Optimization of Fish Based Extruded Product by Twin Screw Extrusion using Response Surface Methodology and Shelf life Evaluation

Abstract

Effect of extrusion conditions like temperature,
screw speed, and moisture content of the fish
incorporated extruded snack on specific mechanical
energy (SME) and texture were evaluated and
optimized by using response surface methodology.
A central composite design with 20 runs was
formulated for the experiment and the quadratic
model was most suitable for explaining the changes
of dependent variables with respect to independent
variables. It was found that as the temperature
increased, SME and texture decreased; whereas,
SME was directly proportional with screw speed.
There was a decrease in the SME and increase in
texture as the moisture content increased. Maximum
desirability value of 0.873 revealed that the
screw speed of 380 rpm at a temperature of 140°C
and 17% moisture content were optimum for the
development of fish incorporated extruded snack
and values for SME and texture were
251.26 KJ kg-1 and 9.86 N, respectively. Storage study
of fish-incorporated extruded snack developed at
optimized conditions revealed that thiobarbituric
acid and texture were increased with storage period.
Similarly, redness of the sample increased while
whiteness and yellowness of the sample were
decreased with storage. At ambient temperature
(28±1°C), the product had a shelf life of 4 months.