The effects of drying temperature on the microstructure of porous W fabricated by the freeze-casting process of tert-butyl alcohol slurry with WO3 powder was investigated. Green bodies were hydrogen-reduced at 800oC for 1 h and sintered at 1000oC for 6 h. X-ray diffraction analysis revealed that WO3 powders were completely converted to W without any reaction phases by hydrogen reduction. The sintered body showed pores aligned in the direction of tertbutyl alcohol growth, and the porosity and pore size decreased as the amount of WO3 increased from 5 to 10v ol%. As the drying temperature of the frozen body increased from -25oC to -10oC, the pore size and thickness of the struts increased. The change in microstructural characteristics based on the amount of powder added and the drying temperature was explained by the growth behavior of the freezing agent and the degree of rearrangement of the solid powder during the solidification of the slurry.

본 연구에서는 지방 산화를 억제하고 품질이 우수한 부세 굴비의 가공법을 개발하기 위해 대두와 멸치의 복합 발효소재를 첨가한 염지제 처리 및 건조 시간에 따른 부세 굴비를 제조하여 품질 특성을 비교하였다. 발효소재 첨가에 따른 염지제와 부세 굴비의 DPPH 및 ABTS 라디칼 소거능은 발효소재의 함량에 따라 증가하였으나, 발효소재 1% 이상에서 부세 굴비의 라디칼 소거능은 유의적인 차이를 보이지 않았다. 발효소재의 함량이 증가할수록 부세 굴비의 아미노태질소 함량은 증가하고 VBN, TBARS, 산가는 감소하는 결과를 나타내나, 발효소재 1% 이상에서 품질의 유의적인 차이가 크지 않으므로 염지제의 발효소재 함량은 1%로 선정하였다. 염지제의 염도에 따른 부세 굴비의 품질을 분석한 결과 염도가 증가할수록 아미노태질소 함량은 증가하고 히스타민, VBN, TBARS, 산가는 감소하는 결과는 나타내며, 염지제의 염도는 품질 개선 효과가 가장 우수한 7% 조건을 선정하였다. 염지 처리 후 건조 시간에 따른 부세 굴비의 품질을 분석한 결 과 건조 시간이 증가할수록 수분은 감소하고 염도, pH, 아미노태질소, 히스타민, VBN, TBARS, 산가는 증가하였다. 그러나 건조 48시간 이하는 수분이 많아 저장성이 낮으며, 건조 96시간에서 히스타민과 산패도의 증가율이 높아지므로 부세 굴비의 건조 시간은 72시간이 적합한 것으 로 판단되었다.

The effect of tert-butyl alcohol (TBA) as a freezing solvent on the pore structure of a porous tungsten body prepared by freeze-drying is analyzed. TBA slurries with a WO3 content of 10 vol% are prepared by mixing with a small amount of dispersant and binder at 30oC. The slurries are frozen at -25oC, and pores are formed in the frozen specimens by the sublimation of TBA during drying in air. After hydrogen reduction at 800oC and sintering at 1000oC, the green body of WO3 is completely converted to porous W with various pore structures. Directional pores from the center of the specimen to the outside are observed in the sintered bodies because of the columnar growth of TBA. A decrease in pore directionality and porosity is observed in the specimens prepared by long-duration drying and sintering. The change in pore structure is explained by the growth of the freezing solvent and densification.

Centella asiatica (CA) has been used as a nutritional plant as well as a traditional herbal medicine around the world. This study, quality component (proximate composition, total polyphenol, and triterpenoid compound), and antioxidant and anti-inflammatory activities of CA dried using various methods were investigated. Proximate compositions of CA with different drying methods included a large amount of carbohydrates, crude protein, crude ash, and crude fiber. Among the drying methods, cold drying provided the highest total polyphenol content and antioxidant activity, while hot-air drying at 75℃ provided the lowest total polyphenol content and antioxidant activity. In addition, when the major triterpenoid compounds of CA were analyzed, the highest content of asiaticoside of triterpenoid glycoside was obtained with all drying methods. With respect to the total triterpenoid, the highest content was obtained with cold drying (68.8 mg/g) whereas natural drying (31.4 mg/g) provided the lowest content. In anti-inflammatory activity of LPS-stimulated RAW 264.7 cells, EtOH extract of cold drying showed a significantly higher inhibitory activity in comparison to the other drying methods. In conclusion, it is considered that the cold drying method is suitable for industrial preparation of functional materials with high physiological ingredients, and antioxidant and anti-inflammatory activities from CA.

This field evaluated the effect of different yields on the drying rate of Italian ryegrass (“Kowinearly”, Lolium multiflorum Lam.) hay during the spring season. The experiment was performed at Hwaseong, 2015. The different yields of the plot were selected by growth and development check. Three treatments were 35 t/ha(Y1), 45 t/ha(Y2), and 60 t/ha(Y3). After harvest with conditioner, it was conducted tedding 1/day. It was investigated patterns for changes in moisture content. The changes in moisture content were respectively Y1 from 78.9% to 14.4%, Y2 from 79.1% to 18.3%, and Y3 from 77.9% to 25.5% for 5days. It was no different significantly for changes in moisture content by yields from 1st day ~ 2nd day, But It was different significantly from 3rd day to 5th day. the content of neural detergent fiber(NDF) and acid detergent fiber(ADF) were respectively about 34%, 59%, regardless of yields (P>0.05). Crude protein of Yields Y1, Y2, and Y3 were respectively 6.9%, 8.7%, and 9.4% (P<0.05). The result of this study that the higher yields, the slower it dried. The Quantity is a factor to effect on drying rate.

The feasibility of infrared assisted freeze drying (IRAFD) was evaluated for shelf stable sea cucumber to improve the traditional drying methods such as freeze drying (FD), vacuum drying (VD) and hot air drying (AD, 60, 80, 100oC). Infrared (IR) radiant energy was provided to accelerate the drying rate of freeze drying (FD). IRAFD had the most rapid drying rate among IRAFD, FD and VD. IRAFD showed drying time of 13.7 h followed by VD (18.7 h) and FD (24.3 h). In the final moisture content of sea cucumber, it decreased down to 3.25% at IRAFD. However, FD and VD could not reduce down the moisture content of sea cucumber below 7%. Quality attributes of AD sea cucumber were not acceptable with very low restoration rate and excessive hardness. For example, AD 100 had very low weight restoration rate of 23% and hardness of 22 N. IRAFD showed quite high restoration rates (weight: 50%, width: 82%, length: 91%) and acceptable hardness of 3.1 N. IRAFD consumed the minimal electrical energy of 120 kJ as compared to 209 kJ of FD. This study showed the potential application of IRAFD to produce the shelf stable dried sea cucumber with microbial safety.

Powderization is a promising way to enhance the usability of fruits. Persimmon is one of the most popular fruits in Korea, but its usability is quite limited due to its high moisture content and seasonal availability. The objective of this study is to powderize a persimmon extract by spray drying and to examine the effects of resistant maltodextrin (RMD) and its mixtures with gum arabic (GA) as biopolymeric drying aids on the yield, moisture content, and water activity of resulting persimmon powder. Maltodextrin (MD) and its mixtures with GA were also used for comparison purpose. The feed solutions for spray drying were prepared by adding RMD, MD, GA or their mixtures (RMD:GA=9:1, 8:2, 7:3, 6:4, and 5:5; MD:GA=5:5 and 1.7:8.3) to persimmon extract at a concentration of 30% (w/w) (40% (w/w) total solid). The inlet temperature, air flow rate, atomizing pressure, and feeding rate for spray drying were set as 140 °C, 0.40 m3/min, 100 kPa, and 270 mL/h, respectively. Among the three biopolymers, the highest drying yield (51%) was obtained when RMD was added, followed by GA-added (34%) and MD-added (21%) powders. However, the RMD-added powder was sticky and caused bag filter blockage. Among the biopolymer mixtures, the highest yield (56%) was obtained when the RMD–GA mixture (7:3) was added, and no serious powder stickiness was visually observed. The powder prepared with RMD or MD only yielded very low values of moisture content (1.5-2.0%) and water activity (0.09-0.10), and the values increased when GA was added together. This study demonstrated that the RMD–GA mixture is an effective drying aid for the spray drying of persimmon extract, which is highly sticky and not able to be spray-dried alone.

The purpose of this study was to investigate the effects of nine times repetitive steaming and drying process Sunsik diets on antioxidant activity in obese mice fed high fat diets to prevent oxidative stress, using drying materials comprising 23 kinds of cereals (61.5%), beans (30.0%), sweet potato and potato (3.0%), fruits (2.0%), vegetables (3.0%), and stevioside, a natural sweetener (0.5%). We produced three samples: the experimental group was classified into the normal diet group (control), the high fat diet group (HF), and the high fat diet group + the Sunsik group (3HFS, 7HFS, 9HFS) fed to the mice for eight weeks. As a result, the serum, liver lipid peroxide, and nitric oxide levels were significantly higher in the HF group than in the C group at p<0.05 level, and the NO level was lower in the Sunsik supplemented groups. The antioxidant enzyme catalase activity significantly decreased in the HF group at the p<0.05 level compared to the C group. The total antioxidant activity of the C group was significantly higher in serum, liver, and kidney tissues than the HF group (p<0.05). The anthocyanin level in liver and spleen tissue was significantly higher in the group fed Sunsik than in the HF group.

This study was conducted to develop a high-moisture food waste dryer that uses steam as a direct heat source to improve the drying speed. Another objective was to verify its performance through experiments. A dryer with a drying capacity of 10,000 kg/hr, which uses steam from an incineration plant as a drying heat source, was fabricated. The performance and applicability of the dryer were verified through drying experiments, in which the food waste collected from large restaurants near the incineration plant was used as the experimental material. The drying experiment results showed that the input steam temperature increased by 21℃ from approximately 145℃ to 166℃ compared to the case in which drying was performed by converting steam into heated air. The drying speed increased by 1.5 times from approximately 0.63 to 0.94 %/hr, and drying up to approximately 20%(wb) moisture content was possible. The drying energy rate, which represents the ratio of the energy consumed for drying to the input energy, increased by approximately ten times from 7.17% to 70.87%. The total drying time still remained approximately 100 hr due to the re-condensation of moisture. When steam was directly used as a drying heat source to improve the drying speed of food waste containing high moisture, the drying speed, water content after drying, and drying energy rate were clearly improved compared to the case in which steam was converted into heated air for use. Therefore, it was deemed necessary to develop a dryer that directly uses steam from an incineration plant for drying. To shorten the total drying time, it is necessary to develop a device that solves the problem of moisture condensation in the dryer.

The effect of sublimable vehicles on the pore structure of Cu fabricated by freeze drying is investigated. The 5 vol% CuO-dispersed slurries with camphene and various camphor-naphthalene compositions are frozen in a Teflon mold at -25oC, followed by sublimation at room temperature. After hydrogen reduction at 300oC and sintering at 600 °C, the green bodies of CuO are completely converted to Cu with various pore structures. The sintered samples prepared using CuO/camphene slurries show large pores that are aligned parallel to the sublimable vehicle growth direction. In addition, a dense microstructure is observed in the bottom section of the specimen where the solidification heat was released, owing to the difference in the solidification behavior of the camphene crystals. The porous Cu shows different pore structures, such as dendritic, rod-like, and plate shaped, depending on the composition of the camphornaphthalene system. The change in pore structure is explained by the crystal growth behavior of primary camphor and eutectic and primary naphthalene. Keywords: Porous Cu, Pore structure

Porous Cu-14 wt% Co with aligned pores is produced by a freeze drying and sintering process. Unidirectional freezing of camphene slurry with CuO-Co3O4 powders is conducted, and pores in the frozen specimens are generated by sublimation of the camphene crystals. The dried bodies are hydrogen-reduced at 500oC and sintered at 800oC for 1 h. The reduction behavior of the CuO-Co3O4 powder mixture is analyzed using a temperature-programmed reduction method in an Ar-10% H2 atmosphere. The sintered bodies show large and aligned parallel pores in the camphene growth direction. In addition, small pores are distributed around the internal walls of the large pores. The size and fraction of the pores decrease as the amount of solid powder added to the slurry increases. The change in pore characteristics according to the amount of the mixed powder is interpreted to be due to the rearrangement and accumulation behavior of the solid particles in the freezing process of the slurry.

To increase the functional material content of soybean, a repetitive steaming and drying process was used. We investigated the changes in the total polyphenol content, the antioxidant activity, and the angiotensin-Ⅰ converting enzyme (ACE) inhibition in soybean following nine rounds of steaming and drying. Soybean was steamed 9 times for 2 h and then dried 9 times from 55℃ to 73℃ for 3 h. The total polyphenol content in the soybean reached a maximum value of 60.47 mg GAE eq./100 g at 73℃ while the total polyphenol content in the raw soybean reached 25.17 mg GAE eq./100 g. In the raw soybean samples, the DPPH radical scavenging activity (5 mg/mL) was 8.04% but it increased by 43.29% after drying 9 times to 73℃. ABTS radical scavenging activity also improved following 9 rounds of steaming and drying. ACE inhibitory activity of the soybean dried 9 times at 73℃ was 58.94% at 10 mg/mL. These results showed that steaming and drying soybean 9 times enhanced the antioxidant activity and the ACE inhibitory activity of soybean. Therefore, more research on the biological and anti-hypertensive activity of soybean using this steaming and drying method is necessary.

The purpose of this study was to provide the basic data of butternut squash (Cucurbita moschata) according to the drying methods. The proximate composition and chromaticity of freeze-dried and hot air-dried Cucurbita moschata powders were evaluated, and the antioxidant effects of these ethanolic extracts were analyzed by DPPH, ABTS, FRAP, reducing power activity, total phenolic, and flavonoid content. As a result, Cucurbita moschata was revealed to have high carbohydrate and crude protein contents, while crude ash and crude fat contents were relatively low. Also, it was confirmed that the hot air-dried Cucurbita moschata had lower L, a, and b values than the freeze-dried Cucurbita moschata. Additionally, as a result of analyzing the antioxidant activity of Cucurbita moschata ethanolic extracts, hot air-dried Cucurbita moschata ethanolic extract showed significantly superior antioxidant activity than freeze-dried Cucurbita moschata ethanolic extract. Also, hot air-dried Cucurbita moschata ethanolic extract was revealed to have a higher polyphenol content, but slightly lower flavonoid content than freeze-dried Cucurbita moschata ethanolic extract. Based on the data from this study, further experiments on Cucurbita moschata material are necessary.