Influence of hot-air drying and freeze-drying on functional, rheological, structural and dielectric properties of green banana flour and dispersions

Abstract The green banana flour (GBF) is a rich source of resistant starch, minerals, and phytochemicals and can be used as a functional ingredient for food product development. Two types of drying, namely, freeze-drying (FD) and hot-air tray drying (TD) were employed for the production of GBF, and thereafter, the resultant flour quality was compared by measuring physicochemical, functional, structural, dielectric and rheological properties. The structural and rheological properties of flour samples were examined by using scanning electron microscopy, X-Ray Diffractometer, rheometer, and visco-amylograph. Both the TD and the FD affect the particle size, color, starch, resistant starch, and water hydration properties of GBF significantly. During thermal scanning, the peak gelatinization temperature (Tp) (82.5–83.4 °C) and the starch-lipid melting transitions (102.4–109.2 °C) were detected for both samples. The flour in dispersion (F/W = 1:3) showed the solid-like behavior (G′>G″) and the mechanical rigidity influenced by the drying methods (P