Impact of microwave irradiation on chemically modified talipot starches: A characterization study on heterogeneous...

In this study, the effect of chemical modifications such as oxidation, esterification and crosslinking was investigated alone and in combination with microwave irradiation on a non-conventional starch with 76% starch yield acquired from the trunk of matured talipot palm. The single- and dual-modifications imparted significant changes in the morphological, crystalline, pasting and rheological properties and digestibility of talipot starch. Characteristic peaks were observed in single- and dual-oxidized, esterified and crosslinked starches indicating their respective functional groups. All modifications significantly decreased (p ≤ 0.05) the relative crystallinity (RC) of talipot starches except for crosslinking, and the least RC (11.33%) was observed in microwave irradiated esterified starch. Microwave irradiation prior to chemical modifications showed a significant impact in the swelling and solubility of talipot starches. The decreased setback viscosity and increased light transmittance in single- and dual-microwave irradiated talipot starches showed their lowered retrogradation tendency, suitable for frozen foods. The resistant starch (RS) content was majorly improved in all heterogeneously dual modified talipot starches by incorporating more functional groups owed to structural and crystalline destruction in starch granules upon microwave irradiation. The highest RS content (45.02%) was observed in microwave irradiated esterified uncooked talipot starch.