Development of high protein extruded snack using composite flour and milk proteins through response surface methodology

With the benefits of protein and relative retention of nutrition over other fried snacks, this study was used to formulate crunchy snacks using composites of rennet casein (RC), barley flour (BF), sweet potato flour (SPF), and rice flour (RF) with emphasis on protein. Central Composite Rotatable Design (CCRD) of Response Surface Methodology (RSM) was utilized to study the combined effects of SPF (20-35), BF (15-30), RF (30-40), and RC (10-30); all being in parts; on Water Absorption and Solubility Indices, L*, a*, and b* values, and Sensory attributes (flavor, color & appearance, texture, and overall acceptability) on the formulated composite extruded snack. An optimized product with carbohydrate, fat, protein, fiber, and beta-glucan (each 57.21%, 6.73%, 24.30%, 3.89%, and 2.16 mg/100 g, respectively), was reached with desirability quotient of 0.894. RSM was found to be a useful optimization tool for the formulation, also study the effect of ingredients. Practical applications The purpose of the present study was to develop and optimize nutritionally enriched extruded snack formulation using composite flour (barley, rice, and sweet potato) and milk protein (casein). It further aims to study the effect of these ingredients on the physicochemical and sensory properties and instrument color characteristics of the product. The formulated product was rich in protein, beta-carotene, beta-glucan, and minerals due to the pooled benefits of casein, barley, and high carotene sweet potato, thus making it an alternative nutritious functional product compared to other complementary snacks.