Comparative behaviours of homogenized amaranth, buckwheat, quinoa submicron protein particles and their effects on physicochemical properties of high internal phase emulsions

This study compared six homogenized submicron protein particles (PN) of Amaranthus hypochondriacus (AhPN), A. caudatus (AcPN), common buckwheat (CBPN), Tartary buckwheat (TBPN), white quinoa (WQPN) and red quinoa (RQPN), as stabilizers of high internal phase emulsions (HIPEs) at different oil fractions (φ = 0.75, 0.80, 0.85). The relationships of PN properties and HIPEs stability were analyzed by principal component analysis and Pearson correlations. Amaranth-PN showed higher surface hydrophobicity and contact angle (∼56°). TBPN displayed the highest phenolic content with the strongest antioxidation (DPPH, Fe²⁺) and the lowest equilibrium interfacial tension (∼9.27 mN/m). CBPN combined relatively small particles and high ζ-potential (-43.5 mV) to form dense interfacial films, yielding high moduli and viscosity, with robust gel-state HIPEs across the oil loadings. Quinoa-PN remained comparatively large particle size with high interfacial tension (∼12 mN/m) after homogenization, which produced no HIPEs at high oil fractions. This study provides direct evaluations of structure-function relationships for pseudocereal stabilizers in HIPEs, offering actionable designs for plant protein-based emulsions.