Vacuum microwave drying (VMD) of strawberries was done using a
custom made, Airmax lab-scale microwave vacuum dryer (700 W,
2450 MHz) (Bórquez et al., 2010). In the cavity of the microwave
oven, three static horizontally stapled acrylic trays (width: 10–13 cm;
length: 17 cm) covered with adsorbent paper and supported by rear
and front acrylic disks (diameter: 14 cm) were used to distribute a
sample ofmaximum250 g of strawberries. Individual berries were separated
1 cm from each other to allow individual drying. Trays were
completely covered by a vertical cylindrical container (diameter:
18 cm; length: 24 cm; thickness: 6 mm) made of black polyethylene,
which allows passage of microwaves. This container was adjusted to a
circular slot at the rear side of the oven for hermetical sealing during operation,
where sub-atmospheric pressure was provided by a vacuum
pump. Condenser with refrigeration liquid (−10 °C) and condensate
trap were connected in-line with the vacuum hose to remove moisture
from sub-atmospheric air before reaching the vacuum pump. Absolute
pressure was controlled by a manometer and maintained in the range
of 10 to 70 mm Hg by the vacuum pump and a vent for air inlet. Four
probes of optical fiber (model TMI4, FISO Technologies Inc., Canada)
for temperature measurement were inserted in the center of different
berries. The vacuum microwave drying system operated for 3 h at a
temperature of 50 ± 1 °C, removing the excess of microwave heat by
recirculation of cold water between two polypropylene containers outside
the vacuum chamber and by using an on–off temperature control
system for the magnetron after the first 20 min after starting each experiment.
Then the microwave control system was switched off, but
the vacuum drying conditions were maintained for one extra hour.
Vacuum microwave drying (VMD) of strawberries was done using a
custom made, Airmax lab-scale microwave vacuum dryer (700 W,
2450 MHz) (Bórquez et al., 2010). In the cavity of the microwave
oven, three static horizontally stapled acrylic trays (width: 10–13 cm;
length: 17 cm) covered with adsorbent paper and supported by rear
and front acrylic disks (diameter: 14 cm) were used to distribute a
sample ofmaximum250 g of strawberries. Individual berries were separated
1 cm from each other to allow individual drying. Trays were
completely covered by a vertical cylindrical container (diameter:
18 cm; length: 24 cm; thickness: 6 mm) made of black polyethylene,
which allows passage of microwaves. This container was adjusted to a
circular slot at the rear side of the oven for hermetical sealing during operation,
where sub-atmospheric pressure was provided by a vacuum
pump. Condenser with refrigeration liquid (−10 °C) and condensate
trap were connected in-line with the vacuum hose to remove moisture
from sub-atmospheric air before reaching the vacuum pump. Absolute
pressure was controlled by a manometer and maintained in the range
of 10 to 70 mm Hg by the vacuum pump and a vent for air inlet. Four
probes of optical fiber (model TMI4, FISO Technologies Inc., Canada)
for temperature measurement were inserted in the center of different
berries. The vacuum microwave drying system operated for 3 h at a
temperature of 50 ± 1 °C, removing the excess of microwave heat by
recirculation of cold water between two polypropylene containers outside
the vacuum chamber and by using an on–off temperature control
system for the magnetron after the first 20 min after starting each experiment.
Then the microwave control system was switched off, but
the vacuum drying conditions were maintained for one extra hour.
การแปล กรุณารอสักครู่..
Vacuum microwave drying (VMD) of strawberries was done using a
custom made, Airmax lab-scale microwave vacuum dryer (700 W,
2450 MHz) (Bórquez et al., 2010). In the cavity of the microwave
oven, three static horizontally stapled acrylic trays (width: 10–13 cm;
length: 17 cm) covered with adsorbent paper and supported by rear
and front acrylic disks (diameter: 14 cm) were used to distribute a
sample ofmaximum250 g of strawberries. Individual berries were separated
1 cm from each other to allow individual drying. Trays were
completely covered by a vertical cylindrical container (diameter:
18 cm; length: 24 cm; thickness: 6 mm) made of black polyethylene,
which allows passage of microwaves. This container was adjusted to a
วงกลมช่องเสียบที่ด้านหลังของเตาปิดแน่นปิดการดำเนินการ
ที่ความดันย่อยโดยปั๊มสุญญากาศ
. คอนเดนเซอร์กับเครื่องทำความเย็นเหลว ( − 10 ° C ) และสายเชื่อมต่อกับดัก
สอดคล้องกับสูญญากาศท่อเพื่อเอาความชื้นจากอากาศบรรยากาศ
ย่อยก่อนถึงปั๊มสูญญากาศ . แน่นอน
ถูกควบคุมโดยเครื่องวัดความดัน และเก็บรักษาในช่วง 10 ถึง 70 มม. ปรอท
โดยปั๊มสุญญากาศและระบายอากาศท่อ . 4
) ของเส้นใยแสง ( แบบ tmi4 fiso Technologies Inc , แคนาดา )
สำหรับการวัดอุณหภูมิอยู่ที่แทรกอยู่ในศูนย์ของผลเบอร์รี่ที่แตกต่าง
ไมโครเวฟระบบสุญญากาศการ 3 ชั่วโมง ที่อุณหภูมิ 50 ±
1 ° Cขจัดส่วนเกินของเตาอบไมโครเวฟ โดยการหมุนเวียนของน้ำที่เย็นระหว่างสอง
นอกโพรพิลีนภาชนะสูญญากาศและใช้ในระบบการควบคุมอุณหภูมิสำหรับออก
สำหรับตรอนหลังจาก 20 นาทีหลังจากเริ่มการทดลองแต่ละ .
แล้วระบบไมโครเวฟถูกปิด แต่
เงื่อนไขการรักษาสำหรับเครื่องดูดฝุ่นแห้งหนึ่งชั่วโมงพิเศษ
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