Blackberry drying with various pretreatments of thermal, pulsed, chemical and mechanical using convective -infrared combined method
In this research was investigated the impact of various pre-treatments on effective moisture diffusivity coefficient (Deff</sub></em>), specific energy consumption (SEC</em>), total color difference and shrinkage of blackberry (Rubus spp) in convective – infrared dryer. Experiments were done at three temperature leveles 50, 60, 70 °C with four different pretreatments, including of blanching thermal pretreatment at 70, 80, 90 °C, pulsed pretreatment with microwaves power 90, 180, 360 W, chemical with Ascorbic acid solution at concentration of 1% and mechanical pretreatment with ultrasound in times of 15, 30, 45 min. Results shown that the highest and lowest of Deff</sub></em> value (1.43×10-8</sup> m²/s) and amount (55.52 kWh/kg) was obtained using microwave pretreatment under 360 W power and 70 o</sup>C drying temperature, respectively. Also, the minimum and maximum extent of Deff</sub></em> (4.24×10-9</sup> m²/s) and (239.89 kWh/kg) were in controlled sample and drying temperature of 50 °C, respectively. The highest amount of color difference (30.28) and shrinkage (55.62%) were seen in controlled sample. The lowest value of color difference (7.01) and shrinkage (19.23%) was obtained in microwave pretreatment with power of 360 W and drying temperature of 70 o</sup>C. So, the value of SEC (76.86%), color difference (76.85%) and shrinkage (65.43%) of samples reduced significantly (P<0.05) using various pretreatments, respectively.
- حق عضویت دریافتی صرف حمایت از نشریات عضو و نگهداری، تکمیل و توسعه مگیران میشود.
- پرداخت حق اشتراک و دانلود مقالات اجازه بازنشر آن در سایر رسانههای چاپی و دیجیتال را به کاربر نمیدهد.