Rapeseed Protein Nanogels As Novel Pickering Stabilizers for Oil-in-Water Emulsions
Zhigao Wang, Nan Zhang, Chong Chen, Rong He, Xingrong Ju
Abstract
Recently plant protein Pickering particles have received tremendous interests because of their environmentally friendly, biodegradable, and safe characteristics. However, developing plant protein particles as stabilizers of Pickering emulsion still face many challenges. In current study, a novel nanogel system produced from acylated rapeseed protein isolates (ARPI) was used to stabilize Pickering emulsions. Results showed that self-assembled nanogel after native RPI modified by acylation adjusted the three-phase contact angle of ARPI nanogels system to 86.7° closing to a neutral wettability. At constant oil phase fraction (0.3, v/v), increasing the ARPI nanogels concentrations produced smaller droplet sizes of Pickering emulsions, whereas all freshly prepared Pickering emulsions were stable except 0.1% (w/v) ARPI nanogel-stabilized Pickering emulsion occurred with creaming. The rise of the oil phase fraction showed little influences on the droplets size and visual appearances of Pickering emulsions at a fixed ARPI nanogels concentration (0.75%, w/v). Moreover, the prepared ARPI nanogels stabilized Pickering emulsions were stable against aggregations of droplets at a range of pH conditions ranging from 5.5 to 8.5 and salt concentration as high as 0.2 M. Additionally, the ARPI nanogels concentration above 0.5% favored the formation of Pickering emulsion with long-term storage stability (up to 30 days) against creaming. Microscopic images evidenced that ARPI nanogels could absorb and anchor at the droplets surface forming an interfacial layer. Above findings may deliver a potential strategy for fabricating stable Pickering emulsion based on plant protein particles and are of important significance for the utilization of rapeseed protein in the food industry.