Effects of Soaking, Roasting, and Germination on Saponin Reduction and Nutritional Enhancement in Quinoa ( Chenopodium quinoa )

This study evaluates the impact of soaking, roasting, and germination—alone and in combination—on saponin reduction and nutritional enhancement in quinoa ( Chenopodium quinoa Willd), integrating both biochemical analysis and engineering metrics for industrial scalability. Commercial quinoa seeds were subjected to controlled soaking (12–24 h, 3:1–5:1 v / w , 22°C, gentle agitation), roasting (180 ° C ± 2 ° C, 3.5 min, rotary drum roaster), germination (72 h, 25°C, 90% RH), and their sequential combinations. Proximate composition (AOAC methods), saponin content (gravimetric assay), and total phenolic content (Folin–Ciocalteu assay) were determined, with all measurements conducted in triplicate. Statistical analysis employed one‐way ANOVA to assess significant differences among treatments ( p < 0.05). Results demonstrated germination and combined germination–roasting as the most effective treatments, achieving a saponin reduction of 53% (0.56 ± 0.02 g/100 g vs. raw 1.20 ± 0.05 g/100 g, F = 238.88, p = 0.0001), the highest protein content (17.40 % ± 0.03 % vs. raw 14.73 % ± 0.61 % , p = 0.012), and total phenolic content (2.01 ± 0.18 mg GAE/g, 65% increase, F = 30.18, p = 0.00001). Roasting alone most effectively reduced moisture (3.57 % ± 0.16 % ), supporting shelf stability, but caused notable thermal degradation of phenolics (−48%). Engineering assessments revealed roasting as the most energy‐intensive step (1.2 kWh/kg), whereas soaking presented a throughput bottleneck (12–24 h, 8–16 kg/h). The findings suggest a scalable, integrated processing strategy combining biological and thermal treatments, optimizing nutritional value, antinutritional factor removal, and industrial feasibility for broader quinoa utilization.