Process Optimization and Product Characterization of Tomato Pomace Incorporated Biofunctionalized Extruded Puffs: Effect of Extruder Operational Parameters

The effects of tomato pomace concentration, feed moisture, and screw speed on physicochemical and biofunctional attributes of tomato pomace-corn based extrudates was investigated. As tomato pomace concentration increased, expansion ratio and porosity of the extrudates decreased resulting in harder products. This effect of increased hardness, was mitigated by correspondingly increasing the moisture content. With increasing moisture content, porosity first increased and extrudate structure enhanced as shown by mean pore size but with further increase collapse of the extrudate immediately after exiting the extruder was observed. Screw speed positively impacted the crispness and the structure of the extrudate contributing to enhanced sensory properties moderating the impact of pomace addition. The formulation comprising of 14.39% tomato pomace concentration at a screw speed of 213 rpm and feed moisture of 13.44% was optimized and validated. The tomato pomace functionalized puffs had a higher protein (10.6%) and dietary fiber (15.19%) content compared to control (1.58% and 9.97%, respectively) as well as lycopene content of 0.54 mg/100 g. This process allows for inclusion fiber rich tomato pomace as a functional ingredient in corn based puffed extruded snack which are a healthier option than currently available extruded snack options.