Thermosonication-induced structural remodeling of faba bean protein: Improved functionality, digestibility, and...

Faba bean protein isolate (FPI) is a promising plant-based protein ingredient; however, its compact molecular structure restricts its functional performance and bioactive potential. The effects of heat treatment (H-FPI), ultrasonication (U-FPI), and sequential thermosonication (UH-FPI) on the structural characteristics, techno-functional properties, and hypocholesterolemic activity of FPI were investigated in vitro and in vivo. Conformational changes of the protein matrix induced by ultrasound and thermosonication cause a decrease in the surface hydrophobicity, an increase in protein digestibility, and an improvement in functional properties over a wide range of pH. The in-vitro studies revealed that structural modification was also effective in improving the biological activity; in particular, the degree of hydrolysis was enhanced from 8.02 ± 2.62% (FPI) to 21.72 ± 2.25% (UH-FPI), while the micellar inhibition of cholesterol was enhanced from 23.4 ± 1.13% (FPI) to 48.5 ± 0.63% (UH-FPI) and higher HMG-CoA reductase inhibitory activity from 84.17 ± 2.65% (FPI) to 58.79 ± 3.52% (UH-FPI) indicating its potential in inhibiting intestinal cholesterol absorption and cholesterol biosynthesis. Furthermore, in vivo studies using high-fat (HF) diet-fed hamsters showed that UH-FPI improved the serum lipid profile and cholesterol metabolism-related proteins. The expression analyses further confirmed that UH-FPI upregulated the expression of cholesterol efflux-related proteins (ABCG5 and ABCG8), hepatic cholesterol metabolism regulators (LXR-α, CYP7A1, and LDL-R), and downregulated the expression of the intestinal cholesterol uptake-related protein NPC1L1 upon normalization with the HF group. The results indicate that thermosonication could be used to alter faba bean protein's structure and modulate cholesterol metabolism, leading to improved functional and hypocholesterolemic properties, making it a suitable functional food ingredient for the promotion of cardiovascular health.