Aerogel-based oil sorbents derived from pomelo (Citrus grandis L.) peels as potential gel matrices for food applications: Formation, properties and in-vitro oral processing

This study demonstrates the transformation of pomelo peel (PP) into aerogel templates for efficient rice bran oil absorption, producing effective oil sorbents. PP powder (5–10% w/w) of 125 and 250 μm particle sizes was emulsified with water, treated hydrothermally at 95 °C for 2 h, and freeze-dried to form aerogels. Upon immersion in oil, these templates formed gel-like sorbents. Aerogels with higher PP content exhibited an increase in density (from 26.65 to 77.75 mg/cm³), porosity (from 90.54% to 96.51%), and hardness (from 14.27 to 169.76 N), while cohesiveness decreased (from 40.00% to 21.59%) due to particle-to-particle interactions. The 250 μm PP-based aerogels with 5%–7% PP content demonstrated superior oil-holding capacity compared to the 125 μm ones; however, this capacity decreased as PP content increased from 8% to 10%. Microstructural analysis revealed a mix of mesopores and micropores, with mesopores dominating at lower PP concentrations. Fourier transform infrared spectroscopy (FTIR) analysis confirmed chemical changes post-treatment, yet no new peaks emerged after oil sorption, indicating a mainly physical process. Sorbents with lower PP content (5–6%) exhibited greater cohesiveness, increasing from 27.01% to 40.00%, due to particle-to-oil interaction, making them more suitable for food applications, as they broke down fully during in-vitro oral processing. Higher PP content (8%–10%) resulted in a high friction coefficient, rendering it unsuitable as a fat replacer. In contrast, sorbents with lower PP content sorbents (5%–7%) exhibited a decrease in lubrication as PP content increased, as indicated by measurements of oil release, droplet size, tribology, bolus fragmentation, and viscosity. This method offers potential for fat replacers and functional food ingredients.