Microstructural and textural properties of puffed snack prepared from partially deffated almond powder and corn flour

Abstract

Expanded snack was prepared from partially defatted almond powder (PDAP) and corn flour (CF). Response surface methodology (RSM)was used to investigate the effects of extrusion conditions including feed moisture content (12–16%), screw rate (120–220 rpm) and different levels of PDAP (10–30%) on expansion ratio (ER), bulk density (BD), hardness, complexing index (CI), and scanning electron microscopy (SEM) properties of expanded product. Results showed that increasing PDAP content caused an increase in the hardness, BD and thickness of a cell wall and a decrease in air cell diameter and ER of the snacks. Moisture content was the most significant parameter in all extrudates, therefore increased feed moisture leads to a lower density, hardness, CI and higher expansion, whereas the increasing screw rate caused reduction of bulk density and hardness of the extrudate. Optimum condition was found to be the blends of PDAP:CF (21:79), screw rate of 219 rpm and feed moisture content of 16%. Practical applications Global demand for production of high-nutritional snack with enhanced bioactive compounds has intended researchers towards fortification of traditional extrudates with bioactive components. Although cereal is the primary ingredient in expanded snacks, they contain less protein. So, incorporation of partially defatted almond powder not only can enhance the nutritional value of these products but also significantly impacts the texture and microstructural properties of products. Any change in the extrusion condition and feed formulation can influence the physical properties of the extrudate and it is necessary to optimize the processing conditions (feed moisture content and screw rate) for achieving the acceptable product properties. The main goal of this study was developing a value-added puffed snack with acceptable quality characterization.