Transglutaminase-mediated enhancement of the stability of oil-in-water emulsions prepared using rice protein aggregates

This study aimed to improve the stability of oil-in-water emulsions using rice protein aggregates (RPAs) modified with transglutaminase (TG). RPAs were produced by heating rice protein dispersions at 90 °C for 3 h to achieve optimal aggregation. Emulsions were prepared using canola oil at 30–70% and stabilized using TG at concentrations of 1–20%. Emulsions with 30% and 50% oil exhibited uniform droplet distribution and good stability, while those with 70% oil were unstable owing to insufficient protein coverage at oil–water interfaces. Microscopy analysis confirmed that the addition of 2% TG led to consistent droplet sizes and reduced protein aggregation. Encapsulation efficiency increased with TG, particularly at 2%, but decreased at 20% TG during storage, likely because of excessive cross-linking. Lipid oxidation was suppressed in TG-treated samples after storage. Overall, moderated TG cross-linking strengthens interfacial films and enhances physicochemical stability, highlighting RPAs as potential natural, plant-based emulsifiers for food applications.