Abstract
Abstract
Ultrasonication (20 kHz, 19.9 W/10 mL sample) was used to form O/W emulsions stabilised by quinoa protein isolate (QPI) particles at 3 wt%. Effects of pH (3, 5, 7, 9) and oil contents (20%, 40%, and 60%) on rheological properties and microstructural characteristics of emulsions were investigated. All emulsions show viscoelastic behaviours and form a network structure comprising aggregated oil droplets and QPI particles. Emulsions stabilised by QPI at pH 5 showed largest droplet sizes and lowest gel strength due to extensive aggregation of proteins around the isoelectric point (pI ~ 4.5). The gel strength (G´(1 Hz)) were enhanced when the oil content increased and reached ~ 1100–1350 Pa at 60% oil content at different pH. This could be attributed to a tighter packing of oil droplets at 60% oil. Confocal laser scanning microscopy (CLSM) and transmission electron microscopy (TEM) revealed that interdroplets bridging and voids filling of QPI particles between oil droplets are critical in formation of aggregated emulsions network. Emulsions stabilised by QPI at pH 7 and 9 possessed thinner interfacial layers compared to those at pH 3 and 5. Finally, this study shows a potential of using ultrasonication to prepare gel-like emulsions stabilised by QPI, broadening applications of quinoa proteins in making dairy substitutes with semi-solid textural characteristics.
Publisher
Research Square Platform LLC
Reference45 articles.
1. A. Taha et al., Ultrasonic emulsification: An overview on the preparation of different emulsifiers-stabilized emulsions (Trends in Food Science & Technology, 2020)
2. W. Li, G.J.O. Martin, M. Ashokkumar, Turbulence-Induced Formation of Emulsion Gels. Ultrasonics Sonochemistry, 2021: p. 105847
3. A study of the effectiveness and energy efficiency of ultrasonic emulsification;Li W;Phys. Chem. Chem. Phys.,2018
4. Comparison of oil-in-water emulsions prepared by ultrasound, high-pressure homogenization and high-speed homogenization;Zhou L;Ultrason. Sonochem.,2022
5. Effect of different oils and ultrasound emulsification conditions on the physicochemical properties of emulsions stabilized by soy protein isolate;Taha A;Ultrason. Sonochem.,2018