Designing hybrid food structures: network emulsions and porous solids via citrus fiber integration

Citrus fruits are the most cultivated fruit category worldwide, and juice extraction generates substantial by-products, accounting for 50–60% of the processed material. These residues contain essential oils, pectins, and insoluble dietary fiber. While essential oils and pectin have been widely studied, the insoluble fiber fraction remains underexploited in food applications. Understanding its functional and physicochemical properties could enhance citrus by product valorization and support the development of innovative, naturally derived food systems (Tan et al., 2024).Citrus fiber is able to stabilize an oil-in-water emulsions, creating a network microstructure (Panzanini et al., 2025). This study introduces a new interpretation of these emulsions as porous solids that self‑assemble around the dispersed phase. Rheology and microscopy are used to visualize and investigate this hypothesis. Emulsions containing different fiber (3–5% w/w) and oil (20–30% w/w) concentrations are dispersed in water or apricot purée and subjected to centrifugation and freeze-thaw cycles. Stabilization is strongly influenced by the dispersing medium: aqueous systems exhibit an improved resistance to applied stress, whereas apricot-based matrices show a greater structural mobility and reduced mechanical stability. Higher fiber levels produce denser networks behaving similarly to porous structures, enabling controlled release of the dispersing phase. Viewing network-based emulsions as porous solids provides a useful framework for interpreting their functionality and highlights citrus fiber as a promising structuring agent for next-generation food formulations with tunable stability and release properties.