• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.16 no.2
• /
• pp.167-174
• /
• 2004

A sorption cool pad brings cooling effect without any pre-cooling, nor any external energy supply. It uses evaporative cooling effect stimulated by the desiccative sorption. In this paper, heat and mass transfer in the sorption cool pad are investigated theoretically. The evaporative cooling process caused by the desiccant is modeled and analyzed considering the sorption characteristics of the desiccant. Two nondimensional parameters are found to dominate the cooling process： one is related to the psychrometric characteristics and the other is to the sorption capacity of the desiccant. The former decides the time to reach the lowest temperature and the later controls the time duration of the cooling effect being sustained.

• Journal of the East Asian Society of Dietary Life
• /
• v.11 no.6
• /
• pp.479-484
• /
• 2001

The absorption characteristics of persimmon powder related to different drying methods and various storage temperatures was investigated. The physical properties of persimmon powder by different drying methods displayed the largest amount of porosity in the freeze-dried sample, and the smallest in hot air dried sample. Equilibrium moisture was reached in 6 days. Monolayer moisture contents were predicted to 0.09687~0.19712(freeze drying), 0.07820~0.18617(vacuum drying) and 0.07715~0.18056(hot air drying) g H2O/g solid respectively using the BET equation. BET equation for isothermal absorption curve showed over 0.95 R-square for all dried methods. Monolayer moisture contents were increased as storage temperature was incremented because water molecular movement was more active and there was a greater chance to clash with the absorption surface area.

• Korean Journal of Food Science and Technology
• /
• v.31 no.6
• /
• pp.1557-1562
• /
• 1999

As a series of studies on the preservation methods for boiled-dried anchovies, determination of sorption properties and shelf-life prediction were made for the samples. Dried anchovies, which were gamma-irradiated at pre-established dose (5 kGy) after packaging in both a polyethylene film (PE, 0.1 mm) and a laminated film $(nylon\;15\;{\mu}m/polyethylene\;100\;{\mu}m,\;NY/PE)$, were subjected to a quality evaluation during 4 months at different storage conditions, such as $15^{\circ}C/68%\;RH,\;25{\circ}C/75%\;RH,\;and\;35^{\circ}C/84%$ RH. The sample showed 5.47% of BET monomolecular layer moisture content and the corresponding water activity, 0.15. The velocity constants of browning reaction and organoleptic changes in the sample were in proportion to storage temperature, and $Q_{10}$, values were ranged from 2.17 to 2.40 in a given packaging and irradiation conditions. In the shelf-life prediction of the stored sample at $25^{\circ}C$, non-irradiated groups packaged in PE and NY/PE were 84 days and 125 days. While 5 kGy-irradiated groups in the same packaging were 126 days and 138 days, respectively. This finding proved the efficacy of laminated-film packaging and irradiation treatment in preserving the quality of dried anchovies.

• Journal of Life Science
• /
• v.10 no.3
• /
• pp.229-235
• /
• 2000

The absorption characteristics of Korean yam powder according to different drying methods were investigated. The physical properties of yam powder by different drying methods were showed the biggest porosity in freeze drying sample, while the smallest in hot air drying sample. No difference was founded in proximate compositions of yam powder by various drying methods. The amount of total phenolic compound and Vit C were showed the bigger decrement in freeze dried sample than other drying methods. The time reaching to equilibrium moisture content were determined in 12 days. Monolayer moisture contents were predicted to 0.0508∼0.0588 by BET equation and 0.0705∼0.0811 g H2O/g solid by GAB equation. BET equation for isothermal absorption curve showed over 0.95 R-square for every drying methods. GAB equation showed over 0.99 in vacuum and freeze drying but a poor R-square in hot air drying.

• Journal of Applied Biological Chemistry
• /
• v.51 no.6
• /
• pp.277-284
• /
• 2008

The objective of this study was to investigate the effect of soaking time on physicochemical properties of waxy rice, waxy rice flour and waxy rice starch. Waxy rice (WR), waxy rice flour (WRF), waxy rice starch (WRS) were soaked at $18^{\circ}C$ for 14 days and dried at $40^{\circ}C$. Dried samples were grounded and sieved using 180 mesh. Physicochemical properties of the three samples, such as swelling power, solubility, moisture sorption isotherms and pasting properties using rapid visco analyzer (RVA) and crystal pattern using X-ray diffractometer were determined. In all samples, soaking time greatly influenced moisture sorption isotherms but no typical pattern was shown. Swelling power was not greatly changed by soaking time in the three samples. Solubility increased with increasing soaking time in all three samples, indicating that some soluble particles were exuded during soaking. In RVA pasting properties, WR and WRF showed a similar pattern, while WRS showed different pasting properties, suggesting that rice protein plays a significant role in pasting properties. X-ray diffraction patterns of all three samples showed typical A-type crystal pattern suggesting that soaking did not affect crystalline region of samples.