Controlled oxidation and digestion of Pickering emulsions stabilized by quinoa protein and (-)-epigallocatechin-3-gallate (EGCG) hybrid particles

In this study, we prepared Pickering emulsions stabilized by quinoa protein isolate (QPI) and (-)-epigallocatechin-3-gallate (EGCG) non-covalent hybrid particles using ultrasonic emulsification technique and demonstrated lipid oxidation and in vitro digestion process of Pickering emulsions. The interaction forces be-tween QPI and EGCG were characterized using fluorescence spectroscopy, isothermal titration calorimetry, and Fourier transform infrared spectroscopy. Results indicated that the non-covalent QPI/EGCG hybrid particles were formed mainly via hydrophobic interactions, hydrogen bonds, and electrostatic interactions at pH 5. Then, the QPI/EGCG non-covalent hybrid particles were applied to modify the Pickering emulsion with ultrasonic homogenization. The rheological experimental results showed that the energy storage modulus (G & PRIME;) was higher than the loss modulus (G & DPRIME;), indicating that the emulsion had solid-like properties. As a physical barrier, interfacial layer fabricated by antioxidant QPI/EGCG hybrid particles limited lipid oxidation at 60 degrees C for 15 days. At 37 degrees C, the QPI/EGCG hybrid particles stabilized Pickering emulsions with robust antioxidant interfacial structure limited the lipid digestion under simulated gastrointestinal tract (gastric, small intestine phases). Thus, EGCG and quinoa proteins were more resistant to free radical oxidation and gastrointestinal digestion with the assistance of ultrasound. It provides a basis for better development of food and drug delivery systems by fully utilizing the antioxidant properties of plant polyphenols.

Automated summary

In this study, Pickering emulsions stabilized by quinoa protein isolate (QPI) and (-)-epigallocatechin-3-gallate (EGCG) hybrid particles were prepared using ultrasonic emulsification technique. The interaction forces between QPI and EGCG were characterized and the results showed that the hybrid particles were formed mainly via hydrophobic interactions, hydrogen bonds, and electrostatic interactions. The emulsion exhibited solid-like properties and the antioxidant interfacial structure provided by the QPI/EGCG hybrid particles limited lipid oxidation and digestion. This study provides a basis for the development of food and drug delivery systems utilizing the antioxidant properties of plant polyphenols.