Extruded puffed functional ingredient with oat bran and soy flour

Extrusion cooking is a food processing technique that is used worldwide to transform various ingredients. The aim of this work was to apply extrusion to develop a functional puffed ingredient with defatted soy flour and oat bran and the minimum amount of corn starch required to attain good textural properties. The proportions of the feed ingredients and the processing conditions (extruder temperature, moisture, and inulin percentage as a technological coadjutant) were optimized. Applying mixture experimental design to study the effect of feed ingredients on expansion and textural properties of extruded product, the formula containing 250 g/kg corn starch, 375 g/kg soy flour, and 375 g/kg oat bran was selected as the best between tested. Using this blend and applying incomplete factorial design, the best process conditions (250 g/kg moisture; 45 g/kg inulin and 130 °C) were chosen. Based on the results of the process, optimization step temperatures higher than 130 °C were tested and showed that 160 °C increased the radial expansion ratio and decreased hardness the most. The obtained puffed product had 212.6 g/kg fiber, 281.0 g/kg protein, and a caloric value of 319.1 kcal/100 g. It was well accepted by the panelists in the sensory evaluation, mainly in terms of texture.