• Korean Chemical Engineering Research
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• v.55 no.3
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• pp.385-394
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• 2017

In this study, reaction mechanism and curing characteristics of adhesives formulated with NaOH- and $H_2SO_4$-hydrolyzed chicken feather (CF) and formaldehyde-based crosslinkers were investigated by FT-IR and DSC. In addition, adhesive properties and formaldehyde emission of medium-density fiberboards (MDF) applied with the adhesives were measured. CF-based adhesives having a solid content of 40% and over were very viscous at $25^{\circ}C$, but the viscosity reduced to $300{\sim}660m{\cdot}Pa{\cdot}s$ at $50^{\circ}C$. Consequently, the adhesives could be used as a sprayable resin. Through the FT-IR spectra of liquid and cured CF-based adhesives, addition reaction of methylol group and condensation reaction between the functional groups with the use of formaldehyde-based crosslinkers were identified. From the analysis of DSC, it was elucidated for CF-based adhesives to require a higher pressing temperature or longer pressing time comparing to commercial urea-formaldehyde (C-UF) resin. MDF bonded with CF-based adhesives, which was formulated with 5% NaOH-hydrolyzed CF (CF-AK-5%) and PF of formaldehyde to phenol mole ratio of 2.5 (PF-2.5), and pressed for 8 min had higher MOR and IB than those with other CF-based adhesives. MOR and IB of MDF bonded with the CF-based adhesives regardless of formulation type and pressing time were higher than those with C-UF resin. When the values compared with the minimum requirements of KS standard, IB exceeded the KS standard in all formulations and pressing time, but MOR of only MDF bonded with CF-AK-5% and PF-2.5 and pressed for 8 min satisfied the KS standard. What was worse, 24-TS of MDF bonded with all CF-based adhesives did not satisfied the KS standard. However, MOR and 24-TS can be improved by increasing the target density of MDF or the amount of wax emulsion, which is added to improve the water resistance of MDF. Importantly, the use of CF-based adhesives decreased greatly the formaldehyde emission. Based on the results, we reached the conclusion that CF-based adhesives formulated under proper conditions had a potential as a sprayable resin for the production of wood panels.

• Korean Journal of Food Science and Technology
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• v.35 no.6
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• pp.1098-1103
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• 2003

Soybeans released proteins when immersed in water at $50{\sim}60^{\sim}C$. We investigated the changes in the characteristics of soybean when soaked in water at different temperatures and studied the electrophoretic properties of soy proteins in recommended Korean soybean varieties after heat treatment. Soybean seeds were heated in soaking water at temperatures of 30, 40, 50, 60, $70^{\circ}C$ for 90 min, and also from 10 to 150min at $60^{\circ}C$. The pH value of the water decreased with heating time at $60^{\circ}C$, and the amount of soluble solids increased with temperature and heating time. The protein concentration of the solution increased with temperature and time. From SDS-PAGE of the proteins in soaking water, we detected two new bands of 16 kDa- and 31 kDa-proteins from the Korean soybean varieties on heat treatment.

• Food Science and Preservation
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• v.15 no.3
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• pp.477-482
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• 2008

The quality characteristics of Goami by-product under the mixed enzyme treatment condition of $\alpha$-amylase and cellulase have been compared, and found the highest amount of soluble solids and reducing sugars at the $\alpha$-amylase treated group (A), and the contents revealed to show gradual decrease with the increase of cellulase content. The amounts of total dietary fiber and total sugars did not show large difference by both of enzyme concentration. The result of sugar analysis revealed the presence of all $G{\sim}G5$ in all treatment groups, and the content of malto-oligosaccharide recorded the highest content of 2,200 mg% at the $\alpha$-amylase treatment group (A). When the quality characteristic of the hydrolyzed powders manufactured by the optimum hydrolysis condition was compared, no significant color difference was found between samples. Among the contents of dietary fibers, insoluble dietary fiber was found to present in the lowest content of 6.95% at the Goami flour (GF) and the Goami by-product powder (GBPP) and Goami by-product hydrolysate powder (GBPHP) resulted the similar content around 14% and the highest soluble dietary fibers content was found in Goami by-product hydrolysate powder (GBPHP), which was followed by in the order of Goami by-product powder (GBPP) and Goami flour (GF), but the content variation was not large. The free amino acid was found to be highest in Goami by-product hydrolysate powder (GBPHP) followed by in the order of Goami by-product powder (GBPP) and Goami flour (GF). In the sugar analysis, the Goami by-product hydrolysate powder (GBPHP) was found with all $G{\sim}G5$ sugars by showing the highest amount of 1,800 mg% At the Goami by-product powder (GBPP), $G{\sim}G2$ sugars were detected with about 66 mg% and malto-oligosaccharides were not detected at the Goami flour (GF). Based upon the results, the functionality of Goami by-product hydrolysate powder (GBPHP) was found to be enforced compared to Goami flour (GF) and Goami by-product powder (GBPP), which allow us to expect it to be used as the various rice processing food source.

• Food Science and Preservation
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• v.21 no.6
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• pp.790-798
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• 2014

The nutritional compositions and antioxidative activities of the Kimcheon lowbush and Pyungtaek highbush blueberries cultivated in South Korea were investigated. The approximate compositions, pH, and soluble-solid and mineral contents of P, Ca, Mg, Na, and Zn were determined. Both blueberry cultivars had mainly fructose and glucose as free sugars while disaccharides such as sucrose, maltose, and lactose were not detected in both. Oleic, linoleic, and linolenic fatty acids were the major fatty acids in both types of blueberries. The total of 16 free amino acids, including seven essential and nine non-essential amino acids, were higher in the Pyungtaek highbush blueberry. Among the amino acids, arginine was especially much higher in the Pyungtaek highbush blueberry. The anthocyanin, resveratrol, and polyphenol compounds, which are the important biologically active compounds in blueberries, were found. The anthocyanin contents of the Kimcheon lowbush and Pyungtaek highbush blueberries were 22.0 and 18.1 mg/100 g, respectively; the resveratrol contents by HPLC, 0.12 and 0.11 mg/100 g; and the total polyphenol contents, 141.3 and 138.4 mg/100 g. The electron-donating ability determined based on the DPPH radical scavenging activity was increased in a concentration-dependent manner, and it was higher than that of the Pyungtaek highbush blueberries, which implies that it is highly correlated with the higher amounts of total polyphenol, anthocyanin, and resveratrol in it. In conclusion, the two varieties of Korean blueberries can be suggested as potential sources of high-value-added functional foods.

• Journal of the Korea Organic Resources Recycling Association
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• v.20 no.2
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• pp.66-75
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• 2012

The objective of this study was to assess the effects of methanogenic bacteria-activated leachate recirculation method for enhancing waste stabilization and landfill gas production from a solid waste landfill. To simulate a conventional landfill (Lys-A), a landfill recirculated only fresh leachate (Lys-B), and two landfills recirculated leachate after pretreating with ASBR (Lys-C and Lys-D), four lysimeters were operated over a period of 4 years. Lys-D was recirculated two times of pretreated leachate volume than that of Lys-C. In the case of the landfill recirculated only fresh leachate and the landfill recirculated leachate after pretreating with ASBR, methane productions were increased until about 600 days, but there were not effect of leachate recirculation for enhancing methane production after about 600 days. It was assumed that leachate recirculation into fewer biodegradable organic wastes had not effect to enhance landfill gas production. Lys-C and Lys-D showed the highest performance for enhancing cumulative methane yield as well as acceleration waste stabilization. In cumulative methane yield, Lys-C (35.51 mL $CH_4/g$ VS) and Lys-D (36.12 mL $CH_4/g$ VS) were much higher than Lys-A (28.37 mL $CH_4/g$ VS) and Lys-B (30.07 mL $CH_4/g$ VS). In case of between Lys-B and Lys-C with the same recirculation rate, COD concentration in Lys-C was more rapidly decreased compared with that in Lys-B. This was attributed to the presence of methanogenic bacteria as well as dilution of inhibitory substances by the methanogenic bacteria-activated leachate recirculation. Therefore, the landfill recirculated leachate after pretreating with ASBR was found to be the most appropriate operating techniques for enhancing waste stabilization and landfill gas production.

• Food Science and Preservation
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• v.24 no.2
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• pp.254-265
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• 2017

For the production of ${\gamma}-aminobutyric$ acid (GABA) contents increased Seomaeyaksuk fermentant, 0, 0.25, 0.5 and 1.0% of monosodium galutamate (MSG) was added in Seomaeyaksuk water extract 15% contained Sikhye and inoculated with Lactobacillus brevis (KI271266). Physicochemical properties were sampling and analyzed at each 1 day during 3 days fermentation. Goes on fermentation periods, the turbidity was gradually reduced, but lightness and the yellowness was increased, redness was decreased. Soluble solid was also decreased. The reducing sugars content were also decreased during fermentation. pH was 4.65-4.83 before fermentation but it was lower 3.15-3.68 after three days fermentation. The GABA contents increased by fermentation periods and it was the highest in MSG 1.0% added sample (354.38 mg/L). Fructose, glucose and sucrose contents were 50-67% decreased at three days fermentation than before fermentation. Among the organic acids, propionic acid, oxalic acid, citric acid and fumaric acid contents were decreased and lactic acid, acetic acid and succinic acid were increased during fermentation periods. Contents of total polyphenol and DPPH radical scavenging activity were the highest in MSG 0.5% added sample. From these results, we confirmed that increasing of GABA content when the manufacturing of Seomaeyaksuk lactic acid fermentation product, is possibile by addition of MSG without affecting physicochemical characteristics.

• Journal of Animal Environmental Science
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• v.2 no.1
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• pp.41-52
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• 1996

This experiment was carried out to study the effect of sprinkler and fan cooling system on the physiological parameter, milk production and milk composition for Holstein cows in hot, humid climates. Thirty cows were assigned to one of two sections of open-sided loose barn. Water nozzles of sprinkler system were spaced in line at 1.2m intervals. Forced air was provided by 85cm diameter fans at rate of 3.4㎥/sec. The results obtained from these experiments are as follows: 1. There was no significant difference in meteorological data between control and fan + sprinkler cooling system(treatment group). 2. Skin temperature and rectal temperature of the treatment group were significantly lower than those of the control group (32.96 : 39.53$^{\circ}C$ vs 34.02 : 41.21$^{\circ}C$ respectively) (P<0.05). 3. Serum cortisol concentration of the treatment group(0.90$\mu\textrm{g}$/dL) was lower than that of control group(1.44$\mu\textrm{g}$/dL)(P<0.05). 4. Milk production of cows cooled with a sprinkler and fan cooling system was significantly higher than that of no cooling system (P<0.0l). 5. Lactose, protein and solid-not-fat content of milk were not changed by the treatments. Milk fat content of the control(3.23%) was low compared with the treatment group(3.38%). Somatic cell count was reduced by 26.63% in the treatment. The results indicate that a sprinkler and fan cooling systems can provide an effective means to relieve heat stress and enhance productivity of lactating Holstein cows during hot and humid summer season.