• Journal of the Korean Applied Science and Technology
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• v.35 no.4
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• pp.1320-1326
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• 2018

This study investigated the antioxidant and neuronal cell protective effects of activity of water and 70% ethanol extracts from Stachys sieboldii Miq. according to different drying method(hot air drying and freeze-drying). The total flavonoid and total polyphenol content in water extracts was significantly higher after freeze-drying compared to hot air drying(p<0.05). DPPH and ABTS radical scavenging were increased in a dose-dependent manner. The DPPH and ABTS radical scavenging activity of water extract were significantly higher after free-drying compared to hot air drying(p<0.05). In a cell viability using MTT, the water extract according to hot air drying and freeze-drying of Stachys sieboldii Miq. showed protective effect against H2O2-induced nurotoxicity. The results suggest that the water extracts of Stachys sieboldii Miq. after freeze-drying has antioxidant activities and may be useful for neurodegenerative disorders.

• Journal of Fisheries and Marine Sciences Education
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• v.20 no.3
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• pp.508-519
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• 2008

Hot air drying is a method that let moistures evaporate by heat exchange between heating air and dry target. This way is dominating more than about 70% of dryers that the use extent is wide fairly, and is established in domestic than dryer that use conduction or radiation etc. Most of research about drying had been emphasized in size of device through analysis for these dry phenomenon plain, heating topology, and aspect of form and so on by dry target's special quality, and research about device development or waste heat withdrawal technology in energy utilization efficiency side is slight real condition. Therefore, in this study, Investigated numerically about thermal efficiency elevation that is leaned against as that change the temperature of inlet and outlet in heat exchanger of the hot air drying tower.

• Korean Journal of Food Science and Technology
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• v.28 no.5
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• pp.814-821
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• 1996

An attempt was made to determine the effects of drying methods including shady air drying, presteamed and shady air drying, microwave drying, and freeze drying on the volatile flavor components of Capsella bursapastoris. Essential oils from the samples were isolated by Simultaneous steam distillation-extraction (SDE) method using diethyl ether as solvent. Concentrated samples were analyzed by gas chromatography (GC) and combined gas chromatography-mass spectrometry (GC-MS). Respective 30, 18, 29, and 26 volatile flavor components were identified in shady air dried samples, presteamed and shady air dried samples, microwave dried samples, and freeze dried samples. The kinds and amounts of volatile flavor components evidently depended upon the drying methods. Trimethyl sulfide was regarded as the most abundant component in shady air dried samples, dimethyl trisulfide in presteamed and shady air dried samples, and phytol in microwave or freeze dried samples.

• Journal of Food Hygiene and Safety
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• v.27 no.4
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• pp.415-419
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• 2012

To know proper drying condition for making a safe Sunsik, uncooked food, microbial and physicochemical characteristics of cereal dried by hot-air drying was investigated. As moisture content of 3 Sunsik samples was reduced to about 8%, protein, carbohydrate, fat and ash content of those was increased. But approximate composition of black bean, black rice and glutinous millete and black bean showed little changes during hot-air drying (30, 40, $50^{\circ}C$). Lightness (L value), redness (a value) and yellowness (b value) was increased after hot-air drying. In case of black rice and glutinous millet, b value and L value wasn't changed individually. When we measured a texture for 3 kinds of raw cereal for, hardness of dried cereals was lower than raw cereals. Hardness of dried cereals was increasd as drying temperature was increased. As results of mocrobiologicl experiment for 3 kinds of sunsik on hot-air drying conditions, total cell count was reduced 2 log - 3 log and other pathogenic microorganism wasn't detected except B. cereus.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.spc1
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• pp.251-254
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• 2006

This study was conducted to identify changes of chemical components affected by different drying method and temperature conditions in leaves and stems of peony plant. Drying methods were the dried air heated $(50^{\circ}C)$, far-red ray $(50^{\circ}C)$, room temperature and oven dry $(50^{\circ}C)$. Drying temperature were 40, 50, 60, 70 and $80^{\circ}C$ on far-red ray dryer. Among the drying methods, the contents of components were the highest in far-red drying and normal temperature drying as compared with air heated drying and oven drying. Among the drying temperature conditions, the contents of components were the highest in drying temperature at $40^{\circ}C$ and decreased in high temperature of $70^{\circ}C\;and\;80^{\circ}C$.

• The Korean Journal of Food And Nutrition
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• v.30 no.3
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• pp.609-617
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• 2017

This experiment was carried out to enhance the availability of blackberry. Since it is difficult to use blackberry as a fresh fruit, we investigated the quality characteristics of blackberry powder obtained by various drying methods (freeze drying and hot-air drying at $40{\sim}80^{\circ}C$). The L- and b-values of freeze-dried powder was higher than hot-air dried powder. The pH (3.2) was lowest and the acidity (14.4%) was highest in freeze-dried powder. In freeze drying, the brix degree was $65.7^{\circ}Bx$, but it increased from $54.7^{\circ}Bx$ to $68.5^{\circ}Bx$ with increasing temperature during hot air drying. The total polyphenol and flavonoids contents were the highest in freeze-dried powder, at 9.3 and 6.2 mg/g, respectively. The levels increased as temperature increased in hot air drying. Anthocyanin content in freeze-dried powder was 8.51 mg/g, while it sharply decreased to 1.17~2.45 mg/g in hot-air drying. Vitamin C content in freeze drying ($979.4{\mu}g/g$) was higher than that in hot-air drying ($48.3{\sim}303.2{\mu}g/g$). The sample concentration required for 50% reduction of DPPH free radical scavenging ($RC_{50}$) was $79.7{\mu}g/mL$ in freeze drying, and showed high antioxidant activity. Also it decreased from $122.4{\mu}g/mL$ to $87.7{\mu}g/mL$ with temperature increase during hot air drying. We therefore conclude from the above results that freeze drying is more suitable for the production of blackberry powder, because this method showed high value of chromaticity, total polyphenol, flavonoid, anthocyanin content, vitamin C and antioxidant activity.

• Food Science of Animal Resources
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• v.42 no.5
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• pp.861-873
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• 2022

The drying of duck blood provides safety and commercial benefits, but each drying method has its own characteristics. Moreover, information on the effects of diverse drying methods on the quality of duck blood is limited. This study aimed to investigate the effects of various drying methods on the chemical and functional properties of duck blood. The physicochemical characteristics and functional properties of duck blood subjected to spray drying (SD), freeze drying (FD), vacuum drying (VD), and hot air drying (HD) were examined. The carbonyl content of FD duck blood powder was the lowest and the thermal stability was higher than that of the other treatments (p<0.05). The gel obtained from spray-dried blood displayed the lowest malondialdehyde content. The hardness, gumminess, and chewiness were the highest in the heat-induced gel prepared from FD duck blood powder (p<0.05). The gel obtained from FD duck blood displayed a denser structure than the other gel samples. Taken together, the FD duck blood exhibited excellent chemical properties and processing suitability.

• Journal of Fisheries and Marine Sciences Education
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• v.20 no.3
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• pp.500-507
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• 2008

Hot air drying is a method that let moistures evaporate by heat exchange between heating air and dry target. This way is dominating more than about 70% of dryers that the use extent is wide fairly, and is established in domestic than dryer that use conduction or radiation etc. Most of research about drying had been emphasized in size of device through analysis for these dry phenomenon plain, heating topology, and aspect of form and so on by dry target's special quality, and research about device development or waste heat withdrawal technology in energy utilization efficiency side is slight real condition. Therefore, in this study, Investigated numerically about thermal efficiency elevation that is leaned against as that change the temperature of inlet and outlet in heat exchanger of the hot air drying tower.

• Food Science and Preservation
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• v.12 no.5
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• pp.442-448
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• 2005

To develop efficient drying method, one of important process in manufacturing of Saengsik, uncooked food, the change of physicochemical characteristics and functional component contents of cereals dried by various drying methods was investigated. The proximate composition and dietary fiber content of rice, brown rice, glutinous rice and barley showed little changes during hot-air drying (50$\circC$, 55$\circC$, 60$\circC$) and freeze-drying. Yellowness(b) value of hot-air dried products was higher than one of freeze-dried products. The content of niacin was 0.77 mg% in milled rice, 1.84 mg% in brown rice, 0.68 mg% in glutinous rice, 1.00 mg% in barely dried by hot-air at 60$\circC$ and was lower than those of other samples. $\beta$-glucan content in barely was not changed by hot-air drying and freeze-drying method. In conclusion, hot-air drying would be recommended for barley having $\beta$-glucan, a kind of functional components and freeze-drying should be used for raw materials having heat-labile components such as niacin.

• Korean Journal of Food Science and Technology
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• v.36 no.1
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• pp.25-31
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• 2004

Characteristics of good-quality red pepper powder produced using $N_{2}$-circulated low-temperature drying method were compared with those made through conventional sun and hot-air drying methods. Kimchi and kochujang were prepared with different types of red pepper powder, and their physicochemical and sensory properties were compared. Results revealed Hunter L (lightness), a (redness), and b (yellowness) values of $N_{2}$-circulated low temperature-dried red pepper were highest. Absorbance of crude capsanthin in hot air-dried red pepper powder ($0.584{\pm}0.001$) was significantly lower than sun-dried ($0.848{\pm}0.001$) and $N_{2}$-circulated low temperature-dried products ($0.832{\pm}0.002$. Use of $N_{2}$-circulated low-temperature drying method resulted in the highest amounts at reducing sugar and total vitamin C. Capsaicin content of $N_{2}$-circulated low temperature-dried products were higher than hot air-dried ones. The aL values of kochujaug made with sun-and low temperature-dried red peppers were higher than that of kochujang made with hot-dried red peppers. Physicochemical and sensory evaluation results showed red pepper powders made using $N_{2}$-circulated low-temperature drying method have the best quality among all samples tested.