Cellulose nanofiber and soy protein isolate synergistically enhance freeze–thaw, storage, and photostability of Pickering emulsions

Pickering emulsions offer high stability and biocompatibility, making them promising for food applications. The preparation of stabilizers using deep eutectic solvents (DES) supports green chemistry principles. This study compared cellulose nanofiber (CNF) prepared using two DES-based methods: L-CNF, obtained chemically with malic acid/choline chloride, and G-CNF, produced physically by glycerol/choline chloride ball milling, with microcrystalline cellulose (MCC) as the control. L-CNF exhibited the smallest size (82.8 ± 2.0 nm), highest surface charge (−24.5 ± 0.4 mV), and lowest interfacial tension (16.57 ± 0.45 mN·m⁻¹). When combined with 1.0 wt% soy protein isolate (SPI) at 0.4 wt% L-CNF, fine droplets and a strong viscoelastic network formed, resulting in excellent freeze–thaw and storage stability. At a 3:7 oil-to-water ratio, creaming was minimized, antioxidant performance improved, and creaming index remained 19.5% after 6 months of simulated light exposure. MCC and G-CNF showed weaker stabilization, highlighting the importance of DES preparation in emulsion design.