The Reactive Extrusion Cationization of Starches as a Novel Physicochemical Surface Modification Method

The modification of starches by cationization is a fundamental physicochemical process aimed at improving their physicochemical properties and expanding their industrial applications. Traditionally, this modification is associated with long duration, high energy consumption, and waste generation. This article proposes a method based on reactive extrusion (REX) as a sustainable alternative for modifying corn (Zea mays everta) and chayote roots (Sechium edule) or chinchayote starches. A single-screw extruder was utilized to assess the effects of temperature on the degree of substitution (DS) and the functional and structural properties of the modified starches. Glycyltrimethylammonium chloride (GTAC) was used as a cationizing agent in both methods, REX and conventional cationization (CT), at a concentration of 3%. The results indicate that extrusion can produce starches with a DS equivalent to that obtained by CT in the case of corn starch (0.21-0.23). Rheometry shows a decrease in the viscosity peaks due to the pre-gelatinization process. Calorimetry showed a decrease in enthalpy and an increase in tractability temperature for the REX-modified starches due to the temperature and shear to which they were subjected. The spectroscopic technique showed the incorporation of GTAC into the starch structure. The results of physicochemical characterization show that the REX is identified as a viable alternative to CT, offering a faster, more energy-efficient, and environmentally friendly process. The effectiveness of REX in altering the physicochemical properties of starch suggests its potential for innovative industrial applications, such as water treatment or the production of biodegradable materials.