• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.5
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• pp.695-701
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• 2015

This study was conducted to evaluate the effects of drying and extraction methods on antioxidant activity and total phenol content of Gnaphalium affine D. DON (GA). Hot-air, shade-drying, and freeze-drying were used for drying, after which magnetic stirring and ultrasonification were applied. Extracting solvents were water, 80% ethanol, and 80% methanol. Total phenol content was highest in 80% ethanol extract of freeze-dried and stirred GA. Total flavonoid content was highest in 80% methanol extract of freeze-dried and stirred GA. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity was higher in 80% methanol and 80% ethanol extracts than in water extract. 2,2-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activity was highest in 80% ethanol extract of shade-dried and ultrasonicated GA. Reducing power was generally higher in 80% methanol extract than in 80% ethanol and water extracts of GA. Total phenol and total flavonoid contents were highly correlated with DPPH radical scavenging activity and reducing power, respectively. This result implies that the antioxidant activity of GA can be attributed to phenol compounds such as flavonoids. Conclusively, phenol compounds such as flavonoids are responsible for the antioxidant activity of GA, and there was no significant effect of drying and stirring conditions on antioxidant activity of 80% ethanol. Meanwhile, DPPH radical scavenging activity of water extract and reducing power of 80% methanol extract were higher in hot-air and shade-dried GAs than in freeze-dried GA.

• Korean Journal of Food Science and Technology
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• v.34 no.5
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• pp.780-786
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• 2002

Optimum condition of the drying process and the changes in aroma components during dehydration were determined for Sarcodon aspratus. The drying curve of mushrooms consisted of short constant rate period followed by long falling rate period. The drying rate increased with increasing drying temperature and air velocity. Results showed that mushrooms dried at $50^{\circ}C$ and air velocity of 1.5 m/sec had the greatest peak area of aroma compound. The aromatic components of the dried mushrooms were 1-octen-3-one, 1-octen-3-ol, 3-octanone, 1-octanol, 2-octen-1-ol, 3-octanol, 3-octanone, 1-octanol, 2-octen-1-ol, and 3-octanol. Peak areas of mushroom alcohol and aromatic compounds of mushrooms including 1-octen-3-ol, 1-octanol, 2-octen-1-ol, 3-octanol decreased significantly, whereas those of 1-octen-3-one and 3-octane increased during the drying period. New unfavorable compounds including butyric acid, propanoic acid, and 3-methyl thiopropanol were formed during the drying period.

• Journal of the Korea Organic Resources Recycling Association
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• v.26 no.2
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• pp.65-73
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• 2018

This study was carried out for 20 days in a bio-drying batch reactor under the blowing conditions of 0.75, 1.00, 1.25, and $1.50L/min{\cdot}kg$ in order to optimize the operating conditions for the bio-drying of food wastes. The decomposition rate of organic matter during the bio-drying operation period was analyzed using modified Gompertz model. The maximum organic degradation (P) was 2.31, 2.52, 2.27 and 1.88 kg at air flow rates of 0.75, 1.00, 1.25 and $1.50L/min{\cdot}kg$, and the maximum organic degradation rate was 0.33, 0.45, 0.28, and 0.18 kg/day at 1.00, 1.25 and $1.50L/min{\cdot}kg$, respectively, showing excellent organic decomposition efficiency at a air flow rate of $1.00L/min{\cdot}kg$. The lag growth phase time (${\lambda}$) of the bio-drying reactor was 2.10, 1.48, 1.15, and 1.06 days at 0.75, 1.00, 1.25 and $1.50L/min{\cdot}kg$, respectively. The water removal rate in the operation of bio-drying reactor of food waste increased with the increase of air flow rate from the early stage of bio-drying to the middle stage, and the highest water removal rate was observed at the air flow rate of $1.00L/min{\cdot}kg$ at the end of bio-drying. The optimum air flow rate condition of bio-drying reactor was $1.00L/min{\cdot}kg$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.11 no.1
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• pp.37-43
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• 1982

Constant rate period, falling rate period and diffusion coefficient using filefish fillet as sample during drying in hot air drier were determined under controlled conditions of temperature, humidity and air velocity. Drying rate curve consisted of a short period of constant rate and two stages of falling rate period. When 1 to 3m/see of air velocities were applied, diffusion coefficients were in the range of 1.9130 to $2.6187\;{\times}\;10^{-6}\;\textrm{cm}^2/sec$ at $50^{\circ}C$. 2.4806 to $3.5342\;{\times}\;10^{-6}\;\textrm{cm}^2/sec$ at $60^{\circ}C$ and 4.3405 to $5.3042\;{\times}\;10^{-6}\;\textrm{cm}^2/sec$ at $70^{\circ}C$, respectively. Available lysine content was decreased by 15%. 16% and 20% in the fillet dried at $50^{\circ}C$, $60^{\circ}C$ and $70^{\circ}C$, respectively.

• Journal of the Korea Concrete Institute
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• v.22 no.1
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• pp.85-91
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• 2010

In this study, the drying shrinkage strains were compared of 24~60 MPa concrete specimens subjected to various curing conditions and measurement methods were compared. And, the applicability of the test and prediction methods were investigated. According to the results, drying shrinkage was significantly reduced in 28 day curing condition. In the sealed curing case, drying shrinkage strain from demolding time was identical to the one of the standard curing case for low strength concrete, however, drying shrinkage strain was greatly increased than the standard case for high strength case because of the effect of autogenous shrinkage. The efficient measurement was possible using the embedded gage for concrete drying shrinkage, but, the measured value by contact gage was lower than the one by the embedded gage. The test results agreed with EC2 model better than the other.

• Journal of the Korean Wood Science and Technology
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• v.45 no.3
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• pp.288-296
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• 2017

In this study, the effect of spray-drying conditions and surfactant addition on the spray-drying yield, morphological characterization, size distribution and re-dispersity in water of spray-dried lignocellulose nanofibril (LCNF) were investigated. The freeze-dried LCNF after solvent exchange had linear fiber morphology with a diameter of 70-300 nm, and the spray-dried LCNF showed rod-like particle morphology. The spray-drying yield and particle size of spary-dried LCNF at $140^{\circ}C$ was highest and smallest, respectively. As LCNF concentration and blowing rate decreased and increased, respectively, the spray-drying yield and particle size were increased. The highest spray-drying yield was found at distearyl dimethyl ammonium chloride (DDAC) addition of 10 phr at $140^{\circ}C$. As the particle size decreased and the DDAC content increased, filtration time of spray-dried LCNF in water was decreased and increased, respectively.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.71.1-71.1
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• 2010

고분자 전해질 연료전지(PEMFC) 내의 기체확산층(GDL)은 셀 내의 물 관리에 중요한 역할을 수행한다. 일반적으로 다공성 기제(GDBL) 위에 미세기공층(MPL)을 코팅한 2층 구조의 기체확산층이 사용되는데, 이 미세기공층은 카본파우더와 테프론의 혼합물로 이루어져 있으며 촉매층에서 발생한 물을 셀 밖으로 빠르게 배출하는 역할을 수행한다. 본 연구에서는 다양한 기공분포를 갖는 미세기공층을 제조하여 고분자 전해질 연료전지 성능에 미치는 영향을 분석하였다. 미세기공층 슬러리내에 암모늄염 계열의 기공형성제를 혼합하여 다공성 기제 위에 코팅한 후 다양한 온도조건에서 건조함에 따라 기공분포가 다른 미세기공층을 제조하였다. 이렇게 제조된 미세기공층의 물성은 수은기공도계, FE-SEM, 자체적으로 제조한 기체투과도 측정 장치를 사용하여 측정하였으며, 단위 전지 성능 측정은 두 개의 가습조건(RH100%, RH50%)에서 실시하였다. 기공분포 측정결과 건조온도가 높은 미세기공층은 건조온도가 낮은 미세기공층에 비해 직경이 1,000 - 20,000 nm 인 대공극(macropore)의 수가 많지만, 직경이 100 nm 이하의 미세공 (micropore)의 수가 적은 것을 확인하였다. 전지성능 측정 결과 고가습 조건 (RH100%)에서는 미세공 (micropore)이 발달한 미세기공층을 포함한 기체확산층을 사용한 경우 가장 우수한 성능을 보여고, 저가습 조건 (RH50%)에서는 대공극 (macropore)이 발달한 미세기공층을 포함한 기체확산층을 사용한 경우 가장 우수한 성능을 나타내었다. 이는 물배출에 유리한 미세공 (micropore)의 성질과 원료 기체의 이동에 유리한 대공극(macropore)의 성질에 의한 것으로 판단된다. 따라서 셀 운전 가습조건에 따라 최적화된 기공구조를 갖는 미세기공층을 사용함으로써 셀 운전 성능을 향상 시킬 수 있을 것으로 예상된다.

• Korean Journal of Food Science and Technology
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• v.42 no.1
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• pp.45-49
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• 2010

To reduce the astringent taste of lotus root, the effects of various treatment methods such as drying, soaking, steaming and roasting on the physicochemical properties and sensory characteristics were investigated. The following process conditions were selected: 1) drying (D), 2) soaking followed by drying ($SK{\rightarrow}D$), 3) steaming followed by drying ($ST{\rightarrow}D$), 4) drying followed by roasting ($D{\rightarrow}R$), 5) soaking and then drying followed by roasting ($SK{\rightarrow}D{\rightarrow}R$), 6) steaming and then drying followed by roasting ($ST{\rightarrow}D{\rightarrow$}. The tannin content of the lotus root was lowest when it was treated by steaming followed by drying ($ST{\rightarrow}D$). The astringent taste of lotus root was reduced by steaming, and the roasted taste was improved by roasting in terms of sensory and flavor characteristics. Consequently, lotus root treated by steaming and then drying followed by roasting ($ST{\rightarrow}D{\rightarrow}R$) showed the highest preference with respect to astringent and roasted taste.

• Korean Journal of Plant Resources
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• v.8 no.2
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• pp.115-125
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• 1995

The moistures, colors and flavors of red pepper were analyzed to observe the changes of the qualities of red pepper with various conditions of drying. The moisture was 11.8%, known as optimal condition for storing red pepper, where dried at $50^{\circ}C$ for 36 and 48 hours. The color of red pepper air-dried at 50% for 48 hours was estimated to be the most execllent in comparison of sun drying and air drying. The optimal absorbances of hexnae extract from red pepper were examined. The ratios between the absorbances at 280nm and at the typical wavelengths of caretenoids(430nm, 450nm, 474nm) were from 2.5-3.4 and these wete also confirmed by the sight of the eye. Hexane fraction showed more peaks of flavors than benzene fraction and both of the two were silylated by with BSTFA to analyze the flavors by GC. CG profiles for the compositions of flavors in red perpper are thought to be useful for extimating the quality of favors in red pepper. Eight flavors including benzene dicarbozylic acid, were identified from red pepper and major components of them were oleic palmitic acids. Drying temperatures and times did not have effects on the changes of specific flavor components but did influenced the compositions of them in red pepper.

• Korean Journal of Agricultural Science
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• v.10 no.1
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• pp.118-128
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• 1983

Simulation model of natural air grain drying was discussed and modified to predict the changes of grain moisture content and dry matter loss of rough rice drying. The modified simulation model was then validated using actual test data. A series of simulated drying tests using official weather data for 15 years from Beaumont, Texas, was taken to make minimum airflow rate and maximum bed depth of rough rice drying by natural air, under different conditions of initial moisture content of rough rice, airflow rate and harvest date.