Resolving the problem of poor expansion in corn extrudates enriched with food industry by-products

Abstract

Abstract The aim of this study was to investigate the possibility of application of brewer's spent grain (BSG), sugar beet pulp (SBP) and apple pomace (AP) in production of corn snack products. Additionally, in the case of BSG and SBP the pectin (0.5% and 1% d. m.) was added in an attempt to resolve the problems of poor expansion and textural properties. Samples were extruded in the laboratory single screw extruder, and physical and sensory properties of obtained extrudates were determined. By-products addition decreased expansion ratio and fracturability, whereas bulk density and hardness increased. Pectin addition at level of 1% resolved the problem of poor expansion in the extrudates with BSG and SBP, which resulted in successful incorporation of all three by-products in the production of acceptable expanded corn snack products. By-products addition and extrusion process had a significant effect on color change, water absorption and water solubility indexes. Industrial relevance The production of nutritionally fortified snack products, with the acceptable physical and sensory properties is challenging. The addition of high-fibre and high-protein ingredients to starch based raw materials significantly affects the texture, expansion and overall acceptability of extruded snacks. This study provided a novel and effective way to resolve these problems in production of corn extrudates enriched with food industry by-products, by pectin addition. Furthermore, this investigation could partially help in the disposal of waste from the food industries in which the investigated by-products (brewer's spent grain, sugar beet pulp and apple pomace) are formed in large quantities.