Protein-dense droplets to powders: creating low-viscosity colloidal plant protein ingredients

Abstract

Plant proteins offer a sustainable alternative to animal-based ingredients; however, they often suffer from uncontrolled aggregation, reduced dispersibility, increased viscosity, and more complicated processing. In this study, we developed a method to produce a powder of colloidal plant protein particles from a commercially sourced, air-classified yellow pea protein concentrate.

The method involves gradual acidification near the isoelectric point, resulting in heat-set protein-dense droplets that are spray-dried into a colloidal protein powder with a 61 % w/w protein content. This process was compatible with conventional wet extraction protocols and required no specialised equipment or additional processing steps. We confirmed that hydrogen bonding and hydrophobic interactions stabilise the protein-rich particles, which contain approximately 35 % (w/w) protein and exhibit nearly 2-fold higher water-holding capacity. We investigated the powder's wettability and dispersibility, observing that the colloidal protein powder demonstrates markedly improved wettability compared to a conventional protein concentrate. At dry matter concentrations exceeding 15 % (w/w), the colloidal pea protein dispersions showed up to 10-fold (at 20 % w/w) lower shear viscosity than their conventional counterparts, particularly after heat treatment. Additional shear processing and homogenisation further reduced viscosity, with the most significant effects observed in heat-treated dispersions.

In conclusion, this study presents a versatile process for producing plant protein concentrate from colloidal protein particles formed via gradual acidification. The resulting particles exhibit high internal protein content, while the spray-dried powder demonstrates improved wettability and low viscosity at 15 %w/w and higher solids content.