High internal phase emulsions stabilized solely by sonicated quinoa protein isolate at various pH values and concentrations

• Published in: Food chemistry Vol. 378; p. 132011
• Main Authors: Zuo, Zhongyu, Zhang, Xinxia, Li, Ting, Zhou, Jianjun, Yang, Yang, Bian, Xiaobo, Wang, Li
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.06.2022
• Subjects: Chenopodium quinoa; Emulsion stability; Emulsions; High internal phase emulsions; Hydrogen-Ion Concentration; Microstructure; Particle Size; Quinoa protein; Rheological property; Viscosity; Rheological property; Microstructure; Emulsion stability; Quinoa protein; High internal phase emulsions
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2021.132011

•HIPEs stabilized solely by sonicated QPI at various pH and c were constructed.•HIPEs at high pH presented polyhedral framework due to small spherical QPI.•HIPEs at low pH was constructed with irregular droplets due to QPI aggregates.•HIPE viscoelastic properties declined as the pH value of QPI dispersion increased.•The physical stability was enhanced with the increase of pH and concentration. In this study, stable high internal phase emulsions (HIPEs) constructed solely by sonicated quinoa protein isolate (QPI) at various pH values and protein concentrations (c) were constructed, and differences of HIPE microstructures at these conditions were discussed. HIPEs stabilized by QPI at pH 7.0, 9.0 possessed smaller droplet size (14–24 μm), smoother appearance, and higher physical stability which were caused by polyhedral framework microstructure. However, at acidic conditions, QPI aggregates filled in the gaps between droplets (30–52 μm) instead of adsorbing to oil–water interface, which decreased the stability. The solid-like viscoelasticity of HIPEs were enhanced when the c increased while the increment of pH value had the significant opposite effect (decreased from about G′ 1000 Pa, G″ 280 Pa to G′ 350 Pa, G″ 50 Pa) due to the microstructure difference. This study broadens the commercial applications of quinoa protein in novel food products like fat substitutes.