Impact of drying temperature on the physicochemical and functional properties of butterfly pea flower powder

Butterfly pea flower (BPF) powder, which is rich in bioactive compounds, was evaluated for the impact of various drying methods on its solubility, physical properties, and chemical composition. Four drying methods were used: thermal drying at 50 °C, 60 °C, 70 °C, and natural sun drying. The powders were assessed for solubility time, hygroscopicity, density, flowability, and chemical stability using scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR). Solubility times ranged from 148 to 162 s, with no significant differences. The 70 °C dried sample (Sample C) had the fastest dissolution rate and highest hygroscopicity. Total phenolic and anthocyanin contents increased with temperature, peaking in sun-dried samples (Sample D). Density measurements showed Sample C had the highest bulk density and optimal flowability, while Sample D had superior water holding capacity. The SEM analysis revealed morphological differences, with Sample A showing a smooth surface and Sample C exhibiting significant particle disintegration. The XRD analysis showed that Sample C had the highest crystallinity. The FTIR analysis confirmed the stability of key functional groups, with sun-dried samples retaining phenolic compounds. These findings suggest drying methods can optimize BPF powder’s properties, enhancing its bioactivity for health applications.