Reactive Extrusion-Assisted Process to Obtain Starch Hydrogels through Reaction with Organic Acids

A totally green process based on reactive extrusion was used for the production of cassava starch hydrogels through reaction with two organic crosslinking agents, citric (CA) and tartaric (TA) acids. CA TA were at different concentrations (0, 2.5, 5.0, 10.0, 15.0, 20.0%). Degree substitution (DS) ranged from 0.023 to 0.365. Fourier transform infrared spectroscopy results showed a new band appearing 1730 cm−1 associated ester carbonyl groups. X-ray diffraction indicated that resulted in disappearance peaks native samples lower crystallinity indices ranging 37% (native starch) 8–11% hydrogels. Morphology analysis original granular structure lost replaced by rougher irregular structure. Water holding capacity values obtained superior those control sample (extruded without agents). Hydrogels highest or concentration (20.0%) higher DS swelling capacities, resulting 870 810% water retention, respectively. Reactive effective obtaining