Extraction of chia and okra mucilages: physicochemical characterization, bioactive compounds, and antioxidant activity, drying kinetics, and thermodynamic properties

The objective of this study was to extract mucilages from chia (CM) and okra (OM), followed by their comprehensive chemical and physicochemical characterization, assessment of bioactive compounds, and antioxidant activities. The mucilages were dried at temperatures (50, 60, and 70 °C), and their drying kinetics were analyzed using mathematical models, along with thermodynamic attributes. Mucilage extraction involved aqueous processing: material comminution with water, immersion, filtration, and subsequent ethanol-induced precipitation. Preceding drying, mucilages showed high water content and activity, reduced ascorbic acid and lipids. CM had high mineral and starch content, while OM displayed elevated proteins, phenolic compounds, tannins, anthocyanins, and flavonoids. OM exhibited superior antioxidant activity (ABTS, FRAP, and DPPH). Among the various mathematical models considered, the Diffusion Approximation model best fitted the experimental data for CM, while the Two-Term model yielded the optimal fit for OM. The effective diffusivity and activation energy for CM were determined to be approximately 10 −9 m 2 /s and 38.60 kJ/mol, respectively. Conversely, for OM, these values were calculated as 10 −8 m 2 /s and 17.21 kJ/mol, respectively. The thermodynamic characteristics of both drying processes indicated a non-spontaneous nature. This investigation divulged distinctive attributes of the mucilages derived from chia and okra, highlighting their potential utility as valuable raw materials within diverse industries, encompassing the realms of both food and pharmaceutical sectors.