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

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 (109.2 C ), 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/cm 3 ; 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.