The effect of polysaccharides on the ability of whey protein gels to either store or dissipate energy upon mechanical deformation

Abstract

The addition of polysaccharides to proteins during gel formation can alter the mechanical and textural properties of the resultant gels. However, the effect of addition of different polymers on mechanical properties of whey protein (WP) gels including their ability to elastically store energy, often measured in terms of the recoverable energy (RE), or dissipate energy, has not been fully reported. In this paper heat-induced WP gels containing high (HM) or low (LM) methylated negatively charged pectin or the neutral pullulan were prepared to study how the addition of polysaccharides to WP affects the mechanical properties of the formed gels. These gels were subjected to uniaxial compression and mechanical properties, including RE, were evaluated. The addition of pullulan to WP did not enhance the RE, whereas an increase in LM pectin resulted in higher RE. For gels containing HM pectin, the presence of the polymer induced an initial decrease of the RE. Nevertheless, RE increased with further increase in pectin concentration. These findings indicate that the addition of polysaccharides to whey proteins during gel formation results in changes in the RE but to different extent for different polymers. The results from this study suggest that the addition of polysaccharides to WP can be used as a tool to modulate the ability of whey protein gels to elastically store energy upon mechanical deformation.