Development, Characterization, and Statistical Evaluation of Functional Snacks Based on Microalgae, Quinoa, and Lucuma Using Extrusion Processes

This study evaluated the effect of twin-screw extrusion parameters on the nutritional, physical, and in vitro antioxidant properties of functional snacks formulated with quinoa, lucuma, and spirulina flours. A fractional factorial design (24−1) was applied to analyze the influence of screw speed (160–300 rpm), feed rate (1.6–4 kg/h), feed moisture (13–17%), and raw material composition on product quality. The results show that certain treatments, specifically T3 (screw speed of 300 rpm, feed rate of 1.6 kg/h, and moisture content of 13%) and T7 (screw speed of 300 rpm, feed rate of 1.6 kg/h, and moisture content of 17%), increase total phenol content, tannins, and antioxidant capacity, attributed to the low feed rate and high screw speed. In addition, it was observed that the expansion, solubility, and water absorption capacity properties are influenced by the extrusion conditions, affecting the texture. The mathematical model indicates that high feed rate, screw speed, and low moisture maximize the protein yield. The research shows that, among the eight treatments carried out with the split factorial design, treatment T4 (screw speed of 300 rpm, feed rate of 4 kg/h, and moisture content of 13%) showed the highest protein preservation (9.45 g/100 g) and antioxidant capacity (11.67 μmol ET/100 g), with moderate solubility and absorption capacity indices, allowing good product stability and reduced cracking during storage.