Mechanical and microstructural properties of milk whey protein/espina corona gum mixed gels

Abstract

Mechanical and microstructural properties of gels composed of whey protein isolate (WPI) and Espina Corona Gum (ECG) were studied. WPI gels were made varying the protein concentration from 12 to 16g/100g while mixed gels were obtained at 12g/100g protein and varying ECG concentration from 0.12 to 0.60g/100g. All gels were obtained by heat treatment (30min, at 80°C). Mechanical properties were studied by uniaxial compression and stress relaxation test and gelling properties were discussed in terms of pore size, opacity index, colour parameters and microstructure. Stress (maximum stress) and deformability (Henky’s strain) of mixed gels were seen to increase with the increase in WPI and ECG concentration, thus revealing a higher solid character. This behaviour was consistent with a reduced pore size and increased opacity index of the gel matrix. Microstructure of WPI/ECG mixed gels revealed the existence of a biomacromolecule segregative phenomenon which could promote a greater local protein concentration in separated microdomains.