Structure and stability characterization of pea protein isolate-xylan conjugate-stabilized nanoemulsions prepared using ultrasound homogenization

Preparation of pea protein isolate-xylan (PPI-X) conjugate-stabilized nanoemulsions using ultrasonic homoge-nization and the corresponding structure and environmental stability were investigated in this study. Conditions used to prepare nanoemulsions were optimized using a response surface methodology as follows: protein con-centration 8.86 mg/mL, ultrasound amplitudes 57 % (370.5 W), and ultrasound time 16 min. PPI-X conjugate -stabilized nanoemulsions formed under these conditions exhibited less mean droplet size (189.4 +/- 0.45 nm), more uniform droplet distribution, greater absolute value of zeta-potential (44.8 +/- 0.22 mV), and higher protein adsorption content compared with PPI-stabilized nanoemulsions. PPI-X conjugate-stabilized nanoemulsions also exhibited even particle distribution and dense network structure, which might be reasons for the observed high interfacial protein adsorption content of conjugate-stabilized nanoemulsions. Moreover, better stability against environmental stresses, such as thermal treatment, freeze-thaw treatment, ionic strength and type, and storage time was also observed for the conjugate-stabilized nanoemulsions, indicating that this type of nanoemulsions possess a potential to endure harsh food processing conditions. Therefore, results provide a novel approach for the preparation of protein-polysaccharide conjugate-stabilized nanoemulsions to be applied as novel ingredients to meet special requirements of processed foods.

Automated summary

This study investigated the preparation, structure, and environmental stability of PPI-X conjugate-stabilized nanoemulsions. The optimized conditions for preparing the nanoemulsions resulted in smaller droplet size, more uniform distribution, higher zeta-potential, and higher protein adsorption content compared to PPI-stabilized nanoemulsions. The conjugate-stabilized nanoemulsions also exhibited even particle distribution, dense network structure, and better stability against environmental stresses. These findings suggest that this type of nanoemulsions could be used as novel ingredients that can withstand harsh food processing conditions.