Effect of pH and hydrocolloids on the thermal stability of whey proteins in model beverage system

Abstract

In the preparation of whey-based beverages denatured whey proteins adversely affect the aesthetic quality of product. It was envisaged to stabilize cheese-whey and paneer-whey beverage systems at different adjusted pH (3.5-4.5) using hydrocolloids such as carboxymethyl cellulose (CMC), pectin, guargum and carrageenan at 0.1 to 0.25% levels. All the stabilizers had a significant (p<0.01, CD-0.061) influence on stabilization of whey proteins. CMC at 0.15% level and pH of 3.5 afforded maximum stabilization of cheese-whey proteins whereas, 0.25% of CMC at pH 3.5 exerted maximum stabilization to paneer-whey proteins. The stabilization effect of stabilizer on whey system was maximum at pH 3.5, which decreased with increase in pH to 4.5. Carrageenan (0.2%) at pH 4.5 and 0.1% carrageenan at pH 4.5 afforded least stability to cheese and paneer-whey systems, respectively. The stabilizing effect of stabilizer usually showed progressive increase with increase in the level of addition from 0.1 to 0.2%; at 0.25% level carrageenan and pectin showed maximum stability. Guargum, however, did not show a specific trend. The overall sensory score of both the whey systems containing stabilizers decreased in the order: CMC, pectin, guargum and carrageenan. CMC at 0.15-0.25% level and pH of 3.5 successfully stabilizes cheese and paneer-whey systems.