Apparent Viscosity of a Skim Milk Based Dessert: Optimization Through Response Surface Methodology

In this study, the apparent viscosity of a skim milk based dessert was optimized through the use of a 5-level Central Composite Design. The effect of carrageenan, guar gum, sucrose and pH on the dessert's apparent viscosity was esti-mated. The dessert's flow behavior was also analyzed. A rotational viscometer was used for the the apparent viscosity measurements. All formulations presented a non-Newtonian, shear-thinning behavior. Except for carrageenan concentration, all of the design factors affected apparent viscosity, being the effects better described by second order polynomial models. The following combinations of the variable ingredients yielded the best apparent viscosity: guar gum concentration: 0.0-0.315% (w/w) and sucrose concentration: 5.000-8.615% (w/w); or guar gum concentration: 0.109-0.315% (w/w) and sucrose concentration: 5.000-11.000% (w/w); in both cases, carrageenan and pH were kept at 0.020% (w/w) and 6.50, respectively.