Formation of gel-like sorbents by pomelo (Citrus grandis L.) peel powder via a rapid nonthermal approach: Role of particle size, water addition, powder concentration and drying method

• Freeze- (FDPP) and oven-dried pomelo peel (ODPP) were milled to 125 and 250 μm • FDPP and ODPP were used as absorbents to form gel-like sorbents at room temperature • FDPP showed a higher antioxidant capacity and porosity than ODPP • Sorbents formed by FDPP showed a higher strength and stability than ODPP • Adding a water phase disrupted the structure and decreased the strength of sorbents • Increasing particle size and concentration led to hard but brittle sorbents Pomelo peel (PP) is a plant waste which is rich in antioxidants and can absorb oil to form semi-solid sorbents. This study developed a robust non-thermal approach to produce gel-like sorbents by directly mixing pomelo peel powder with oil, or water-in- oil emulsion. The effects of drying method, particle size, PP content, and water addition were systematically investigated. Freeze-dried (FD) PP exhibited higher antioxidant capacity and porosity than oven-dried (OD) PP, thereby reducing the amount of PP required for sorbent formation and enhancing gelling strength and oil-holding capacity. Particle size governed the gelling mechanism: 500 μm PP could not form self-sustained sorbents, 250 μm PP formed particle-to-particle interactions, whereas 125 μm PP formed particle-to-droplet interactions, resulting in larger aggregates and uniform microstructures, respectively. Consequently, 125 μm sorbents were more elastic than 250 μm sorbents. The introduction of a sorbent with reduced oil phase decreased the uniformity and mechanical strength of the matrix by disrupting its structure. Water reacts with soluble fibres in FD samples providing them with a higher strength than OD samples, but still being weaker than those without water. Oil loss decreased with increasing PP content, particle size, and was consistently lower in FD than in OD sorbents due to the high porosity of the former. Moreover, FD sorbents exhibited superior lipid stability compared with the OD counterparts, attributed to their higher antioxidant capacity. Overall, the physicochemical properties of PP-based sorbents were comparable to those of conventional oleogels, highlighting their potential as sustainable fat replacers in food applications.