Recent Processing Methods for Preparing Starch‐based Bioproducts

Functional starch-based hydrogels: renewable material solutions for wastewater and agriculture industries

“…Extrusion processing is one of the most versatile and energy-efficient technologies currently used across various industries for low-cost manufacture of starch-based products such as food, paper, and textiles (Fanta et al, 2012a). Most solvent-based chemical reactions can be successfully translated and performed in an extruder via reactive extrusion (REx).…”

“…These can be improved through suitable modification methods. Starch modification techniques are broadly classified as physical, chemical, enzymatic, and genetic modification methods (Fanta et al, 2012a). Chemical reactions during starch modification alter the starch structure at both molecular and granular levels, though the relationship between the starch reactivity, and its granular and molecular structure is not completely understood (Ashogbon & Akintayo, 2014a).…”

“…Gelatinisation of starch at high temperatures and pressures using an extruder is a quick process that requires a limited amount of water. Physical destruction of granular structures during extrusion facilitates diffusion of water into the interior molecules (Fanta et al, 2012a). The intense shear force fields within the extruder tends to break down longer amylose chains, reducing the molecular order and crystallinity in starch granules, while the high processing temperature results in melting and gelatinisation but also partial depolymerisation of starch (Maningat et al, 2009).…”

“…Compared to native starches, crosslinked starches have superior mechanical, thermal and chemical resistance, which is desirable for industrial applications (Gandini et al, 2016). The crosslinking reaction is typically between two polymers or between one or more abundant monomers and small quantities of a multi-functional monomer, such as divinyl monomers, to act as a crosslinker in the presence of an initiator (Fanta et al, 2012a). Free radical polymerisation of starches with hydrophilic synthetic monomers such as acrylates, vinyls, and amides or their polymers results in the formation of starch hydrogels.…”

“…Reactive extrusion (REx) technology combines the advantage of using the extruder as a continuous flow reactor with the process of chemical reaction for synthesis and modification of starches to produce high-value starch-based products (Fanta et al, 2012a). More specifically, REx is a specific reaction carried out in a specific modular segment of a twin-screw extruder, within the residence times available during the extrusion process, using a tailored screw configuration.…”