Ca2+ crosslinked sodium alginate-nanocellulose as egg-box structure wraps peanut oil bodies for meat analogue

As consumers shift their preferences toward plant-based foods, low-calorie meat analogs containing solid fats remain a critical unmet need. This study constructs “egg-box” emulsion gel as a plant-based meat analog, employing sodium alginate (SA) and cellulose nanofibers (CNF) as the composite shell, peanut oil bodies (POB) as a natural lipid-filling matrix, and Ca²⁺ as a cross-linking agent. The regulatory effects of Ca²⁺ concentrations on physicochemical properties, microstructure, rheological behavior, and thermal stability of the emulsion gel were systematically investigated. The concentration of 30 mM Ca²⁺ was identified as optimal, at which the emulsion gel exhibited the most uniform microstructure, with the SA/CNF shell tightly encapsulating POB droplets. This optimal system demonstrated the highest hardness, optimal water-holding capacity, and strongest elastic network. Lissajous curve analysis successfully elucidated the interaction mechanism between the egg-box structure and the matrix, confirming the meat analog’s transition from a viscoelastic gel to a robust elastic gel. Enhanced non-covalent interactions and interconnected networks enabled superior structural integrity against mechanical disruption. However, excessive Ca²⁺ (≥40 mM) induced over-crosslinking, resulting in shell fragmentation, particle aggregation, and deteriorated functional properties. This study provides critical theoretical insights into structural design and performance optimization of plant-based meat analogs, broadening application scenarios of POB-based composites.