Creating novel food textures: Modifying rheology of starch granule suspensions by cold-set whey protein gelation

- Heat-denatured whey proteins in starch suspensions gelled by calcium addition.
- Viscous or paste-like materials were formed after cold-set gelation.
- Swollen starch granules modified the structure and rheology of these systems.
- These materials may be useful for reduced calorie food products.

There is increasing interest in creating novel structures in food products so as to create desirable textural characteristics. Cold-set gelation of pre-heated (90 °C/10 min) whey protein isolate (WPI) solutions (2.5, 5.0 and 10.0 g/100 g) and WPI-starch mixtures (2.5 g/100 g and 3.75 g/100 g, respectively) were initiated with calcium chloride (10 and 20 mmol/L). Calcium addition promoted gelation of the pre-heated systems at ambient temperature and led to increased turbidity, complex shear modulus (G*), and optical lightness. These measured properties increased with increasing protein and/or calcium concentration, which was attributed to more extensive protein network formation. In the WPI-starch mixed systems, the presence of swollen starch granules caused discontinuous protein network formation and led to lower gelation kinetics in comparison to protein-only WPI gels. Our results have useful implications for the formulation of semi-solid food products with specific rheological properties, i.e., gel-like or paste-like characteristics.