• 한국세라믹학회지
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• 제40권8호
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• pp.798-803
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• 2003

In synthesis of nano powders, the hard agglomeration for the synthesized powders occurred during the drying processing. In order to avoid hard agglomeration in particles the freeze drying process was used in this experiment. e fabricated the Yttira-Doped Ceria(YDC) nano powder by co-precipitation. Starting materials used in experiments were the cerium(III) nitrate and yttrium(III) nitrate solution with 야-water, which two solutions were mixed and then the precipitated hydroxides were prepared for adding sodium hydroxide. The co-precipitated powders were dried by the thermal drying at 8$0^{\circ}C$ for 24 h and by freeze drying at -4$0^{\circ}C$, 30 mtorr for 72 h. The lattice parameter and crystallite size as a function of calcination temperature was characterized by XRD analysis. The lattice parameter of YDC was decreased with addition amount of yttrium and was estimated as 5.401683 $\AA$ at $700^{\circ}C$. Crystallite size were calculated by XRD-LB method, and morphologies were confirmed with the observation of TEM and SEM. The freeze dried YDC powders had medium diameter of 17 nm with more uniform size distribution than the thermal dried YDC posers, which were mainly ascribed to the difference of agglomerates formation during drying stage.

• 한국식품영양학회지
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• 제12권3호
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• pp.258-264
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• 1999

This study was carried out to investigate the status in weight loss yield of edible meat quality and free amino acid contents of the snow crab(Chionoectes japonicus) by steaming and various drying treat-ment. Change of body weight loss in steaming treatment sample were 20.48∼26.72% and yield of edible meat of steaming sample was higher than raw sample(p<0.05) The pH value was increased with steam-ing and drying and pH of trunk meat was more increased than leg meat. Volatile basic nitrogen(VBN) content of vacuum dried sample was highest and VBN of hot-air and freezing dried sample were about 10mg%. Content of vaccum dried sample wre 41.33 and 48,56mg%. Thirty kind of free amino acids dectected in the snow crab and changes of free amino acid in leg meat were markedly reduced by vacuum drying and the reducing ratio of leg meat by freeze drying was little. The major free amino acid of leg and trunk meat were 39.94% 46.78% respectively. The formation of flavor free amino acid in freezing dried sample were high but its hot-air aried sample were small.

• Journal of the Korean Wood Science and Technology
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• 제36권2호
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• pp.20-28
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• 2008

This study was carried out to provide the so-called circumferential slicing method for investigating radial distributions of the tangential strains and of moisture contents within the log cross section (LC) of Kalopanax pictus during indoor drying it. While the heartwood showed an almost uniform moisture content distribution in the range of about 50~55% in case of the green wood, it has gradually decreased toward the outer side, showing about 19% of moisture content difference from the innermost slice. Although the moisture gradient along the radial direction has gradually become gentle as drying progresses, the sapwood of the outer side represented the moisture contents below the fiber saturation point after 24 hours of drying while the heartwood in the inner part showed the moisture contents higher than the fiber saturation point. The pith side was laid under the tensile stress after 24 hours of drying, and then gradually decreasing toward the bark side, and showed the distribution being switched again to the tensile stress on the bark side. As the drying has progressed, this trend got more intensified, and finally showed the U-shaped distribution model after 48 hours of drying. The circumferential slice test is considered to be suitable in quantitatively determining the tangential strains and moisture content within a LC.

• 한국가구학회지
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• 제27권1호
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• pp.43-48
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• 2016

PEG (Polyethylene glycol) impregnation in wood reduces the occurrence of checking during kiln drying. The volumetric shrinkages of wood PEG impregnated by pressure (PEG-P) or soaking (PEG-S) methods, and oven-dried by vent (VD) or air-tight (AD) methods were measured and compared with the controls. The average oven-dry weight of PEG impregnated specimens was larger than that of the controls by 3.6 g, but was not influenced by the drying methods. The average of the total volumetric shrinkage of PEG-P-VD specimens was the least (2.3%), while that of CON-S-AD specimens was the largest (28.9%). Within a drying method the total volumetric shrinkage of the control was the largest followed by PEG-S and PEG-P specimens, which implied that residual PEG in wood restrained its shrinkage during drying.

• Food Science and Biotechnology
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• 제15권4호
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• pp.506-510
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• 2006

To be used as a source of astaxanthin by animals, the red yeast Xanthophyllomyces dendrorhous needs to be dried and the cell wall ruptured. Spray-drying and flat-roller milling successfully prepared the yeast as a feed additive with little loss of astaxanthin. Spray-drying successfully dried the yeast with negligible decomposition of astaxanthin compared to drum-drying. By repeated milling with a flat-roller mill, astaxanthin extracted with ethanol increased from 0.01 to 1.31 mg astaxanthin/g yeast. This method did not decompose astaxanthin in contrast to chemical digestion of the cell wall. Flat-roller milling effectively flattened and cracked the dried cells. Astaxanthin in yeast prepared by spray-drying and flat-roller milling was well absorbed by animals. Specifically, when spray-dried and milled yeast was supplied in the feed (40 mg astaxanthin/kg feed), astaxanthin was successfully absorbed (1,500 ng/mL blood and 1,100 ng/g skin) by laying hens.

• Fisheries and Aquatic Sciences
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• 제24권1호
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• pp.19-31
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• 2021

Seaweeds are a potential source of minerals, essential amino acids, fatty acids, proteins, and various bioactive compounds such as antioxidants. The higher water content of seaweeds reduces the shelf life and this requires the appropriate drying method. The drying conditions play a major role in the conservation of nutrient composition in dried seaweeds. In recent years, the seaweed industry has used many different drying methods with advantages and limitations. Hybrid hot-water Goodle dryer (HHGD) which is a special dryer mixed with hot-water and a Korean traditional heating system (Goodlejang) might be a solution to avoid these limitations. The present study evaluated the effect of drying conditions in HHGD on nutrient composition and bioactivities of brown seaweeds. Moreover, freeze-dryer (FD) and HHGD were employed in this study to compare the dried outputs obtained from four brown seaweed species. The present study aims to evaluate the effect of the hybrid hot-water Goodle drying method (HHGDM) on the nutritional composition and antioxidant activity of dried seaweeds. AOAC standard methods were used to analyze the proximate composition of dried samples and their 70% ethanol extract. The intracellular and extracellular antioxidant activities were evaluated using Vero cells and electron spin resonance (ESR) spectrometer respectively. High performance liquid chromatography, apoptotic body formation, and in-vivo experiments were used for further confirmation of the quality of dried output. The proximate composition results obtained from drying in HHGD and FD did not exhibit any significant difference. Moreover, the seaweed extracts from the dried seaweeds by HHGD and FD dryings were also not different and both significantly down-regulated in-vivo and in-vitro oxidative stress. Furthermore, the high performance liquid chromatography results revealed that the two dryers did not make the major peaks different in the chromatograms. Freeze-drying method (FDM) provides elevated quality for dried output, but there are limitations such as high cost and low capacity. The results from a novel HHGD did not provide any significant difference with the results in FD and expressed a potential to avoid the limitations in FD. Overall, these findings solidified the applicability of HHGD over FD.

• Journal of the Korean Wood Science and Technology
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• 제17권3호
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• pp.67-81
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• 1989

This experiment was carried out to know the mothod of changing the step of moisture content schedule with time in conventional kiln drying. For the purpose of this object. we made drying model by applying the moisture diffusion model by J.FSiau(1984) to average moisture content equation by J.Crank(1956) derived it from Fick's second law. And to verify this method of drying model. 2.5cm-thick boards and 5.0cm-thick dimension lumbers of Pinus densiflora were kiln-dried with the schedule of T11-C3 and T10-C4, respectively. And then the drying rates were investigated and compared with those calculated from drying model. The results obtained were as follows 1. Average drying rate and total drying time of board to dry to 6.5% moisture content were 0.64%/hr and 109hr., and those of dimension lumber to dry to 8.3% moisture content were 0.4%/hr. and 162hr., respectively. 2. The moisture content of shell and core decreased by equalizing treatment and increased by conditioning treatment both on board and dimension lumber. But the moisture gradient was lower after conditioning than after equalizing. 3. As the drying was proceeded, the transverse bound water diffusion coefficient all but linearly decreased, the water vapor diffusion coefficient abruptly curvilinearly increased, while the transverse diffusion coefficient curvilinearly decreased both on board and dimension lumber. But each of diffusion coefficients on board was larger than that on dimension lumber. 4. Compared to experimential drying rate of board. theoretical drying rate was larger at 30.0%-21.8% moisture content range and was similiar at 21.8%-5.4% moisture content. And in case of dimension lumber, the drying rate was similiar at 30.0%-16.1% moisture content range but theoretical drying rate was much lower at 16.1%-8.3% moisture content range. 5. The possibility of adapting this drying model to changing the moisture content schedule step with time was in the range of 21.8%-5.4% moisture content on board. And in the case of dimension lumber that was in the range of 30.0%-16.1% moisture content.

• 한국약용작물학회지
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• 제25권2호
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• pp.89-94
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• 2017

Background: The purpose of improving the quality of oriental medicinal herbs is to contribute to the improvement of the income of farm. The present study investigated the effect of reasonable drying methods, different storage conditions and packageing materials on quality and stability of Scutellaria baicalensis Georgi and for developing GAP (good agricultural practice) guide book. Methods and Results: Three methods of drying Scutellaria baicalensis roots produced over two years were used to estimate loss rate owing to drying, storage, and packaging. The methods of drying were categorized into natural drying (36 - 60 h by sunshine), drying with heat dryer (2 - 10 h), or drying with gas bulk dryer (2 - 10 h). After cleaning, and initial drying for a few days under controlled temperature conditions, the second phase of drying was carried out at 35, 45 and $55^{\circ}C$. Changes in hunter color values and quality under the two studied storage treatments (at $20^{\circ}C$ indoors and at $4^{\circ}C$ in a refigerator) were evaluated. Storage period for 60, 120, and 180 days in three packaging materials, PE (polyethylene package), PP (polypropylene gunnysack), and WP (watertight packing paper) were studied. Conclusions: Initial cleaning, reasonable gas drying and hot air drying, and drying in an oven at 35 and $45^{\circ}C$ after cutting the roots resulted in the lowest loss rates in S. Baicalensis root. Hunter color valuse indicated that stroage of dry roots at room temperature was better than PP packaging, and that cold stroage was better than PE packaging for long-term stability.

• 한국식품영양학회지
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• 제30권3호
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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.

• 한국산학기술학회논문지
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• 제22권2호
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• pp.401-408
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• 2021

에너지 분권 및 신재생에너지 정책에 따라 연료용 목재칩 보급도 증가하고 있는 추세이다. 본 연구는 연료용 목재칩(Wood chip)을 이용하여 농촌지역에 난방에너지를 공급하는데 필요한 기술적 방법을 제시하는데 목적이 있다. 따라서 본 연구에서는 10톤의 목재칩을 적재할 수 있는 간이 자연환기건조장을 설치하여 8개월 동안 자연건조의 효과를 파악하고 이를 바탕으로 연료용 목재칩 품질기준을 충족하기 위한 자연건조 방법을 도출하고자 하였다. 연구결과 농촌지역에서 쉽게 조달할 수 있는 재료로 자연환기건조장을 갖춘다면 약 90일간의 건조 기간을 거쳐 함수율 20% 이하의 고품질 연료용 목재칩을 생산할 수 있음을 확인하였다. 또한 규격에 부합하는 흡기 및 배기 시스템을 갖출 경우 목재칩 품질에 영향을 주는 곰팡이의 번식과 발효의 효과적인 차단이 가능하였다. 이와 같은 연구결과는 고비용 강제건조 설비를 도입하지 않더라도 농촌지역의 여건에 부합하는 저비용의 자연건조시스템을 통해서도 품질기준을 충족하는 양질의 목재칩 생산이 가능함을 증명한다. 따라서 미이용 산림바이오매스를 활용한 연료용 목재칩 자연건조기술 개발사업, 농촌보급용 소규모 자연건조장의 성능 및 설계기준 등과 관련한 정책수립이 요구된다.