Extrusion Cooking of Maize/Spirulina Mixture: Factors Affecting Expanded Product Characteristics and Sensory Quality

Abstract

The physical properties and sensory attributes of an extruded product are generally influenced by a large number of process and ingredient variables. Expansion is the most important physical property of the snack food. The effects of spirulina powder (SP) addition to maize flour (MF) on the physico-chemical and sensory quality of extrudates were investigated. Addition of SP (7.5%) in the MF blend increased the carotenoids, protein and zinc contents and produced crisp to hard-textured extruded products. The protein, zinc and carotenoid content of extruded product were respectively, 14.63%, 6.66 mg/Kg and 138.83 mg/kg. Optimum operating conditions for development of SP and MF blended extrudate were: barrel temperature (109.2C), screw speed (280 rpm) and feed moisture (16% d.b.). These optimum process conditions resulted lateral expansion of 161.46%, bulk density, 0.18 g/cm3; water absorption index, 6.22 g/g; and overall acceptability, 6.12 with desirability 0.809. Practical Applications Extruded food products produced from cereals are usually low in protein and have a poor biological value due to their limited essential amino acid contents and are often fortified with proteins. Spirulina – cyanobacteria has been used by different populations as protein source and other nutritional requirement. Successful incorporation of spirulina into cereal-based extruded products could deliver physiologically active components, represents a major opportunity for food processors who are engaged in providing the consumer a healthy maize-based product, which is currently lacking in the market place.