Development of a third-generation snack with type 4 resistant sorghum starch: Physicochemical and sensorial properties

Abstract

Extruded third-generation fiber enriched snacks can be made using type 4 resistant starch. The present study aimed to evaluate and optimize some extrusion conditions, namely the transition or intermediate barrel temperature and the feed moisture in the direct formation of third-generation snacks with type 4 resistant starch using the phosphorylation of sorghum starch. The physicochemical and sensory properties of the optimal snack were investigated. An increase in barrel temperature resulted in an increase in the resistant starch (13.1 ± 0.5 g/100 g) and the expansion index values, as long as the feed moisture was maintained above 28%. The optimal conditions with a desirability value of 0.932 were a barrel temperature of 136 °C and a feed moisture of 28.5%. The optimal third-generation snack had 17.1 ± 0.2 g/100 g of resistant starch and a desirable expansion index of 5.7 ± 0.4, as well as general sensory acceptability (“I like moderately”). Phosphorylated resistant starch of the optimal snack showed a degree of substitution and a percentage of phosphorus (0.02 ± 0.00 and 0.35 ± 0.15%, respectively) within the limits allowed in foods. This study showed that using optimal extrusion conditions, phosphorylation of sorghum starch was possible to produce resistant starch and simultaneously to obtain an extruded snack with acceptable physical and sensorial properties. Additionally, it showed that sorghum is a good alternative source of starch for the formulation of extruded snacks.