Heat-Induced Changes in κ-Carrageenan-Containing Chocolate-Flavoured Milk Protein Concentrate Suspensions under Controlled Shearing
2023
Anushka Mediwaththe | Thom Huppertz | Jayani Chandrapala | Todor Vasiljevic
Milk protein dispersions containing added cocoa powder (1.5% (w/w)) and sucrose (7% (w/w)) and varying levels of &kappa:-carrageenan (0.01, 0.03, or 0.05% w/w) were subjected to combined heat treatment (90 °:C/5 min or 121 °:C/2.6 min) and shear (100 or 1000 s&minus:1) to investigate the heat stability of milk proteins. The application of shear led to a notable reduction in non-sedimentable proteins, resulting in an increase in the average particle size and apparent viscosity of the dispersions, particularly at high concentrations of k-carrageenan and elevated temperatures. This indicates that shear forces induced prominent protein aggregation, especially at higher &kappa:-carrageenan concentrations. This aggregation was primarily attributed to the destabilisation of micelles and presence of loosely bound caseins within the &kappa:-carrageenan network, which exhibited increased susceptibility to aggregation as collision frequencies increased due to shear.
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