Microwave treatment to optimize physicochemical properties of modified Busil (Xanthosoma sagittifolium) starch

Abstract

COVID-19 pandemic encourages the utilization of local food sources to ensure food availability. Busil (Xanthosoma sagittifolium) was readily available and affordable in Banjarnegara Regency in the Province of Central Java in Indonesia. However, the busil starch utilization was still rare due to the low functional properties of the native busil starch. The objective of this study was to explore busil starch physicochemical characterization enhancement after microwave irradiation treatment, especially on the stability of heat processing. This research was conducted in two steps. First, microwave treatment (with a variation of energy and irradiation time) of native busil starch (NBS), and the second was modified busil starch (MBS) physicochemical characterization. A rise in amylose was observed on MBS. SEM analysis was shown MBS granules are breakdown. Through viscosity, final viscosity, setback viscosity, peak time, and the pasting temperature of MBS generally were increased. Meanwhile, peak viscosity and breakdown viscosity of MBS was decreased. Thermal properties of MBS like onset (To), peak (Tp), and conclusion (Tc) temperatures were also increased. The degree of whiteness index (DW) of MBS was decreased. FTIR analysis has shown that microwave treatment did not cause functional group alteration. XRD analysis has also demonstrated no change in the diffraction pattern but a slight change in the crystallinity index. Generally, microwave treatment leads to MBS thermal stability and potentially broaden MBS utilization on food processing product.