Process optimisation and product characterisation of milk protein concentrate extrudates expanded by supercritical carbon dioxide

Abstract

The effects of water and supercritical CO2 (SC–CO2) addition rate, and pressure at SC–CO2 injection (PCO2) on physical and rheological properties of milk protein concentrate (MPC81) and MPC81‐sucrose (MPC81‐S) extrudates were investigated. As PCO2 increased, extrudate expansion decreased and storage modulus and hardness increased. PCO2 for MPC81 and MPC81‐S was optimised as 13.78 MPa and 11.03 MPa, respectively, whereas water rate of 40 (wt. % dry feed) and SC–CO2 rate of 2.25 (wt. % dry feed) were optimised for both formulations. Elucidating the association of extrusion parameters and extrudate properties will facilitate the development of MPC extrudates of commercial utility.