Microwave drying of banana blossoms (Musa acuminata): Mathematical modeling and drying energetics

摘要

This research work explored the effect of microwave output power on drying characteristics, moisture diffusion, drying efficiency, and specific energy consumption. Banana blossoms was cut into 3 mm thickness and was dried as monolayers at five different power levels (160, 320, 480, 640, and 800 W). After drying, the powdered banana sample was analyzed for color attributes and functional characterization. Eight different mathematical models were investigated and the Page model was the best-fitted model for all samples with the maximum R~2 values of 0.99359 (P-160 W), 0.99505 (P-320 W), 0.99344 (P-480 W), 0.99160 (P-640 W), and 0.99192 (P-800 W). The drying time was minimizing from 40 to 10 min as the microwave output powers increase from 160 to 800 W. The drying constant (k) is enhanced as microwave power increases. The effective diffusivity of banana blossoms varied from 4.428 × 10~(−7) to 1.171 × 10~(−7) m~2/s and the activation energy was estimated as 7.96 W/g. Maximum energy consumption was found to be 7.74 MJ/kg water at 160 W, whereas minimum energy consumption was minimum (5.74 MJ/kg water) at a microwave power of 640 W. Energy efficiency increases with increasing microwave output power. Applied microwave output power was a critical aspect of all color parameters of the banana blossoms powder. Powdered banana blossoms dried at 640 W showed the highest lightness L* of 54.43 ± 0.46 with redness (a*) of 4.19 ± 0.03, and yellowness (b) of 10.71 ± 0.29. The highest water solubility index was 53.30 ± 0.59 % for the sample dried at 640 W and oil absorption capacity (g/g) and foaming capacity (ml) were varied from 1.76 ± 0.07 to 2.93 g/g and 1.67 ± 0.58 to 4.53 ± 0.57 ml.