Development of a novel sugar-free functional beverage containing pistachio green hull extract

This study aimed to develop a novel phenolic-rich functional beverage utilizing pistachio green hull extract (PGHE) and to evaluate its physicochemical and sensory properties. An acute oral toxicity evaluation demonstrated that LD50 of extract is greater than 5000 mg/kg body weight of Wistar rats. The optimized formulation of the functional beverage was determined using response surface methodology (RSM). Different concentrations of PGHE, stevia, mannitol, and vanilla, along with constant concentrations of Arabic gum (0.5 % w/v) and ascorbic acid (0.04 % w/v), were used to prepare pistachio green hull based beverages. Total phenolic content (TPC) and IC50 were considered as dependent variables. The optimized formulation, based on maximum TPC and antioxidant activity, was identified, and sensory results indicated that functional beverage 1 (FB1, containing 8.0 % PGHE, 0.18 % stevia, 2.0 % mannitol, and 0.39 % w/v vanilla) is the best formulation. The FB1 showed L*= 14.83 ± 0.19, a*= 1.53 ± 0.05, b*= 12.45 ± 0.10, pH= 4.63 ± 0.01, and °Brix= 11.95 ± 0.07. To enhance the marketability of the optimized functional beverage, the concentration of PGHE and the flavor type were changed. Sensory evaluation of prepared formulations showed that functional beverage A (FB-A, containing 2.0 % w/v PGHE and 2.0 %v/v saffron extract) is more acceptable. The stability assessment of the optimized formulation, FB1, during two months of storage (4 °C) showed that TPC and IC50 remained unchanged. Overall, FB1 formulation has the potential to serve as a beneficial nutraceutical beverage, harnessing the health-promoting effects of all its ingredients, particularly PGHE.