Fluidization‐bed drying and microwave radiation effects on drying rate, fatty acid, protein, and germination of flaxseed

Flaxseeds are known for their invaluable omega‐3 fatty acids and proteins. Flaxseeds need to be dried to 10%w.b. moisture for safe long‐term storability. Traditional drying ruptures the nutritional properties, therefore, this study analyzed the effect of fluidized‐bed and microwave drying on the fatty acid and protein constituency of flaxseed. The drying air temperatures in the fluidized‐bed drying tests were 40, 50 and 60°C. Three microwave power densities were selected 0.3, 0.6 and 1 W g−1. Results showed a minor effect on fatty acids whereas a significant effect on protein content with both the drying methods. A protein reduction of 7, 21, and 23% was observed for drying air temperatures of 40, 50, and 60°C, respectively. For the microwave tests, 39, 58, and 63% protein reductions for 0.3, 0.6 and 1 W g−1 power densities were observed, respectively. The fatty acids showed a maximum increase of 0.85% for fluidized bed drying and 1.23% for microwave. Practical applications This study contributes a step‐forward knowledge toward adoption of microwave technology in flaxseed oil extraction industry. Previous pilot‐scale studies solely on microwave utilization have shown limited scale‐up due to its high infrastructure cost associated with emitting high‐power densities. However, if explored with a combination approach along with fluidized bed (40°C at 0.3 W g−1) to assist in early removal of surface moisture from flaxseed, it could be a potential platform to increase the productivity in parallel to matching the associated overall cost. A proper cost analysis could be a future aspect of this study. The effect of fluidized bed drying at air temperatures of 40, 50, and 60°C as well as the effect of microwave drying at power densities of 0.3, 0.6, and 1 W g−1, on drying rate, fatty acid content, protein content, and germination rate of flaxseed was studied.