Changes in Emulsifying Properties, Droplet Size, Turbidity and Lipid Oxidation of Pea Protein Nanoemulsions Exposed to High-Intensity Ultrasound and High-Pressure Homogenization during Storage

Abstract

The current work was conducted to explore the influence of two non-thermal technologies (high pressure homogenization (HPH) and high-intensity ultrasound (HIU)) on emulsifying properties, droplet size, turbidity and lipid oxidation of pea protein-stabilized nanoemulsions (PPNs) during seven days of storage. The smallest droplet size (198.3 nm) was obtained for the samples exposed to 10 min HIU at 100% amplitude among all treatments. The same sample also showed the least lipid oxidation (98 mmol/kg) during storage. There was a positive relationship between droplet size and turbidity values. All HIU-treated PPNs exhibited less turbidity and smaller droplet size where the control PPN samples demonstrated the most turbid structure (4.05) with the biggest droplet size (413.9 nm). Similar positive relationship was also found between the variables of droplet size and lipid oxidation. All HIU-treated PPNs exhibited less lipid oxidation and smaller droplet size where the control PPNs demonstrated the most lipid oxidation with the biggest droplet size. Last but not least, among the treatments, the PPNs exposed to 10 min HIU at 100% amplitude showed the highest emulsifying activity index (EAI, 212 m2g-1) and emulsifying stability index (ESI, 59 min), whereas the PPNs with no treatment showed the lowest EAI (69 m2g-1) and ESI (21 min).