The Effect of Extrusion Conditions on the Physicochemical Properties and Sensory Characteristics of Fish‐Based Expanded Snacks

Expanded products with fish flour, rice and corn flour was prepared using a twin‐screw extruder with varying temperature, screw speed, total moisture and fish flour content to establish their effect on the expansion ratio, bulk density, porosity and water solubility index of the extrudates adopting response surface methodology. The experiments were optimized using five‐level, four‐factor central composite design. Analysis of variance was carried to study the effects of main factors and interaction effects of various factors and multiple regression analysis was carried out to explain the variability. Sensory acceptability study was conducted to select best products. The expanded materials obtained at 100–110C with feed material containing 15–20% fish flour and 14–18% moisture had the best properties. The study showed that expanded products produced using rice, corn and fish flour under conditions that induced the maximum expansion had the best acceptability. PRACTICAL APPLICATIONS: In the recent time, extruded products are gaining wide popularity. Most of the extruded snacks are cereal‐based and thus have less protein content and are limited in some essential amino acids. The incorporation of protein‐rich fish mince or fish flour would increase the nutritive value of such products. Fish mince or fish flour blended with rice/corn flour can be coextruded to obtain a nutritious snack without compromising the quality of the final product. Fish, which lacks good market in fresh condition, can be easily utilized for this purpose either by mincing or making fish flour. This study primarily aimed at preparing extruded snack‐like products using rice and corn flour with added flour from freshwater fish. Response surface methodology was applied to investigate the different process conditions on the physicochemical and sensory qualities of the final products.