Non-thermal and porous gels: technologies for solid fat replacement in processed foods

The reduction of saturated and trans fats in formulation remains a major challenge for food engineering, as these fats provide essential structural, sensory, and processing functions. In recent years, non-thermal gels become a promising alternative to thermal gels due to their low energy requires, conveniency and high unsaturated fats preservation. This review provides a comprehensive and critical overview of non-thermal gels and porous-based gels developed for solid fat replacement under non-thermal conditions. Emphasis is placed on the underlying physicochemical mechanisms governing oil immobilisation, including pH-induced assembly, enzymatic crosslinking, ion–polymer interactions, shearing, templated gelation, and sorption-based oil confinement in porous matrices. Particular attention is given to process–structure–function relationships that link microstructure, oil distribution, texture, and stability to food performance. Recent advances in emulsion- and foam-templated systems, aerogel-based oil sorbents, natural plant-waste-derived porous materials and current applications are critically evaluated, alongside key engineering challenges, sensory quality, and formulation optimisation for future foods. By consolidating emerging knowledge across molecular, structural, and processing parameters, this review highlights the potential of non-thermal oil structuring as a viable and scalable route for the design of healthy foods with high consumer acceptance.