Edible oil powders based on spray-dried Pickering emulsion stabilized by soy protein/cellulose nanofibrils

Abstract

Stable O/W Pickering emulsions synergistically stabilized by heat-induced soy protein isolate (HSPI) and bacterial cellulose nanofibrils (BCNFs) were fabricated, and spray-dried to obtain edible oil powders. The emulsions with 0.2 wt% BCNFs and 2 wt% HSPI displayed homogeneous droplets size (<1 μm) and narrow size distributions, and had no obvious droplet aggregates at different oil phase ratios (10–20%) with 2 wt% beeswax. After spray drying, the obtained stable oil powders (35.9–56.8%) presented hollow smooth spherical structure with small and uniform size. The moisture content, flowability, bulk density and encapsulation efficiency of oil powders were improved by tuning the BCNFs contents and oil-to-water ratios of emulsions. Furthermore, the presence of BCNFs partially inhibited lipid hydrolysis, and oil powders with 0.1 wt% BCNFs performed optimum anti-digestibility with the minimum released FFA values of 72.5%. This work combined spray drying technique with Pickering emulsions for oil encapsulation, and optimized the emulsions properties to address the limitations of spray drying for liquid oil microencapsulation, which would provide some guidance for oil powders development.