Hydrogels based on mucilage of underutilized cereals: Synthesis and characterization

Abstract

Mucilage is a natural polysaccharide with a variety of physicochemical and structural properties. Plant-derived mucilage has a wide range of applications, such as binding agent, stabilizer, emulsifying agent, thickening agent, and gelling agent. This study investigated the potential of underutilized cereals’ mucilage and further explored their application by synthesizing mucilage-based hydrogels. For this purpose, we have explored four new sources of mucilage, namely adzuki beans (A_b), amaranth (A_m), proso millet (P_r), and little millet (L_m). The underutilized cereals’ mucilage application has been examined by developing hydrogels through the free radical co-polymerization technique. Mucilages are confirmed to be a natural thickening and a substitute for synthetic polymers after being evaluated physically and phytochemically. Structural analysis of mucilages and their hydrogels (A_bH, A_mH, P_rH & L_mH) were characterized by using FTIR-ATR, XRD, ¹H & ¹³C NMR techniques. It confirms that all four mucilages are rich in polysaccharide residues and grafting of sodium acrylate has been successfully done on mucilages. Thermal gravimetric analyses represent the better thermal stability of the synthesized hydrogels than their respective mucilages. SEM confirms the porous structure of the mucilages and their hydrogels. All of these studies demonstrated that the underutilized mucilage from cereals might be a good feedstock for a hydrogel-forming agent, which can be explored in the food, cosmetics, and pharmaceutical industries.