Facilitated formation of soy protein nanoemulsions by inhibiting protein aggregation: A strategy through the incorporation of polyols

Food-grade nanoemulsions fabricated using plant proteins as emulsifiers have attracted increasing interests, owing to their promising applications in food and drug sectors. However, a limitation to form nanosized droplets exists when plant proteins that usually exhibit poor emulsification performance due to their high tendency to aggregate are used as the sole emulsifier. In the current work, a facile process to form nanoemulsions using soy protein isolate (SPI) as the sole emulsifier was reported, through a strategy to inhibit protein aggregation by the addition of trehalose, as well as to improve emulsification performance of the protein. Using the microfludization as the emulsification process, the as-prepared nanoemulsions displayed extremely high stability against flocculation and coalescence during or after emulsification. Further analyses indicated that the presence of trehalose greatly inhibited protein spontaneous aggregation and prevented protein denaturation and re-aggregation of SPI during microfluidization, thus improving its emulsification performance. A kind of well-dispersed and less flocculated nanoemulsions with fine droplet sizes could be facilely fabricated using SPI as the sole emulsifier, without the occurrence of any over-processing. The findings are of value for providing a strategy to facilely prepare stable plant protein-based nanoemulsions by simply inhibiting protein aggregation with the addition of appropriate concentrations of polyols.