Temperature-driven changes in physicochemical quality, antioxidant capacity, and technological properties of whole millet flour during storage

Millet is an ancient cereal of great importance for food and nutritional security with diverse applications. Among its derivatives, whole gluten-free millet flour stands out. Therefore, the objective of this study is to investigate the effect of time and storage conditions on the physicochemical and technological properties, antioxidant activity, and total phenolic compounds of whole millet flour. The experiment was conducted in a factorial design (2 × 5 × 3) with two storage conditions: one with control temperature (19.32 ± 0.39 °C) (CT) and the other uncontrolled temperature (28.85 ± 1.50 °C) (UT), five time periods (0, 3, 6, 9, 12 months), and three replicates. At each time point, analyses of proximate composition, pH, acidity, fatty acid profile, water and oil absorption capacities, water solubility, antioxidant activity by DPPH and ABTS methods, and total phenolic compounds were performed. Storage conditions did not affect the variables evaluated, except for water content, antioxidant activity, indicating that millet flour can be stored at 25–30 °C, thereby reducing transportation and storage costs. On the other hand, storage time significantly affected water, ash, protein, and lipid contents; pH; acidity; technological properties; antioxidant activity; and total phenolic compounds. During storage, there was a significant increase in phenolic content: 29.57% in UT flour and 47.41% in CT flour. Similar behavior was observed for antioxidant activity. However, technological properties were negatively influenced during storage.