Stabilization of Whey Protein Isolate−Pectin Complexes by Heat

Protein−polysaccharide complexes formed under electrostatic associative conditions could have interesting functional properties. However, their stability over a wide range of pH limits their widespread application. The aim of this work was to determine the time−temperature combination required to stabilize whey protein isolate (WPI) and pectin (LMP) complexes formed at pH 4.5 to a further pH adjustment to 7. The effect of storage for 28 days at 4 °C was also evaluated. Stability was confirmed by quantification of sugar and nitrogen in each phase after centrifugation. Three heat treatments were performed: 73 °C/5 min, 85 °C/15 min, and 90 °C/2 min. At 73 °C/5 min, adjustment to neutral pH led to disruption of WPI−LMP complexes. The most severe heating conditions (85 and 90 °C) allowed the stabilization of WPI−LMP complexes. Heated complexes (90 °C) could be preserved for up to 28 days of storage at 4 °C without affecting their stability.