• Food Engineering Progress
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• v.21 no.1
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• pp.42-48
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• 2017

The purpose of this study was to verify the drying characteristics of steamed sweet potato and to establish optimal drying conditions for far-infrared drying of steamed sweet potato. 4 kg of steamed sweet potato was sliced to thicknesses of 8 and 10 mm, and dried by a far-infrared dryer until a final moisture content of $25{\pm}0.5%$. The far-infrared dryer conditions were an air velocity of 0.6, 0.8 m/s and drying temperature of 60, 70, and $80^{\circ}C$. The results can be summarized as follows. The drying time tended to be reduced as temperature and air velocity for drying increased. The Lewis and Modified Wang and Singh models were found to be suitable for drying of steamed sweet potato by a far-infrared dryer. The color difference was 35.09 on the following conditions: Thickness of 8 mm, temperature of $80^{\circ}C$, and air velocity of 0.8 m/s. The highest sugar content ($59.11^{\circ}Brix$) was observed on the conditions of a thickness of 8 mm, temperature of 80, and air velocity of 0.8 m/s. Energy consumption decreased on the conditions of higher temperature, slower air velocity, and thinner steamed sweet potato.

• Journal of The Korean Society of Grassland and Forage Science
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• v.42 no.2
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• pp.73-78
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• 2022

This experiment was conducted to establish the technology for artificial hay preparation in Korea. Using far-infrared heater, a device that can control temperature, airflow, and far-infrared radiation was produced and conducted on the fourth harvested alfalfa. The drying conditions were carried out by selecting a total of four conditions. For each condition, the radiation rate was set to around 40% (33-42%), and the temperature was set at 58~65℃, and the speed of the airflow was fixed at 60m/s. The overall drying time was set to 30 min in the single and 60 min (30-30 min) and 90 min (30-30-30 min) in the complex condition, and the radiation rate and temperature were changed by time period. In the case of drying condition 1, the final dry matter (DM) content was 46.26%, which did not reach a DM suitable for hay. However, all of the alfalfa corresponding to the remaining drying conditions 2 to 7 showed a DM content of 80% or more, resulting in optimal alfalfa hay production. In power consumption according to the drying conditions, the second drying condition showed the lowest at 4.7 KW, and the remaining drying conditions were as high as 6.5 to 7.1 KW. The crude protein content was found to be high at an average of 25.91% and it showed the highest content in the 5th drying condition (26.93%) and the lowest value in the 6th drying condition (25.16%). The digestibility showed a high value with an average of 84.90%, and there was no significant difference among treatments (p>0.05). Considering the above results, it was judged that drying condition 2 was the most advantageous.

• Journal of Bio-Environment Control
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• v.31 no.4
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• pp.416-422
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• 2022

This study was conducted to investigate the effect of each light intensity and photoperiod combination on the growth and glucosinolates (GSLs) content of three species of Brassicaceae plants under the same daily light integral (DLI) conditions. Seeds of leaf mustard (Brassica juncea (L.) Czern.), red mustard(Brassica juncea L.) and kale (Brassica oleracea L. var. acephala (DC.) Alef.) were sown in a rockwool cubes and grown for three weeks. DLI was set to 10 mol·m^-2·d^-1 and treated with 10h-280, 14h-200, 18h-155, 22h-127 µmol·m^-2·s^-1 for three weeks. As a result at 14h-200 µmol·m^-2·s^-1 treatment, shoot fresh/dry weight, the number of leaves, and leaf area were increased in leaf mustard and kale but there was no significant difference in other treatments. In the total GSLs content, the treatment of 14h-200 µmol·m^-2·s^-1 increased significantly 139.95, 135.87, 154.03% compared to 10h-280, 18h-155, 22h-127 µmol·m^-2·s^-1 treatment in red mustard, and 14h-200 µmol·m^-2·s^-1 treatment increased significantly 132.96, 132.96, 134.03% compared to other treatments in kale. In red mustard, the treatment of 18h-155 µmol·m^-2·s^-1 showed an increase in shoot fresh/dry weight and the total GSLs contents than other photoperiods and 14h-200 µmol·m^-2·s^-1 treatment, the number of leaves significantly 15.62, 12.12, and 32.14% higher than other photoperiods. Since the DLI response is different depending on species even for similar Brassicaceae crops, it is necessary to get more detailed results by conducting optical light quality studies and deriving optimal DLI conditions to achieve minimum power consumption and maximum efficiency.