Investigation of morphological, structural, and thermal changes in palmyra starch (Borassus flabellifer) induced by ultrasonication and alcohol-alkali treatment

This study investigates the modification of non-conventional palmyra starch through ultrasonication and alcohol-alkali treatments, assessing their effects on structural, morphological, thermal, and functional properties of native palmyra starch, and comparing them to commercial cassava starch. The results indicate that native palmyra starch shares similar characteristics with cassava starch, including amylose content, granule morphology, crystalline structure, and thermal properties. Modifications significantly altered the whiteness ( L *) value, and amylose content; with ultrasonication achieving the highest amylose content of 32.38 %. A decrease in crystallinity from 25.32 % to 19.12 % was observed, alongside an increase in solubility (11.06–21.56 g/g) and swelling power (14.90–17.69 g/g). The modified palmyra starch exhibited an A-type crystalline structure with diffraction peaks at 2 θ = 15.1°, 17.1°, 18.0° and 23.0°, which remained uniform with the native starch. FTIR analysis revealed no significant changes in characteristic peaks after ultrasonication and alcohol-alkali treatments. The modifications also resulted in reduced in gelatinization enthalpy (7.98–6.68 J/g), compared to native palmyra starch (12.61 J/g). Overall, the modified palmyra starch demonstrated promising properties, suggesting its potential for a wide range of applications in both food and non-food industries. • The non-conventional palmyra starch-modified using ultrasonication and alcohol-alkali treatments. • The sequence of modification was altered to see its effect on starch properties. • Modified palmyra starch exhibited a reduction in crystalline region. • Increased solubility and swelling power values of modified palmyra starches.