**Background:** Pickering emulsions (PEs) are stabilized by solid particles rather than conventional surfactants or emulsifiers. Interest in PEs has grown over the past two decades due to concerns about petroleum-based stabilizers and consumer demand for clean-label, vegan, and cruelty-free products. This review provides an updated overview of PEs stabilized with inorganic solid particles, covering stabilization mechanisms, particle types, production processes, and food applications, with a special focus on hydroxyapatite (HAp).
**Methods:** The authors conducted a narrative review of the literature on PEs stabilized by inorganic solid particles, including silica, calcium carbonate, and hydroxyapatite. They examined particle characteristics (wettability, size, shape, surface charge), aqueous and oil phase properties, production techniques (high-shear mixers, ultrasonic homogenizers, high-pressure homogenizers, microfluidizers, membrane homogenizers, and static mixers), and food applications. Data were collected from the ISI Web of Science up to February 2023.
**Key Results:** The stabilization of PEs relies on three main mechanisms: capillary forces, particle–particle networks, and desorption energy. Particle wettability, characterized by the three-phase contact angle (θ), determines emulsion type: for 15° < θ < 90°, particles are hydrophilic and form O/W emulsions; for 90° < θ < 165°, particles are hydrophobic and form W/O emulsions. Particle size is typically in the nanometric range (5–10 nm to ~800 nm). Non-spherical particles (rods, ellipsoids, cubes, peanuts, discs) can improve stability compared to spherical particles; for example, silica rods stabilize emulsions for months versus hours for spherical silica. Increasing particle concentration improves stability—silica at 9 wt% yielded emulsions stable over 2 years, while HAp above 5 wt% gave stable emulsions for 2 months. Silica particles reduced lipid oxidation by approximately 50% compared to conventional emulsifiers. Silica-stabilized PEs achieved ~80% curcumin retention after simulated gastric digestion and ~60% release after 2 hours of simulated intestinal digestion. HAp-stabilized PEs loaded with vitamin E showed 3.3-fold (gelatin) and 6-fold (milk) increases in bioaccessibility when incorporated into food matrices. HAp particles dissolve rapidly at pH ~1–2 (gastric conditions) into Ca²⁺ and PO₄²⁻ ions, with no cytotoxicity reported. Production methods vary: high-shear mixers (2,500–30,000 rpm, 30 s–6 min) are most common but yield broad droplet size distributions; membrane emulsification produces droplets 3–9 times larger than membrane pore size; static mixers like NETmix achieved minimum droplet sizes around 7 µm at Re=400 and 17 cycles.
**Clinical Implications:** PEs offer a platform for developing functional foods with reduced saturated fat content and enhanced delivery of bioactive compounds. They can serve as carriers for lipophilic vitamins (A, D, E, K), curcumin, and omega-3 fatty acids, improving their stability and bioaccessibility. The use of food-grade inorganic particles (silica, calcium carbonate, HAp) with GRAS status supports regulatory acceptance. HAp's rapid dissolution in gastric acid and lack of cytotoxicity make it a safe candidate for oral delivery systems. PEs can also enable fat reduction in processed foods (e.g., replacing ~50 wt% of chocolate fat with fruit juice via W/O PEs) and the development of vegan mayonnaise alternatives. However, challenges remain in scaling production, ensuring compatibility with food matrices, and establishing comprehensive safety data for novel particles.