Document Type : Research Article
Authors
1
MSc Student, Department of Food Science and Technology, Faculty of Food Industry, Bu-Ali Sina University, Hamedan, Iran
2
Associate Professor, Department of Food Science and Technology, Faculty of Food Industry, Bu-Ali Sina University, Hamedan, Iran.
Abstract
This study investigated the effects of various drying methods including convective, infrared, and microwave drying on the moisture content, pH, acidity, color indices, total phenolic content (TPC), and antioxidant capacity (AC) of sprouted quinoa powder. Initially, the quinoa seeds were soaked in magnetized water for 1 h. Then the quinoa seeds were incubated in a magnetic field at 25°C for 72 h for sprouting. To increase the phenolic compounds of the powders, the sprouts were treated by ultrasound for 5 min. The sprouts were dried in three ways and the powder prepared from them was analyzed. The infrared radiation facilitated removal of moisture from the quinoa sprouts, increased the effective moisture diffusivity coefficient, and shortened the dehydration duration. The moisture content and pH of the sprouted quinoa powders were in the range of 2.61 % to 7.03 %, and 5.95 to 6.08, respectively. The acidity of convective, infrared, and microwave dried sprouted quinoa powders was 1.24 %, 1.19 %, and 0.81 %, respectively. Among the sprouted quinoa powders, the sample dried using microwave treatment exhibited the lowest lightness value (67.78) and the highest redness (9.89) and yellowness (21.09) indices. The infrared-dried powders had the maximum TPC and AC. The TPC of convective, infrared, and microwave dried powders were 916.98, 1268.48, and 1262.46 μg gallic acid/g dry, respectively. In summary, using infrared was chosen as the best way to dry quinoa sprouts because it dries them faster, keeps the right color parameters, and results in the highest levels of beneficial compounds.
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