Impact of High-Pressure Homogenization on Physicochemical, Structural, and Rheological Properties of Quinoa Protein Isolates

Abstract

The impact of high pressure homogenisation (HPH) on physicochemical, microstructural, and rheological properties of quinoa protein isolate (QPI) suspensions were studied. Individual protein patterns kept unchanged with HPH treatment up to 500 bar, as revealed by SDS-PAGE. After HPH treatment at 500 bar, large protein aggregates were disrupted, and particle size was substantially reduced from ~8.2 to 0.5 µm. Concurrently, water solubility, emulsifying, and foaming capability were significantly enhanced. QPI molecules after HPH treatment became more flexible and absorbed at the air-water and oil-water interfaces faster, resulting in a more rapid decrease of surface tension and interfacial tension. The secondary structure of QPI proteins was not significantly altered after HPH treatment as probed by FTIR. All QPI suspensions formed weak gels after thermal treatment (85 °C, 30 min), and HPH treated QPI suspensions resulted in a stronger gel strength with a more compact and homogeneous protein network microstructure. These results show that HPH treatment could be an excellent processing technique to modify the physicochemical, functional, microstructural, and gelation properties of QPI suspensions.