• Corrosion Science and Technology
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• v.22 no.4
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• pp.242-251
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• 2023

The electrochemical corrosion behaviors of 304 stainless steels (STSs) with various coatings (organic coating and dry coating) were examined, and their applicability as bipolar plates in polymer electrolyte membrane fuel cells (PEMFCs) was validated. The results showed that the organic-coated samples had a significant decrease in anodic and cathodic current density compared to the uncoated sample. However, an increase in carbon black content in the organic coating or additional heat treatment at 700 ℃ resulted in a decrease in corrosion resistance. In addition, improvements in corrosion resistance achieved by adding TiO₂ powder to the organic coating were found to be limited. In contrast, dry coating with TiC and CrC exhibited higher corrosion potential, significantly lower current density, and reduced contact resistance compared to the organic coatings. Notably, the TiC-coated sample showed a comparatively lower current density and more stable behavior than the CrC-coated sample. Based on a series of experimental results, a thin TiC coating without defects is proposed as a promising surface treatment strategy for STS bipolar plates in PEMFC.

• The Korean Journal of Food And Nutrition
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• v.26 no.4
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• pp.985-989
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• 2013

This study was performed to determine the best conditions for preparing Toranbyung. We examined different boiling periods (0~20 min) and types of Gomyeong (pine nut, soy, black sesame, and chestnut powder), as recorded in "Sumunsasul". The boiled taros were evaluated for proximate composition, free sugar contents, and Hunter's color values. In addition, the sensory characteristics of Toranbyung boiled for different periods and prepared using different types of Gomyeong were investigated. The moisture, protein, fat, and ash contents of taro decreased by 83.42~84.61%, 1.25~1.31%, 0.08~0.11%, and 0.62~0.81%, respectively, as the length of boiling time increased. Fructose, glucose, and sucrose, the major free sugars found in taro, decreased by 0.17~0.33%, 0.16~0.29%, and 0.26~0.38%, respectively, as the length of boiling time increased. Sensory evaluation indicated no significant difference in the flavor and taste of Toranbyung boiled for different periods of time. However, Toranbyung boiled for 10 min was significantly better and was found to be the most acceptable among all the samples. Furthermore, sensory evaluation of Toranbyung prepared with different types of Gomyeong indicated that the Toranbyung prepared with soy powder was favored over Toranbyung prepared using other types of Gomyeong. In conclusion, we determine that the best conditions for preparing Toranbyung were boiling for 10 min and using soy powder as the Gomyeong.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.3
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• pp.179-187
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• 2010

This study examined ways to improve the functional properties of commercial soy sauce using gelatin hydrolysates from the refiner discharge of Alaska pollock, Theragra chalcogramma. The total nitrogen content and pH of gelatin sauce prepared by dissolving the second-step gelatin hydrolysates (15 g), salt (20 g), sugar (5 g), glucose (2.5 g), inosine monophosphate (IMP) (0.5 g), black pepper (0.1 g), caramel powder (0.1 g), ginger powder (0.05 g), garlic powder (0.05 g), vinegar (3 mL), and fructose (3 mL) in water(100 mL) were 1.71% and 5.35, respectively. The results of a sensory evaluation indicated that when preparing blended soy sauce, the optimal blending ratio of gelatin sauce to commercial soy sauce was 20:80 (v/v). Because the total nitrogen content and pH of the blended soy sauce were 1.52% and 5.31, respectively, the blended soy sauce could be sold as a soy sauce. The oxidative property of the blended soy sauce was similar to that of 20 mM ascorbic acid, and its angiotensin-converting enzyme (ACE) -inhibiting activity was 1.5 mg/mL. The results suggest that the antioxidative and ACE-inhibiting activities of commercial soy sauce can be improved by blending gelatin sauce (20) with commercial soy sauce (80). The total amino acid content of the blended soy sauce was 9,107.3 mg/mL, which was higher than that (8,992.4 mg/100 mL) of commercial soy sauce. However, the taste value of the blended soy sauce was 415.8, which was lower than that (431.2) of commercial soy sauce.

• Journal of Life Science
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• v.25 no.1
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• pp.68-74
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• 2015

Recently developed black waxy rice with a giant embryo ('Nunkeunheukchal', BGE) was selected and processed to produce high quality nutritional food. BGE contains high levels of several phytochemicals with antioxidant activities, as well as other reported health beneficial properties. In addition, the giant embryo has high protein, lipid, and amino acids contents. Within the free amino acids, ${\gamma}$-aminobutyric acid (GABA), a major inhibitory neurotransmitter, has long been used for treating the aftereffects of brain injuries and stroke. A method for manufacturing pop-rice and black rice tea by popping process in BGE is provided to increase a taste, nutrition and functionality. The produced 'pop-rice' showed increased protein (11.3%) and lipid (3.7%) contents compared with control variety, IB ('Ilmibyeo'). In addition, melanoidin related products, polyphenol and functional amino acid contents were increased by the popping process. Pop-rice tea made of BGE showed the highest extraction of total sugar, glucose, raffinose and sucrose (4 times higher than brown rice) by hot water. Scavenging activity ($SC_{50}$) of processed BGE rice powder showed strong antioxidative activity of 0.24 mg/ml using DPPH and 1.82 mg/ml using ABTs method. Thereafter, these results suggested that the popping processed rice of BGE could be one of the promising materials for healthy food development.

• Korean Journal of Food Science and Technology
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• v.35 no.1
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• pp.125-131
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• 2003

Physiological activities of hot water extracts of 10 commercial instant curry powders and 6 spices, were investigated. All spice extracts except ginger showed significant antioxidant activities on the autoxidation of linoleic curry acid (p＜0.01). Antioxidant activities of clove and fennel were significantly higher than ${\alpha}-tocopherol$, instant curry powders, and other spices, Red pepper $(52.8{\pm}2.13%)$, clove, and coriander showed significant inhibitory activities against angiotensin-I-converting enzyme (p＜0.001). Cytotoxic effects of instant curry powder and spices against human cancer cell lines were examined through MTT assay. Black pepper $(29.31{\pm}2.21%\;cytotoxic\;rate)$ and cardamon $(19.41{\pm}3.92%)$ were effective against MCF-7 (p＜0.01), Clove $(42.92{\pm}5.57%)$ against HeLa (p＜0.01). Ginger $(34.21{\pm}1.11%)$, cardamon, and black pepper against A172 (p＜0.001), garlic $(82.88{\pm}0.53%)$ against SN12C (p＜0.001), garlic $(71.63{\pm}0.38%)$, red pepper, ginger, fenugreek, SPC, cumin, and MPC against SNU-638 (p＜0.001), and cassia $(82.84{\pm}16.92%)$ against A549 (p＜0.001).

• Korean Journal of Food Science and Technology
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• v.48 no.5
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• pp.399-404
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• 2016

The applicability of photostimulated-luminescence (PSL) and thermoluminescence (TL) for the detection of 12 food materials (potato, onion, garlic, dried pumpkin, black mushroom, black soybean, Cheongkukjang powder, sea mustard, pepper powder, Ramyun soup, corn tea, and green tea powder) irradiated with an electron beam, gamma ray, and X ray at a range of 0.15 to 10 kGy was investigated. For PSL, negative results (less than 700 photon counts (PCs)) were observed from non-irradiated foods while the irradiated foods showed intermediate (879 to 2,414 PCs) and/or positive (19,951 to 65,919,035 PCs) values. In all irradiated samples, the maximum peak of the TL glow curve was observed between 150 and $250^{\circ}C$. Our findings demonstrate the successful application of PSL and TL to determine whether food items were irradiated or not. However, there were no significant differences among the radiation sources.

• Food Science and Preservation
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• v.22 no.2
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• pp.281-289
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• 2015

This study was conducted to examine the effects of a supplemented Chungkukjang diet on oxidative stress and antioxidant nutrients in Streptozotocin (STZ, 45 mg/kg of BW, IP injection)-induced diabetic rats. Diets that contained soybean Chungkukjang powder (SC), Yakkong Chungkukjang powder (YC), and Yakkong Chungkukjang powder with black food added (YCB) were administered to the STZ-induced diabetic rats for seven weeks. The increased lipid peroxide contents of their serum and liver were slightly controlled by providing them three types of Chungkukjang. The retinol level in the serum was 7.5 times higher in the STZ-induced diabetic group after the provision of YC. The total antioxidant capacity (TAC) level in the serum was higher in the STZ-induced diabetic group after the provision of YCB. Also, the retinol and tocopherol levels in the liver of the STZ-induced diabetic rats increased after they were provided YCB, and the decreased reduced glutathione (GSH) /oxidized glutathione (GSSG) level in their liver improved after they were fed a diet that contained YC. Moreover, the decreased anthocyanin level in the liver of the STZ-induced diabetic group improved after the provision of three types of Chungkukjang powder. These findings suggest that the Chungkukjang diet is a valuable food for the management of the health of diabetic patients and for the prevention of diabetic complications.

• Korean Journal of Food Science and Technology
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• v.48 no.2
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• pp.133-141
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• 2016

The physicochemical properties, antioxidant capacities, and sensory optimization of taro (Colocasia esculenta) under different aging conditions were investigated to develop black taro. Black taro was processed in three steps (steaming: $95{\pm}3^{\circ}C$ for 1 h; aging: 85, 90, $95^{\circ}C$ for 20, 40, and 60 h; drying: $60^{\circ}C$ for 24 h) and ground into a powder for all experiments. Black taro showed an increased crude fiber content and browning index compared to raw taro. Calcium oxalate contents, reducing sugar contents, moisture contents, and lightness values were decreased during the processing of taro. Improvements in total polyphenol content and antioxidant activity (DPPH, ABTS, FRAP) were observed in the black taro samples aged at higher temperature. Response surface methodology was used for sensory optimization, and the optimum aging conditions with the highest acceptance values were found to be $88.73^{\circ}C$ for 39.50 h for taste, and $88.82^{\circ}C$ for 42.60 h for overall acceptance.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.7
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• pp.1011-1020
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• 2003

The present study was conducted to examine sensory characteristics of non-fermented tea and fermented teas with fermented times of 0 hr (green tea), 10 hrs (mild fermented tea), 17 hrs (medium fermented tea), 24 hrs (black tea), respectively. The lightness of tea powder and tea extract got lower, and the redness and the yellowness of those got higher as tea was more fermented. The result of sensory evaluation about the extracts of non fermented tea and fermented teas showed that the preference of flavor got higher in the more fermented tea but one got lower in a mild fermented tea according to temperatures, respectively. The preference of taste got higher at 60∼7$0^{\circ}C$ extracts in the green tea and got the highest at 80∼9$0^{\circ}C$ extracts in the medium fermented tea and black tea. A total of 76 flavor components was detected in non fermented tea and the total contents of those were 129.9 mg/kg. The major components were linalool, geraniol, nerolidol, benzyl alcohol, and linalool oxide. A total of 76 flavor components was detected in the mild fermented tea and total contents of those were 159.1 mg/kg. The major components were geraniol, linalool, linalool oxide, ethanol, benzyl alcohol, etc and were similar in those to the non fermented tea. A total of 79 flavor components was detected in the medium fermented tea and total contents of those were 455.6mg/kg. The major components were ethyl acetate, 3-methylbutanal, ethanol, (E)-2-hexenal, geraniol, linalooloxide. A total of 79 flavor components was detected in the Black tea and total contents of those were 680.5 mg/kg. The major components were 3-methylbutanal, ethyl acetate, geraniol, ethanol, (E)-2-hexenal, hexanal, linalooloxide. The amounts of flavor components was increased, but the amounts of aldehyde compounds was remarkably increased according to the degree of fermentation.

• Korean Chemical Engineering Research
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• v.44 no.3
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• pp.307-313
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• 2006

In order to improve the efficiency of methane steam reforming process, a part of the system which produces hydrogen from heavy hydrocarbon resources such as coal, we combined metal catalyst with CaO sorbent and fabricated catalyst/sorbent. To increase the porosity and the compressive strength of sorbent, carbon black and ${\alpha}-alumina$ were mixed with CaO powder during preparation. The effects of sorbent composition on the physical properties were investigated by SEM, TGA, BET, XRD, abrasion strength measuring device and adsorption-desorption instrument. Sorbent with 5 wt％ $Al_2O_3$ and 10 wt％ carbon black showed the best physical features with $7.61kg_f$ strength and 47％ $CO_2$ adsorption capability. Various metal catalysts such as Ni, Co and Fe were supported on the sorbent developed and 10 wt％ Ni/sorbent was selected for methane steam reforming process based on the result of reaction experiment. The reaction system using the catalyst/sorbent showed better $H_2$ productivity compared to the detached system with catalyst and sorbent, indicating the effectiveness of the system developed in this study.