The influence of pea protein and sugar particles and their blends on the rheology and crystallisation behaviour of oils

This is the authors' abstract. We don't add key points for this paper.

Chocolate is a complex colloidal system of multiple dispersed particle types, including sugar, cocoa solids and often dairy proteins. However, the use of plant proteins in such systems remains unexplored. This study investigates the behaviour of pea protein isolate (PPI), sugar particles and their blends in oil, focussing on their effects on the rheological and crystallisation properties of cocoa butter (CB). Both PPI and sugar particles aggregate in CB, increasing viscosity and forming elastic oleogel-like systems. In blended systems, PPI disrupted sugar particle-particle interactions. Greater sugar particle aggregation was observed in sunflower oil, attributed to surface-active impurities in CB acting as dispersants for hydrophilic particles. Oil type had little influence on PPI aggregation and the modified MPQ-rcp model indicated that PPI and sugar particles exhibit similar interactions in CB. PPI accelerated CB crystallisation, whereas the presence of sugar delayed crystallisation, so that mixed particle systems had similar kinetics to pure CB. Over extended storage, concentrated particle suspensions curb the solid fat content (SFC), attributed to the restricted mobility of oil due to the high dispersed volume fractions - as visualised by Raman microscopy. At low SFC, particles are active in the fat crystal network, increasing elasticity. However, at high SFC, the elasticities were comparable to that of pure CB. This demonstrates the potential of plant protein particles to provide rheology modification benefits to sugar-oil mixtures, and to reduce solid fat content, providing a foundation for the development of more sustainable and nutritious confectionery systems.