Effect of Ultrasound as a Pretreatment on the Extraction Yield, Physicochemical, Functional, Thermal, Structural, Morphological Properties and In Vitro Digestibility of Bathua ( Chenopodium album ) Starch

Abstract

The present study explored the effect of probe ultrasound (US) as a pretreatment technique on the extraction efficacy of bathua starch (BS). US was performed at varying power levels of 200, 350, and 500 W for 10, 20, and 30 min. The extracted BS was analyzed for techno‐functional properties, pasting characteristics, morphology, and X‐ray diffraction (XRD) studies. At 350 W‐30 min, US significantly ( p < 0.05) increased the starch yield (49.91%), paste clarity (13.72%), solubility (11.13%), water absorption capacity (1.97 g/g), oil absorption capacity (2.41 g/g), and emulsifying capacity (57.54%) as compared to the control starch. The field emission gun scanning electron microscopy revealed the presence of cracks and pores on the surface of the starch granules. In comparison to the control sample, the FTIR spectra and X‐ray diffractograms of starch extracted at 350 W‐30 min showed a small decrease in peak intensity with considerably ( p < 0.05) reduced relative crystallinity and significant ( p  < 0.05) reduction in pasting temperature, peak, setback, breakdown, and final viscosity. Additionally, US pretreatment at 350 W‐30 min raised the amount of resistant and slowly digestible starch as compared to the control. According to multivariate analysis, the present study found the US pretreatment at 350 W‐30 min to be suitable for enhanced starch yield with improved techno‐functional properties of the BS.