Rheological and Textural Insights Into Crosslinked Buckwheat and Rice Starch Gels and Their Aerogel Applications
摘要
In the present study, buckwheat (BS) and rice starches (RS) were crosslinked with 6% and 12% sodium trimetaphosphate (STMP), and their gels (at 5, 10, and 15% concentration) were analyzed for steady and dynamic rheology, creep recovery, and textural behavior. Rheological analysis revealed that crosslinked starches exhibited lower shear stress and viscosity than native starches due to reduced retrogradation, with BS showing higher viscosity than RS due to its higher amylose content. However, dynamic rheology demonstrated that crosslinking improved the viscoelastic properties, increasing elasticity and structural integrity. In addition, textural properties of starch gels generally improved after prolonging the retrogradation time (48 h). Based on the rheological and textural properties, starch aerogels were prepared using native and crosslinked RS and BS at 10 and 15% concentrations. Bulk density ranged from 0.121 g/cm3 (12% STMP BS at 10% concentration) to 0.332 g/cm3 (native BS at 15% concentration), while porosity varied between 76.84% and 88.62%. Native RS aerogels exhibited higher porosity and water absorption (upto 790%) due to lower retrogradation, whereas BS aerogels showed greater thermal stability and compressive strength (upto 17.46 N). BET surface area ranged from 5.17 to 11.46 m2/g and thermal conductivity was observed as low as 0.0615 W/m·K.