Browsing by Author "Cheng L"
Now showing 1 - 2 of 2
Results Per Page
Sort Options
- ItemFibrillisation of faba bean protein isolate by thermosonication for process efficacy: Microstructural characteristics, assembly behaviour, and physicochemical properties(Elsevier Ltd, 2024-09) Hu Y; Cheng L; Gilbert EP; Loo TS; Lee SJ; Harrison J; Yang ZThe effect of thermosonication (TS) (90 °C, 10–30 min) on the fibrillisation of faba bean protein isolate (FPI) was studied. The self-assembly behaviour, microstructural characteristics and techno-functional (gelation and emulsification) properties of FPI fibrils obtained from TS treatment were compared with those obtained from conventional prolonged heating (CH) at 90 °C up to 8 h. Compared to CH treatment, TS treatment was shown to significantly accelerate the formation of FPI fibrils with prominent β-sheet structures as revealed by Thioflavin T (ThT) fluorescence, Fourier-transform infrared spectroscopy (FTIR) and circular dichroism (CD). The characteristics of fibril building blocks were analysed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and liquid chromatography linked to tandem mass spectrometry (LC-MS/MS) to obtain the differences between TS and CH induced fibrillisation of FPI. Transmission electron microscopy (TEM) and small-angle neutron scattering (SANS) showed that 4 h CH and 10 min TS treatments resulted in the fibrils with similar radius (from 5 to 10 nm). Furthermore, SANS indicated that TS treatment induced the formation of an entangled FPI fibrillar network, which could lead to the observed viscoelastic properties of FPI at a high concentration (10 wt%). Finally, high internal phase O/W emulsions (HIPE, φ = 0.75) stabilised by 30 min TS induced FPI fibrils (3 wt%) demonstrated a stronger gel strength and smaller oil droplet size compared to those prepared with untreated FPI, suggesting a superior emulsification capability of FPI fibrils. This finding demonstrates that TS treatment is a promising and efficient method for fibrillisation of plant proteins with the resultant fibrils generating excellent gelation and emulsification properties.
- ItemLimited Alcalase hydrolysis improves the thermally-induced gelation of quinoa protein isolate (QPI) dispersions(Elsevier BV, 2022-11-01) Wang X; Cheng L; Wang H; Yang ZGelation is critical in many food applications of plant proteins. Herein, limited hydrolysis by Alcalase was used to promote thermally induced gelation of quinoa protein isolates (QPI). Mechanical properties of various QPI gels were characterised by small and large oscillatory shear deformation rheology while the microstructural features were observed by confocal laser scanning microscopy (CLSM). Both the gel strength and microstructure are strongly related to the hydrolysis time. The maximum gel strength (∼100 Pa) was achieved after Alcalase hydrolysis for 1 min, which was ∼20 folds higher than that of untreated QPI. Extended hydrolysis up to 5 min progressively decreased the gel strength. A string-like interconnected protein network was formed after proteolysis. The change of gel strength with hydrolysis time correlated well to the Gʹ 20°C/Gʹ 90°C value and results of intrinsic fluorescence and surface hydrophobicity. The Gʹ 20°C/Gʹ 90°C value is sensitive to hydrogen bonds formation while the intrinsic fluorescence and surface hydrophobicity are associated with protein unfolding and exposure of hydrophobic groups. Therefore, both hydrogen bonding and hydrophobic interactions are critical in improving the gel strength of QPI hydrolysates. Finally, FTIR analysis revealed that protein secondary structures are affected by the proteolysis and formation of inter-molecular hydrogen bonds between polypeptides. This study provides an efficient strategy for improving thermally induced gelation of QPI and enables a deep understanding of QPI gelation mechanism induced by Alcalase hydrolysis.