Journal Articles
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Item Impact of thermosonication at neutral pH on the structural characteristics of faba bean protein isolate dispersions and their physicochemical and techno-functional properties(Elsevier Ltd, 2024-09) Hu Y; Cheng L; Gilbert EP; Lee SJ; Yang ZThe effect of thermosonication (TS) (90 °C, 10–30 min) on faba bean protein isolate (FPI) at pH 7 was investigated. The microstructural and techno-functional properties of TS-treated FPI were compared with native FPI or FPI treated with conventional prolonged heating (CH, up to 8 h) at 90 °C. TS treatment effectively converted FPI to amorphous aggregates containing predominant β-sheet secondary structures, as determined by Thioflavin T (ThT) fluorescence and circular dichroism (CD). According to sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), these amorphous aggregates could be formed by disulfide bonds. Additionally, TS treatment is efficient in disrupting large protein aggregates of FPI, thus improving their solubility. Both TS and CH treatments induced formation of viscoelastic FPI hydrogels, whose gel strength depends on the type and time of treatment. Hydrogels formation is likely to arise from the entanglement and interaction of protein aggregates as revealed by small angle neutron scattering (SANS) and scanning electron microscopy (SEM). TS-treated FPI was also used to prepare O/W emulsions and whose structural and physical properties were compared with those stabilised by untreated FPI. At all oil volume fractions (φ = 0.2, 0.5, and 0.7) and FPI concentrations (1, 3, and 5 wt %), emulsions stabilised by TS-treated FPI exhibited smaller oil droplet size, greater mechanical strength and superior stability compared to those stabilised by untreated FPI. The study suggests that TS treatment is promising in improving techno-functional properties of FPI; further studies are needed to exploit TS-treated plant proteins as a novel food ingredient in food product development.Item Formation and characterisation of concentrated emulsion gels stabilised by faba bean protein isolate and its applications for 3D food printing(Elsevier BV, 2023-08-20) Hu Y; Cheng L; Lee SJ; Yang ZConcentrated emulsions were prepared at a fixed oil concentration (50 wt%) using faba bean protein isolates (FPI) as an emulsifier and texturizer. Effects of FPI concentration (1, 3 and 5 wt%; at pH7), pH (pH 3, 5, 7, and 9; 3 wt%) and addition of salts (200 mM NaCl and 40 mM CaCl2; at 3 wt% FPI and pH 7) on the emulsion formation were studied. The oil droplet size and microstructural characteristics were examined by static light scattering and confocal laser scanning microscopy (CLSM), and the viscoelastic behaviours of emulsions were characterised by oscillatory rheology. At all different FPI concentrations, the emulsions formed viscoelastic gels with different gel strengths and stability due to network formation and interactions between jammed oil droplets and protein aggregates. The oil droplet size, rheological properties, and 3D printability of emulsions were not significantly changed by the presence of salts. The storage modulus G′ (1 Hz) values were higher at higher FPI concentrations, and higher pH values (i.e., pH 7 and 9) as the droplet size was smaller and the droplet packing was more compact, resulting in a better 3D printing performance. Furthermore, the heat treatment (90 °C for 30 min) remarkedly improved gel strength and the 3D printability because of protein denaturation and oil droplet aggregation. This finding demonstrated that the emulsion gel formed with FPI was tuneable for food 3D printing. Most of samples displayed high printing precision with great self-supporting capability, which may find potential applications in creating specialised diet.