Regulation\nof Adsorption Properties of Whey Protein\nIsolate Fibril–Calcium Alginate Aerogels by Controlling Protein\nFibrillation Time

Amyloid-like fibrils have a relatively high specific\nsurface area,\nwhich makes them suitable as absorbents. In this study, we prepared\nabsorbent composite aerogels from whey protein isolate fibril (WPIF)\nand calcium alginate (CA). The impact of protein fibrillation time\n(4–24 h) on the adsorption properties of these aerogels was\nassessed, as this influences the nature of the WPIFs formed. Fourier\ntransform infrared spectroscopy analysis indicated that hydrogen bonding,\nhydrophobic interactions, and electrostatic interactions were the\nmain molecular interactions in the composite aerogels. Then, the adsorption\nproperties of the aerogels were investigated using crystal violet\nas a model compound. The adsorption properties of all composite aerogels\nwere significantly improved compared to CA aerogels, which was mainly\nattributed to the numerous functional groups of the surfaces of the\nWPIFs, as well as the rougher surface topology of the composite aerogels.\nThe adsorption capacity of the composite aerogels first increased\nand then decreased with increasing fibrillation time, with 8 h fibrillation\nleading to the largest adsorption capacity (1886.11 mg/g). Thioflavin\nT fluorescence, atomic force microscopy, light extinction, average\nparticle size, and zeta potential analysis indicated that the high\nfibril content, mature fibril morphology, large number of available\nfunctional groups on the surface, and relatively low zeta potential\nof WPIF8 might be the main reasons. Adsorption kinetics and isothermal\nadsorption profile analysis suggested that monolayer adsorption occurred\nthrough chemical adsorption processes. The edible aerogel with high\nadsorption properties developed in this work has potential application\nin food and biomedical fields.