• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.12
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• pp.1627-1631
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• 2008

This study was to analyze the physiology activity of barley leaf extract using different drying methods. Yield of RL (raw leaf) and barley leaves dried did not show significant difference by various drying methods. There was no significant difference in total phenolic content by dry method. However, total flavonoid content was high in HD (dried after heat treatments) barley leaf after RL. There was no significance in barley leaf dried by SD (dried in the shade), FD (vacuum freeze dried) and MW (dried by microwave) after the microwave. Superoxide dismutase-like activity was high over 90%: $95.6{\pm}0.3%$ in RL, $94.9{\pm}0.7%$ in HD barley leaf, $92.0{\pm}1.3%$ in SD barley leaf, $91.5{\pm}0.4%$ in FD barley leaf, and $92.5{\pm}0.2%$ in MW barley leaf using the microwave. Significantly higher antioxidant activity was shown as compared to the control group of sesamol ($88.426{\pm}0.802%$), tocopherol ($88.8{\pm}0.6%$), and BHT ($86.6{\pm}0.8%$). Also, except for RL and MW barley leaf, all showed over 80% peroxyl radical scavenging activity and over 90% inhibition rate of xanthine oxidase. The results of this study show that total phenolic content and total flavonoid content by dry method were dependent on the drying temperature with no impact on antioxidant activity.

• Applied Chemistry for Engineering
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• v.29 no.6
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• pp.703-709
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• 2018

Dielectric heating materials were prepared through the thermal treatment for composites of Li and Zn type precursors that are major materials being responded to microwave under diversified conditions. The prepared heating material samples were analyzed by SEM and it was confirmed that $Li_5Fe_5O_8$ materials being formed on the surface was a major influencing factor for the heating performance. Heating materials improved the moisture removal in a sludge drying facility, for example, the moisture content of 25 v/v% sludge decreased to 15.22 v/v%. Accordingly, heating materials were confirmed to directly affect the performance and efficiency of the microwave drying process.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.26 no.1
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• pp.21-25
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• 2014

A drying machine for discarded Citrus scrap was developed in this study. The Citrus produced in Jeju Province was treated as wastes (a) after making a beverage, such as drinking juice, and (b) if the size of the product did not fit with its agricultural product criteria. Various types of drying machine were developed in this study, and different kinds of technologies were combined improve the performance. To enhance the performance, the system was maintained in a vacuum state, and a high frequency micro wave was activated to the waste Citrus scrap, to heat up the moisture inside the Citrus kernels. The frequency of the micro-wave was 2.6 GHz, which is the resonant frequency of the molecules. Experiments were conducted with a vacuum of 50, 100, 150, 300, 500, and 700 mbar. The waste Citrus scrap has two types of status : (a) original scrap, and (b) mixed with blender. As results, specimen (a) shows a 0.13 g/sec evaporation rate, while specimen (b) shows a 0.19 g/sec rate, at 50 mbar of environment vacuum condition. For the drying efficiency, specimens (a) and (b) show 0.15 g/W and 0.24 g/W, respectively.

• Journal of the Korean Society of Food Culture
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• v.34 no.5
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• pp.637-644
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• 2019

The purpose of this study was to optimize the mandarin dry chip manufacturing using a response surface methodology. The experiment was designed based on a CCD (Central Composite Design), and the independent variables were the drying temperature ($X_1$, $50-90^{\circ}C$), drying time ($X_2$, 12-36 hours), and microwave pretreat time ($X_3$, 0-4 minutes). The results of appearance ($Y_5$), color ($Y_6$), taste ($Y_8$) and overall acceptance ($Y_{10}$) were fitted to the response surface methodology model ($R^2=0.86$, 0.88, 0.89, and 0.84, respectively). Increasing the drying temperature and microwave treatment time were negatively evaluated for consumer acceptance. On the other hand, a high value of consumer acceptance was evaluated when the drying time was more than 24 hr. Therefore, the optimal conditions of $X_1$, $X_2$, and $X_3$ were $52.989^{\circ}C$, 24 hr, and 1 min, respectively. Under these optimal conditions, the predicted values of $Y_5$, $Y_6$, $Y_8$, and $Y_{10}$ were 5.066, 5.338, 5.063, and 5.339, respectively.

• Korean Journal of Plant Resources
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• v.35 no.4
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• pp.428-434
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• 2022

Glycyrrhizae Radix is an herbal medicine vulnerable to fungi. So there are regulations on mycotoxins. Therefore, in this study, the affect of various drying methods and additional gamma irradiation (10 kGy) was studied to suppress the microbial generation of Glycyrrhizae Radix. As a result of detecting and comparing microorganisms using the dry film method for samples prepared by each of natural, hot air, freezing, microwave drying and gamma irradiation, the affect of reducing microorganisms by microwave drying and gamma irradiation was confirmed. There was no statistically significant change in the content of the active compounds between the treatment groups.

• Journal of the Mineralogical Society of Korea
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• v.21 no.2
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• pp.193-200
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• 2008

We tried to evaporate and dry the moisture contained Flue gas desulfurization gypsum and phosphogypsum by using the microwave directly. In the result of the heating to the Flue gas desulfurization gypsum and phosphogypsum using 2.45 GHz microwave which was created by magnetron 700 W, 1,000 W and 1,700 W, respectively. According to the increasing the microwave output intensity from 700 W to 1,700 W, the evaporate time of moisture was shortened from 10 to 3 minutes. Gypsum were changed to calcium sulfate hemihydrate. However, ${\beta}$-calcium sulfate hemi-hydrate were not changed to anhydrite.

• Korean Journal of Veterinary Research
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• v.47 no.2
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• pp.203-207
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• 2007

Conventional processing of biological materials including nematode parasites for scanning electron microscopy includes fixation with glutaraldehyde and osmium, followed by dehydration in an ascending grade of ethanol, and finally freeze drying. This procedure takes about 8 to 12 h depending on the characteristics of samples. Microwave irradiation of 2,450 MHz enhance the action of cross-linking fixatives and can greatly accelerate various stages of tissue processing. In this study, samples of nematode parasites, Setaria digitata, were fixed by a combination of conventional chemical fixation and the microwave irradiation during the process. The microwave irradiation was also incorporated in the serial dehydration process with ethanol. The complete procedure from the initial fixation to the completion of dehydration with ethanol was reduced to 1 h with good preservation of the ultrastructural details of the specimens.

• Environmental Engineering Research
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• v.24 no.4
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• pp.591-599
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• 2019

To convert sewage sludge to energy, drying-gasification characteristics during microwave heating were studied. During the gasification of carbon dioxide, the main products were gas, followed by char, and tar in terms of the amount. The main components of the producer gas were carbon monoxide and hydrogen including a small amount of methane and light hydrocarbons. They showed a sufficient heating value as a fuel. The generated tar is gravimetric tar, which is total tar. As light tars, benzene (light aromatic tar) was a major light tar. Naphthalene, anthracene, and pyrene (light polycyclic aromatic hydrocarbon tars) were also generated, but in relatively small amounts. Ammonia and hydrogen cyanide (precursor for NO_x) were generated from thermal decomposition of tar containing protein and nitrogen in sewage sludge. In the case of sludge char, its average pore diameter was small, but specific area, pore volume, and adsorption amounts were relatively large, resulting in superior adsorption characteristics.

• International Journal of Industrial Entomology and Biomaterials
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• v.42 no.1
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• pp.14-20
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• 2021

Mulberry was dried with low temperature vacuum dryer using microwave. The nutritional compositions of microwave-dried mulberry including proximate composition, sugar content, mineral content, total phenolic, flavonoids, and anthocyanin, beta-carotene, vitamin C, and amino acid composition were measured. Sugar contents of mulberry were 42.6 mg/100g (Cheongilppong) and 43.27 mg/100g dw (Gwasang No. 2). The main components of mulberry sugars were fructose and glucose. Mineral analysis showed that K, P, Ca, and Mg were abundant regardless of mulberry cultivars.

• Journal of agriculture & life science
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• v.43 no.6
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• pp.111-115
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• 2009

This study was conducted to develop the ultrasonic dryer because present drying methods (heat convection, microwave, vacuum, etc.) could not improve the drying consumption energy, decrease of quality and drying ratio by physical limitation. The drying tests were conducted with four levels (No. 1 only non-heated air, No. 2 only ultrasonic, No. 3 only heated air and No. 4 ultrasonic with heated air) and measuring weight of samples after drying carrot and ginseng slices for 30 minutes. The result of test is that the drying ratio was highest in the level of No. 4 ultrasonic with heated air. The sliced carrot's drying ratio was 22.4% (w.b.)/h and sliced ginseng's drying ratio was 3.8% (w.b.)/h. The discoloration and twist of samples was appeared on using only heated air like No. 3.