Optimization and characterization of an extruded snack based on taro flour (Colocasia esculenta L.) enriched with mango pulp (Mangifera indica L.).

The aim of this study was to optimize and characterize an extruded snack made with taro flour and mango pulp. A central experimental design composed of the following three variables was used: mango pulp proportion (MPP = 0-10 g/100 g) in taro flour, feed moisture content (FMC = 16-30 g/100 g) and extrusion temperature (zone 4 of extruder) (T = 80-150 °C) using a single-screw extruder with a compression screw ratio of 3:1. Increasing FMC values decreased the torque, pressure, specific mechanical energy (SME), expansion index (EI), water solubility index and pH values and increased the residence time, bulk density (BD), hardness and total colour difference. Increasing T values led to a decrease in the torque, pressure, BD and hardness values, while increasing MPP values only caused a significant increase in the hardness values and β-carotene content and a decrease in the pressure value. The optimal extrusion conditions were T = 135.81 °C, FMC = 18.84 g/100 g and MPP = 7.97 g/100 g, with a desirability value of 0.772, to obtain a snack with EI = 1.52, BD = 0.66 g/cm3, hardness = 24.48 N, β-carotene content = 99.1 μg/g and SME = 428.54 J/g. The mango pulp is an available and economical source of β-carotene for the enrichment of extruded expanded taro snacks.