Utilizing Whey Protein Isolate and Polysaccharide Complexes to Stabilize Aerated Dairy Gels
Overrun of aerated gel (179% to 14%) significantly decreased as polysaccharide concentration increased due to increased viscosity which limited air incorporation. Increased concentration was significantly related to increased stability (P < 0.001) which could be due to increased viscosity of the pre-foam solutions limiting the mobility of the air bubbles. A negative logarithmic relationship was found between solution viscosity and drainage. However, charge density played an important role on stability. Plot of drainage against solution viscosity revealed that drainage was lowest in samples with high charge density pectin (LM-12) followed by those with low charge density pectin (HM-D). Aerated gels with guar gum (no charge) did not show improvement to stability as separation still occurred even at highest guar concentration. Rheological results showed no significant difference in gelation time among samples; therefore, stronger interactions between WPI and high charge density polysaccharide were likely responsible for increased stability. Rheological results also revealed that aerated gels with LM-12 pectin had the highest final elastic modulus, followed by guar gum, then HM pectin gels.
Stable dairy aerated gels can be created from WPI-polysaccharide complexes. High charge density polysaccharides, at concentrations that provide adequate viscosity, are needed to achieve stability while also maintaining solution overrun capabilities. This can inform the formulation of dairy-based gels set by acid or calcium such as whipped yogurts and mousses.
Keywords: acid-induced gelation, aeration, whey protein