High-pressure homogenised rice bran nanofibers as stabilisers in pickering emulsions: Interfacial behaviour, emulsification efficiency and oxidative stability

Rice bran nanofibers (RBNFs), derived from rice bran (RB), were investigated as sustainable, food-grade stabilizers for Pickering emulsions (PEs). RBNFs were extracted via sequential chemical treatments followed by high-pressure homogenization (HPH), designed to enhance their surface activity and interfacial performance. After 5 HPH passes at 150bars, the nanofibers exhibited an average diameter of 32 nm and significantly improved rearrangement kinetics at air-water, and oil-water interfaces (-43.67 x 10^-4s^-1 and -20.6 x 10^-4s^-1, respectively), indicating a higher affinity for interfacial rearrangement. RBNFs treated at varying HPH intensities were employed to stabilise oil-in-water emulsions. Physicochemical characterisations, including particle size distribution, zeta potential, rheological properties, confocal laser scanning microscopy (CLSM) and creaming index measurements, demonstrated that emulsions prepared at 150 bars with five HPH passes exhibited the highest colloidal stability. CLSM further revealed that RBNFs effectively adsorbed at the oil-water interface and formed a continuous network structure, inhibiting droplet coalescence. Oxidative stability was assessed at storage temperatures of 4 °C, 30 °C, and 60 °C. Emulsions stored at 4 °C displayed the greatest oxidative resistance, as determined by thio-barbituric acid reactive substances (TBARS) assays. Kinetic modelling and Q10 values provided insights into the temperature dependence of lipid oxidation, with estimated shelf-life of 110, 64 and 36 days at 4 °C, 30 °C and 60 °C respectively. These findings demonstrate the potential of RBNFs as effective Pickering stabilisers, offering a value-added approach for rice bran valorisation while supporting United Nation's SDG 7goal by sustainable energy use across food and bioproduct systems.