-scavenging activities. The results revealed that antioxidant activity was also higher in “Nulbora” compared with other cultivars. Xanthin-oxidase-inhibition activity ranged from 65.65% to 80.58%, with “Nulbora” exhibiting the highest activity, although the difference with other cultivars was not significant. “Nulbora” extracts reduced the expression of pro-inflammatory genes and several cytokines, including IL-6 activation induced by LPS in macrophages in the range of 100–50 μg/mL. These results suggest that extracts from perilla leaves can be used as bioactive and functional materials that could be important in industrial applications in the future.

The quality and antioxidant characteristics of apios (Apios americana Medikus) according to different harvest periods and steaming treatment were investigated. The quality and antioxidant characteristics of apios were significantly different depending on harvest periods. Total starch contents was higher in 1st harvesting period as 62.32 g/100 g than other harvesting period. The water binding capacity and water solubility index was higher in 1st harvesting period as 228.65 and 11.29% than other harvesting period. The sucrose and total free sugar contents were 3.64~8.67 and 4.49~9.54 g/100 g, respectively. Total polyphenol and flavonoid contents of apios was the highest 2nd and 4th harvesting period at 4.21 mg GAE/g and 611.11 μg CE/g, respectively. DPPH radical scavenging activity was higher in 1st harvesting period as 84.96 mg TE/100 g than other harvesting period, and decreased as the harvest periods were delayed. ABTS radical scavenging activity and ferric-reducing antioxidant power were 43.81~47.89 mg TE/g and 231.20~264.07 mM/100 g, and increased to 50.58~51.44 mg TE/g and 342.55~384.29 mM/100 g after heat treatment. As a result, it is thought that studies on change of quality and physicochemical characteristics according to cultivation characteristics should be preceded for cultivation stability of apios.

The purpose of this study was to investigate the antioxidant activities, quality characteristics, and storage stability of perilla oil mayonnaise (PM) with different levels of onion powder (OP) from 0 to 3%. As the amount of OP increased, the L, a, and b values increased, but pH decreased (p<0.05). The addition of OP raised viscosity (p<0.05). The addition of OP to PM proportionally increased the total phenolic content, and antioxidant activities as measured by DPPH and ABTS radical scavenging activity, and FRAP assay. When compared to PM without OP, PM that contained OP had a peroxide value that was almost 1.94 times lower. The emulsion stability was between 97.62 to 94.92% in the PM without OP and PM with OP groups was 99.60% for 12 weeks. This study showed that the inclusion of OP in PM has the potential to inprove its quality, antioxidant activities, and storage stability.