The effect of three fat replacers (xanthan gum, Reihan seed gum, and Balangu seed gum) and two sweeteners (sucrose and isomalt) on time-dependent rheological properties of low-calorie pistachio butter were analyzed using response surface methodology. The steady shear behavior of all samples was shear thinning (n = 0.156–0.6175), and power law model was fitted the upward and downward curves properly (R2 = 0.847–0.998). Balangu seed gum (0.01–0.04 wt.%), Reihan seed gum (0.01–0.023 wt.%), xanthan gum (0.06–0.1 wt.%), isomalt (0–1 wt.%), and sucrose (0.25–1 wt.%) were the levels investigated. A central composite design was used to develop models for the responses. The obtained experimental data were fitted to a second-order polynomial equation and also analyzed by appropriate statistical methods. In most cases, increasing the sweetener level led to a significant decrease in consistency coefficients. However, the effect on the flow behavior index was not significant. The effect of gum concentration on the rheological parameters was not significant (p ≤ 0.1), except for formulas prepared using Balangu seed gum. All formulas studied were stable on shelf.
