• Journal of the Korean Society of Food Culture
• /
• v.34 no.2
• /
• pp.224-232
• /
• 2019

This study evaluated the physicochemical and microbial quality characteristic of seasonal commercial kimchi for hygienic safety levels. The pH of seasonal commercial kimchi was 3.84-6.36 and the titratable acidity and salinity of the samples were 0.21-1.16 and 1.19-1.54%, respectively. The content of nitrate and nitrite in the commercial kimchi were lower in the spring and summer, which was affected by acidic condition of the kimchi depending on fermentation. Heavy metal contents in commercial kimchi are not an issue because they were detected only at very low levels. The total aerobic bacteria and coliforms counts ranged from 5.25 to 8.44 Log CFU/g and 0.00 to 5.08 Log CFU/g, respectively. The total aerobic bacteria and coliforms were detected more in summer than in the other seasons. E. coli was detected in three of the samples tested. Food-borne pathogens were not detected in any of the samples except for B. cereus. B. cereus was detected in the fall in more than 70% of samples. These results suggest that commercial kimchi distributed in the fall maintain the quality properties and the microbiological safety of kimchi compared to the other seasons. Therefore, further studies as an effective distribution system for the particular seasons will be needed to guarantee the hygienic safety levels of commercial kimchi required by the consumers.

• Food Engineering Progress
• /
• v.21 no.1
• /
• pp.22-28
• /
• 2017

Ginger was steamed at $121^{\circ}C$ and $1.5lb/in^2$ for 30 min, dried at $60^{\circ}C$ for 12 h, and each step was repeated nine times. During processing, the lightness ($L^*$ value) and yellowness ($b^*$ value) decreased from $85.65{\pm}0.33$ and $26.99{\pm}0.20$ in the non-treated ginger to $56.91{\pm}0.25$ and $16.69{\pm}0.06$ in ginger treated for the ninth treatment. On the other hand, redness ($a^*$ value) increased from $-1.51{\pm}0.03$ to $7.34{\pm}0.08$ on the eight treatment and then decreased to $7.21{\pm}0.04$ on the ninth theatment. The contents of 6-gingerol decreased from $3.257{\pm}0.067mg/g$ in the non-treated ginger to $0.567{\pm}0.036mg/g$ on the theatment, whereas the contents of 6-shogaol increased from $1.299{\pm}0.050mg/g$ to $2.999{\pm}0.089mg/g$ on the sixth treatment and decreased to $2.099{\pm}0.039$ on the ninth treatment. The contents of 10-gingerol decreased slightly from $1.106{\pm}0.125mg/g$ to $0.806{\pm}0.026mg/g$. Unlike the 6- and 10-gingerol, the contents of 8-gingerol did not change greatly, with values between $0.916{\pm}0.005mg/g$ and $1.106{\pm}0.005mg/g$ being observed during processing. The tyrosinase inhibitory activities were increased from $43.42{\pm}11.45%$ in the non-treated ginger to 100% on the sixth treatment and then decreased to $51.98{\pm}7.36%$ on the theatment. The antioxidative activity was retained during processing.

• Clean Technology
• /
• v.25 no.1
• /
• pp.1-6
• /
• 2019

Effects of the Cu and K addition and the reduction condition of Fe-based catalysts for Fischer-Tropsch reaction are studied in a continuous flow reactor in this research. The catalysts for the reaction were prepared by homogeneous precipitation followed by incipient wetness impregnation. Physicochemical properties of the $Al_2O_3$ supported Fe-based catalysts are characterized by various methods including X-ray diffraction (XRD), temperature programmed reduction (TPR), and scanning electron microscopy (SEM). Catalytic activities and stabilities of the Fe/Cu/K catalyst are investigated in time-on-stream for an extended reaction time over 216 h. It is found that a reduction of the catalysts using a mixture of CO and $H_2$ can promote their catalytic activities, attributed to the iron carbides formed on the catalysts surface by X-ray diffraction analysis. The addition of Cu induces a fast stabilization of the reaction reducing the time to reach at the steady state by enhancement of catalytic reduction. The addition of K to the catalysts increases the CO conversion, while the physical stability of catalyst decreases with potassium loading up to 5%. The Fe/Cu (5%)/K (1%) catalyst shows an enhanced long term stability for the Fischer-Tropsch reaction under the practical reaction condition, displaying about 15% decrease in the CO conversion after 120 h of the operation.

• Journal of the Korean Applied Science and Technology
• /
• v.36 no.2
• /
• pp.668-675
• /
• 2019

Fine dust in air pollutants is recognized as one of the most serious social environmental problems. Most of the NOx is generated in a combustion process such as that of a coal-fired power plant, and therefore efficient elimination of the NOx from the coal-fired power plants is needed. This study investigates the removal efficiency of using $TiO_2$, a photocatalyst, to remove NOx by Selective Catalytic Reduction (SCR). To evaluate the NOx removal efficiency, $TiO_2$ catalyst and phosphate binder were mixed on the surface of the $Al_2O_3$ substrate with the exothermic agent, and the substrate was heat-treated. The NOx removal efficiency of the catalysts was evaluated according to the temperature, and XRD, SEM, TG-DTA and BET analyzes were performed to investigate the physicochemical properties of the catalysts. NOx removal efficiency was 58.7%~65.9% at 20min, 63.7~66.0% at 30min with temperature change according to time($250^{\circ}C{\sim}500^{\circ}C$). The $TiO_2$ used in the SCR for NOx removal is judged to have the most efficient removal efficiency at $300^{\circ}C$.

• Journal of Life Science
• /
• v.29 no.10
• /
• pp.1136-1143
• /
• 2019

The purpose of this study was to investigate the biological activities of an aqueous extract of Angelica gigas (Ag) fermented by Saccharomyces cerevisiae (Sc). First, the soluble solids of the F/3 group, in which the Ag was fermented by Sc for 3 days, decreased from $1^{\circ}Bx$ to $0.9^{\circ}Bx$. On the other hand, the pH increased with the number of days of fermentation. The result of a TLC experiment confirmed that it gradually decomposed into a low-molecular weight sugar form upon fermentation. The total phenolic compounds and flavonoid contents were higher in the fermented group than in the non-fermented group. K and Ca contents were increased by fermentation in the following order: F/3, NF, and F/0 groups. Decursin and decursinol angelate contents were highest in the F/3 group. The DPPH (${\alpha}$, ${\alpha}{\prime}$-diphenyl-${\beta}$-picrylhydrazyl) radical scavenging activity of the NF, F/0, and F/3 groups were 41.89%, 39.51%, and 60.26%, respectively. The inhibition activities of tyrosinase and lipoxygenase were stronger in the F/3 group than in the NF group. This experiment showed that the fermentation of Ag Nakai can lead to an increase in its antioxidant ability, physiological activity, whitening and anti-inflammatory effects. Thus, this oriental herbal medicine can be developed into a functional material that can be utilized in the development of cosmetic products in future.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.27 no.3
• /
• pp.27-39
• /
• 2019

In this study, thermal-alkali pre-treatment (THAP) optimal condition and co-digestion efficiency with THAP of the mixture food waste and sewage sludge were evaluated for improving the performances of co-digestion for mixed food waste and sewage sludge. The optimal condition of THAP was evaluated for solubilization COD, CST(Capillary Suction Time), TTF(Time to Filter), and volatile fatty acids (VFAs) with THAP temperature and NaOH concentration. In addition, the co-digestion of mixed food waste and sewage sludge were evaluated using biochemical methane potential (BMP) test. The optimal THAP reaction temperature and NaOH concentration of food waste and sewage sludge were $140^{\circ}C$ and 60 meq/L to solubilization COD over 20%, CST and TTF under 60sec and VFAs concentration over 12,000 mg-COD/L, respectively. The optimal condition of co-digestion of mixed food waste and sewage sludge equal to THAP condition. Therefore, it was determined that the optimal condition of THAP reaction temperature and NaOH concentration for co-digestion of mixed food waste and sewage sludge were $140^{\circ}C$ and 60 meq/L, respectively.

• Journal of Korean Society on Water Environment
• /
• v.35 no.3
• /
• pp.224-233
• /
• 2019

Nitrogen components in liquid manure can reduce safety and quality of environment harmfully. To minimize the environmental risks of manure, understanding fate of manure in environment is necessary. This study aimed at investigating applicability of a simplified Level III fugacity model for simulating $NH_3-N$ component to analyze environmental fate and transport of $NH_3-N$ in liquid manure and to provide basis for improving management of N in the liquid manure system and for minimizing the environmental impacts of N. The model simulation conducted for four environmental compartments (air, water, soil, and rice plants) during rice-cropping to trace $NH_3-N$ component and provided applicability of the Level III fugacity model in studying the environmental fate of $NH_3-N$ in manure. Most of $NH_3-N$ was found in water body and in rice plants depending upon the physicochemical properties and proper removal processes. For more precise model results, the model is needed to modify with the detailed removal processes in each compartment and to collect proper and accurate information for input parameters. Further study should be about simulations of various N-typed fertilizers to compare with the liquid manure based on a modified and relatively simplified Level III fugacity model.

• Food Engineering Progress
• /
• v.21 no.2
• /
• pp.116-125
• /
• 2017

This study aims to make extruded rice snack with high quality in texture and nutrition by adding mealworm. Addition of the mealworm has the merit to fill in high-quality protein and unsaturated fatty acids which are insufficient in rice. Thus, the physicochemical properties were investigated through the process of extrusion cooking. As the extrusion process varied, the die temperatures were set to $120^{\circ}C$ and $130^{\circ}C$. Also, the moisture contents were adjusted to 30% and 35%. The specific length, the expansion ratio, and the water absorption index increased as the added content of mealworm became higher. On the contrary, the density, the breaking strength, the apparent elastic modulus, and the water solubility index decreased. As mealworm and moisture content increased, DPPH radical scavenging activity significantly increased but the rancidity decreased. As a result, the addition of mealworm to the extruded rice snack was effective in improving texture, nutrition, and antioxidation.

• Korean Chemical Engineering Research
• /
• v.59 no.2
• /
• pp.296-303
• /
• 2021

The objective of this study is to investigate the applicability of a Cu-supported honeycomb catalyst as a catalyst for decomposition of a low toxic liquid propellant based on ammonium dinitramide (ADN). A mixture of copper, lanthanum, and alumina was supported on the honeycomb support by wash coating to prepare a Cu-La-Al/honeycomb catalyst. We elucidated that the effect of metal loading on the physicochemical properties of Cu-La-Al/honeycomb catalyst and catalytic performance in decomposition of the ADN-based liquid propellant. As the number of wash coatings increased, the amount of active metal Cu was increased to 4.1 wt%. The BET surface area of the Cu-La-Al/honeycomb catalyst was in the range of 3.1~4.1 ㎡/g. The micropores were hardly present in Cu-La-Al/honeycomb catalysts, however, the mesopores and macropores were well developed. The Cu (2.7 wt%)-La-Al/honeycomb catalyst exhibited the highest activity in the decomposition of the ADN-based liquid propellant, which is attributed to the largest surface area, the largest pore volume, and the well-developed mesopores and macropores.

• Journal of Life Science
• /
• v.31 no.2
• /
• pp.149-157
• /
• 2021

Prunus mume Sieb. et Zucc is widely distributed in East Asia (Korea, Japan, and China), and its fruit is often used as a medication and food material. However, because most previous studies have only investigated the state of Prunus mume fruit extract, studies on the various ways of processing this extract are still needed to increase its utilization. In this study, we evaluated the physicochemical properties and physiological activities of spray-dried Prunus mume vinegar powder (SPP). The sugar content, pH, total acidity, and moisture content of the SPP were 8.90 °Brix, 3.19, 1.05%, and 3.07%, respectively. The SPP exhibited significantly high antioxidant activity in terms of DPPH radical scavenging activity (65.55%), reducing power (1.48), and hydrogen peroxide scavenging activity (48.07%). In addition, the SPP remarkably decreased the cell viability of human breast MDA-MB-231 and human skin cancer SK-MEL-28 in a dose-dependent manner. The morphological results of the treatment of MDA-MB-231 cells with SPP were distorted, shrunken cell masses. Furthermore, apoptotic bodies and nuclear condensation formed in the SPP-treated MDA-MB-231 cells. The total polyphenol and flavonoid contents of the SPP were 59.58 ㎍/g (gallic acid equivalent) and 57.56 ㎍/g (quercetin equivalent). The results of this study indicate that SPP, which has antioxidant activity and anticancer effects, can be useful in the development of natural medicines and functional food ingredients.