Ultrasonic assisted enzymolysis based modification of native banana starch - A comprehensive analyses of the structural, morphological, rheological and textural properties

Native banana starch (NS) has few limitations, such as poor solubility, low resistance to shear, temperature, and inconsistent retrogradation. This study investigates the effects of mono (α-amylase, pullulunase) and sequential enzymatic modifications of NS along with the application of ultrasound to enhance its functional attributes. Starch modified with α-amylase alone and along with ultrasound resulted the lowest amylose (20.23 %), resistant starch (28.22 %), higher rapidly digestible starch (48.92 %). Whereas pullulanase modification resulted in higher amylose (38.14 %), resistant starch (52.72 %) and therefore the better swelling power and water holding capacity. The retrogradation negatively associated with the solubility of these modified starches is outlined through the static viscosity measurements. Ultrasound enhanced the efficiency of enzymes by altering the structure of starch granules, confirmed through SEM analysis and provided differentiated thermal stability as observed through viscosity and enthalpy values from DSC. The dual sequential enzymatic treatment with ultrasound also significantly improved the starch solubility by altering the structure as evidenced through XRD and FTIR analysis. NMR ¹H spectra revealed distinct variations in the anomeric peaks and hydroxyl regions of modified starches. Cluster analysis highlighted the unique characteristics of ultrasound-assisted starches.