• Korean Journal of Food Science and Technology
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• v.31 no.3
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• pp.619-624
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• 1999

This work was to study the potential health food use of germinated colored rice after germinating and drying using microwave under vacuum. Colored rice was soaked in water at $15^{\circ}C$ for 2 days and then germinated at $25^{\circ}C$ for $3{\sim}4\;days$. The germinated colored rice was dried by different drying methods: microwave vacuum drying 1, microwave vacuum drying $2\;(drying{\rightarrow}crushing{\rightarrow}drying)$, hot air drying, vacuum drying and freeze drying. Each drier except freeze drier was set to maintain the sample temperature at $60^{\circ}C$. During microwave vacuum drying 1 or 2, the sample reached $60^{\circ}C$ much faster (within 5 min) and was dried much faster ($2{\sim}3\;hrs$ than the other drying methods. The initial drying rate of microwave vacuum drying was ten times faster than that of hot air drying. The microwave vacuum drying 2 retained the highest ${\alpha}-amylase$ activity, followed by microwave vacuum drying 1, freeze drying, vacuum drying, and hot air drying.

• Korean Journal of Food Science and Technology
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• v.25 no.5
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• pp.558-564
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• 1993

The drying characteristics of fluidized bed drying with different drying conditions using naked barley were carried out. This fluidized drying mechanism of naked barley was consisted of consecutive two falling rate parts, first falling rate period and second falling rate period without showing constant rate period. The drying rate constant was increased with decreasing charged amount and relative humidity and increasing air temperature and air velocity. Since the drying rate constant expressed by Arrhenius type equation in the falling rate period showed good linearity, the falling rate period was considered as the controlling step. The activation energy of first falling step was 1,900 cal/gmol, while for second falling step the values showed 2,500 cal/gmol.

• Korean Journal of Food Science and Technology
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• v.27 no.3
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• pp.358-364
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• 1995

In order to determine the moisture content level for safe storage of wild vegetables, drying characteristics and water vapor sorption characteristics of four vegetables, i.e., zucchini slice, sweet potato stem, taro stem, and platycodon, were investigated. The drying curves of these vegetables were consisted of three characteristic stages which were the initial settling down period, the constant drying rate period, and the falling drying rate period. And the falling rate period of the vegetables showed 2 or 3 parts of falling rate. All of the falling rate curves of the vegetables showed upwardly convex shape which is known as a characteristic pattern for the drying of fibrous food materials. The critical moisture contents of the vegetables were $8.29{\sim}9.75,\;10.40{\sim}15.08,\;9.51{\sim}14.52\;and\;3.29{\sim}3.56g\;H_2O/g$ dry solids for zucchini slice, sweet potato stem, taro stem, and platycodon, respectively. Activation energy values of drying rate during falling rate period were 2.30, 2.11, 4.97, and 2.80 kcal/mol for zucchini slice, sweet potato stem, taro stem, and platycodon respectively. The BET monolayer moisture contents of the vegetables were $10.05{\sim}13.59,\;9.49{\sim}12.69,\;9.50{\sim}16.48\;and\;5.01{\sim}5.44g\;H_2O/g$ dry solids for zucchini slice, sweet potato stem, taro stem, and platycodon, respectively. And these values were found to be very compatible with the values of the critical moisture content. Consequently, it was found that the moisture of these vegetables should be removed below the BET monolayer moisture content or below the critical moisture content for the long term storage.

• Korean Journal of Food Science and Technology
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• v.33 no.6
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• pp.706-713
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• 2001

The influencing factor in drying characteristics of fluidized bed drying with different drying conditions for husked barley were carried out. This fluidized drying mechanism of husked barley was consisted of consecutive two falling rate parts, first falling rate period and second falling rate period without showing constant rate period. The drying rate constant was increased with decreasing charged amount and relative humidity and increasing air temperature and air velocity. Since the drying rate constant expressed by Arrhenius type equation in the falling rate period showed good linearity, the falling rate period was condsidered as the controlling step. The activation energy of first falling step was 1,100 cal/gmol, while for second falling step the values showed 1,600 cal/gmol.

• Korean Journal of Food Science and Technology
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• v.11 no.4
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• pp.264-272
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• 1979

The flat-plate and tubular soar collectors were designed and constructed for drying the rough rice, and the performance of the collectors and drying effect were investigated when rough rice was packed in grain bin connected to collectors. Average-monthly radiation on a horizontal surface based on bright sunshine in Daejeon area during 1978 was the highest as $16,814\;KJ/m^2{\cdot}day$ in May and the lowest as $4,254\;KJ/m^2{\cdot}day$ in December, and significane was not recognized between the calculated and recorded values. The thermal effciency of collectors were increased as radiation increased during drying period and the average thermal effciency of flat-plate and tubular collectors in 11 to 12 o'clock a.m were 28.12 and 16.75%, respectively. The average inlet temperature of grain bin at 12 o'clock was shown as 20.02 at control 40.5 at grain bin connected to tubular collector and $55.1^{\circ}C$ at grain bin connected to flat-plate collector. In 25 cm rough rice depth in grain bin, tim taken for drying from initial moisture content at 27.4 to decrease upto 17.0% (14.5 % on wet basis) were 32 in control, 18 in grain bin connected to tubular collector and 11 hrs to flat-plate collector, and grain depth influenced drying rate remarkably. In the view point of drying characteristics, drying pattern showed initially falling-rate to constant-rate period finally.