Formula optimization of a low-fat food system containing whey protein isolate-xanthan gum complexes as fat replacer

Whey protein isolate-xanthan gum complexes (WPXC) have the potential to significantly reduce fat use in various products. However; their stability and functionality have not been extensively studied; particularly in neutral pH products. The objective of this study was to evaluate WPXC as a fat replacer in cake frostings and sandwich cookie fillings with reduced-fat content (160 or 80 g/kg fat); Response surface methodology was used to analyze the effect of WPXC on the viscosity and textural response attributes of samples and to optimize the low-fat formulations: It was found that WPXC had a positive effect (P > 0.001), providing acceptable viscosity and texture attributes to the low-fat samples. A significant moisture-WPXC interaction (P > 0.001) revealed that the optimum moisture-WPXC ratio varied, depending on the targeted texture. This ratio was about 8:1 for cake frostings and about 5:1 for sandwich cookie fillings. Optimal formulations were,found; and samples meeting the desirability specifications presented textural and melting profiles similar to those of the control products: However, for the production of sandwich cookie fillings; the use of other ingredients (for example humectants and emulsifiers) must be considered to maintain a low water activity (A(w)) and prevent moisture migration to the cookie shell.