The Dynamic (Oscillatory) Rheological Properties of Imitation Pizza Cheese Containing Soy Protein Isolate as a Partial Caseinate Substitute

Increasing soy protein isolate content may be a practical and cost-effective means to control the functional properties of imitation pizza cheese. Imitation cheeses containing 2, 3 and 5% (w/w) soy protein isolate as a partial caseinate substitute were manufactured and dynamic rheology of these products were compared to a control (0% w/w soy protein isolate) in temperature sweep analysis. The dynamic rheological properties of caseinate-based imitation cheeses containing various concentrations of soy protein isolate were investigated using a strain-controlled rheometer. The storage modulus (G’), the loss modulus (G”) and the loss angle (Tan) were measured as a function of temperature (35–100°C). The storage modulus and loss modulus of imitation cheeses was significantly decreased (P0.05) at all examined temperatures (35–100) with the inclusion of soy protein isolate. Inclusion of soy protein isolate significantly increased imitation cheese peak Tan values compared to control (P0.05), and the inclusion of 5% (w/w) soy protein isolate as a partial caseinate substitute had the greatest effect. In sensory evaluation, in terms of texture and mouthfeel, flavour and total acceptance the highest score belonged to control, while in all of samples lowest score observed in sample containing 5% w/w soy protein isolate. The results of this study showed that varying the level of soy protein isolate altered dynamic rheological properties as a function of temperature and thus the functionality (for example, meltability), as well as sensory attributes of imitation pizza cheeses.