Stability of water-in-oil Pickering emulsions governed by γ-oryzanol crystallization

The development of fat-reduced food products has attracted increasing attention due to the adverse health effects associated with excessive fat consumption. Water-in-oil (w/o) emulsions, which can partially replace fat with water, represent a promising approach but require effective stabilization strategies. Conventional surfactants such as lecithin or polyglycerol polyricinoleate (PGPR) have been widely applied. However, the increasing demand for clean-label foods has stimulated interest in surfactant-free alternatives. Emulsions stabilized by food-grade particles or biopolymers have attracted increasing attention because of their long-term stability and biocompatibility. Building on this perspective, γ-oryzanol (GO), a bioactive compound from rice bran oil with antioxidant activity and cholesterol-lowering properties, was investigated as the sole stabilizer of w/o emulsions. W/O emulsions prepared by dispersing 5% (w/v) GO in the oil phase remained stable over the 30-day storage period, whereas 10% (w/v) GO could stabilize up to 50% (v/v) water and provide gel-like properties. By recrystallizing GO during homogenization, emulsions with smaller droplet sizes could be prepared. Moreover, the storage stability at 5 °C was better than at room temperature (20 °C). This work demonstrates a clean-label strategy for fabricating Pickering w/o emulsions stabilized by GO crystals for prospective food applications.