Steady Shear Rheological Behavior and Thixotropy of Low-Calorie Pistachio Butter

Abstract

Stressing the importance of diet in the prevention of certain diseases, nutritional scientists have emphasized on the reduction of calories in consumers diets. The steady-shear flow behavior of three optimized low-calorie pistachio butter formulations containing fat replacers (xanthan gum, Reihan seed gum, and Balangu seed gum) and sweeteners (sucrose and isomalt) were investigated at different temperatures. All three samples presented a non-Newtonian shear thinning flow behavior. Bingham, power law, and Moore models were selected as the appropriate time-independent rheological ones. Increasing the temperature resulted in lower values of Bingham viscosity, Bingham yield stress, and consistency coefficient. Increasing the amount of pistachio paste and isomalt led to higher and lower viscosity values, respectively. All data were reasonably fitted by Arrhenius model and formula containing xanthan gum showed the highest temperature dependency. The structural recovery evaluation revealed a weak thixotropic behavior for all samples.