From raw material to functional food: Effect of dry-heat treatment on whole quinoa flour structure and dough rheology, with in vivo hypoglycemic validation at the optimal temperature.

This study investigated the effects of dry-heat treatment (DHT) temperature on whole quinoa flour structure, dough rheology, bread texture, starch digestibility, and hypoglycemic potential in STZ-induced diabetic mice. DHT induced surface aggregate detachment and imperfections on flour particles, while preserving the A-type starch crystallinity. Compared to untreated controls, DHT (110-150 °C) increased dough water absorption and softening degree, but decreased extensibility and resistance. Bread made with 110 °C-treated flour showed a slight decrease in hardness and a significant improvement in springiness; higher temperatures progressively deteriorated the texture. DHT notably lowered rapidly digestible starch and elevated slowly digestible and resistant starch fractions. Based on these in vitro results, 110 °C was identified as the optimal temperature, and only the 110 °C-treated flour was used for in vivo evaluation. In STZ-induced diabetic mice, six-week quinoa bread supplementation suggested beneficial effects on glycated hemoglobin, blood glucose, and insulin levels. These findings provide a theoretical basis for designing quinoa-based functional foods.