Supercritical fluid extrusion: Die design and physicochemical properties of milk protein extrudates. (March 2021)

• Record Type: Journal Article
• Authors: Arora, Bindvi; Singha, Poonam; Rizvi, Syed S.H.
• Is Part Of: Innovative food science & emerging technologies. Volume 68(2021)
• Publication Date: 2021-03
• Subjects: Die design -- Milk protein concentrate -- Protein-protein interactions -- Surface hydrophobicity -- Rheological properties; Food -- Biotechnology -- Periodicals; Food industry and trade -- Technological innovations -- Periodicals; Aliments -- Biotechnologie -- Périodiques; Food -- Biotechnology; Periodicals; Electronic journals; 664.005
• DOI: 10.1016/j.ifset.2021.102637
• Languages: English
• ISSNs: 1466-8564

Abstract

Abstract: Extrusion processing has been used to modify the functional properties of proteins. The protein-protein interactions, surface hydrophobicity, and rheological properties of milk protein concentrate extruded using dies of different geometries (circular, annular and slit) were quantified. With the same extrusion treatment history prior to the die, extrudates generated using dies with higher wall shear (slit 1.4 × 10 4 s −1 > annular 1.1 × 10 4 s −1 > circular 2.9 × 10 3 s −1 ) showed greater protein extractability, higher index of surface hydrophobicity, and enhanced water solubility index indicating significant breakdown of protein aggregates. Higher viscoelastic moduli (G' and G") and apparent viscosity were observed for slit die extrudate dispersions. However, low flow behavior indices (0.04–0.23(−)) and a high viscous activation energy (43 kJ/mol) of slit die extrudate dispersions implied their shear and temperature sensitivity, respectively. Thus, extrudate functionality can be optimized by selection of the appropriate die design. Highlights: Electrostatic and non-covalent bonding were major interactions in extruded MPC. High shear dies resulted in greater breakdown of protein aggregates. High shear dies resulted in higher surface hydrophobicity of extruded proteins. Viscosity of slit die extrudate dispersion was most shear and temperature dependent.