Pickering emulsions from rice protein-xanthan gum nanoparticles at different oil content: emulsion properties and using producing cake as a fat replacer

In the present study, Pickering emulsions with different oil content (15%(PE15),30 (PE30), 45(PE45), and 60 (PE60)) were created with nanoparticles produced from rice protein isolate (RPI) and xanthan gum (XG). The aim was to produce cakes with reduced oil content with these emulsions. For this purpose, firstly the emulsion properties were evaluated. Emulsion activity (EAI)-stability indexes (ESI), ζ-potentials, and nanoparticle structures of the emulsions were investigated. The EAI value was determined as 54.14±3.19 m2/g and 54.15±0.95 m2/g for the emulsions containing 15% and 30 (w/w) oil, respectively, while the lowest EAI value was determined as 30.12±0.89 m2/g for the emulsion containing 60% oil. While the ζ-potential value decreased with increasing oil concentration, oil globule diameters increased. Pickering emulsions with 15%, 30, 45, and 60 oil (C-PE15, C-PE30, C-PE45, and C-PE60) and a control sample were produced with oil. The features of cakes made using emulsions with different oil contents were examined, including measuring the viscosity of batter, baking loss, symmetry index, moisture content, ash content, and sensory analysis. When viscosity values are examined, it can be said that the lowest value was generally recorded in the cake batter prepared with PE15. The pH values decreased as the oil content in the cake batter increased. Baking loss and symmetry index did not significantly differ (p>0.05) between cakes made with emulsion and control. The decrease in the oil ratio in the emulsion and the increase in the RPI-XG nanoparticle solution ratio increased moisture. As a result, RPI-XG nanoparticles are a suitable material for producing Pickering emulsion. Additionally, cakes can be made with the emulsions that are formed. For product compositions with minimal oil content, the usage of PE15 emulsion can be suggested.