Physico-chemical, functional, and structural properties of un-defatted, cold and hot defatted yellow lupin protein isolates

This study investigates the structure, physico-chemical and functional properties of yellow lupin isolate protein (YLPI) obtained by different processes (conventional wet and purely aqueous fractionation) from un-defatted (YLPIU), and hot (YLPIHD) and cold (YLPICD) defatted flour. The defatting process modified the physical, structural and functional characteristics of lupin protein isolates. Indeed, a decrease of alpha-helix, free sulfhydryl groups amount and an increase of disulfide bond levels were observed for defatted samples, improving their emulsifying stability. The defatting process exposes the hydrophobic groups present within the YLPI, which increases total sulfhydryl content and protein surface hydrophobicity. Hot and cold defatting induced a decrease in turbidity, water-holding capacity, oil adsorption capacity, tapped and poured bulk densities. In addition, the defatting process changed the particle size of protein isolates that induced changes in their viscosity. Tryptophan spectra and protein surface hydrophobicity indicated that YLPICD and YLPIHD underwent structural conformational change during the defatting process.

Automated summary

This study investigates the structure, physico-chemical and functional properties of yellow lupin isolate protein obtained by different processes. The defatting process modifies the physical, structural and functional characteristics of lupin protein isolates. The defatting process improves the emulsifying stability and changes the particle size and viscosity of the protein isolates.