Fish Oil‐Fortified Extruded Snacks: Evaluation of Physical Properties and Oxidative Stability by Response Surface Methodology

Abstract

AbstractResponse surface methodology was employed to study the physical characteristics and oxidative stability of fish oil‐fortified extruded snack. Process temperature (80–140C), feed moisture (12–20%), screw speed (300–400 rpm) and fish oil content (0.5–2.5%) were selected as the independent variables at five levels. A central composite design was developed to study the linear, quadratic and interactive effect of the selected independent variables on responses studied viz. expansion ratio, porosity, hardness, crispness and thiobarbituric acid reactive substance values. The physical properties of extruded samples such as expansion ratio, porosity and crispness were mostly influenced by feed moisture followed by fish oil content. Fish oil showed significant interactive effect with temperature on expansion ratio and porosity. The product with fish oil content up to 0.8% was found significantly oxidatively stable and fish oil can therefore be added to improve the nutritive and functional value of extruded snacks.Practical ApplicationsThe more frequently consumed products like rice‐based extruded snack can be fortified with fish oil, a source of cardioprotective omega‐3 fatty acids without causing undesirable changes in the physical properties. Any change in the feed formulation can influence the physical properties of the extrudate and it is essential to optimize the processing conditions for achieving the acceptable product characteristics. The present study gives an account on the effect of fish oil fortification on the physical properties of an extruded snack. The results of the study will be useful for the food processors to decide on the optimum parameters for developing fish oil‐fortified extruded snack with acceptable product quality characteristics.