Optimization of the Mechanical Isolation Process of Mucilage from Chia Seeds (Salvia hispanica L.): Physicochemical, Morphological, and Rheological Characterization

This study aimed to evaluate how hydration temperature, rotational speed, and screw restriction influence the extraction efficiency, physicochemical characteristics, and monosaccharide composition of chia seed mucilage (CSM). Optimal extraction conditions (43.7 Hz, 100% screw restriction and 50 °C) yielded an extraction efficiency of 65.69% and a mucilage yield of 7.66%, producing a material with an average particle size of 15.28 μm, a ζ-potential of 9.7 mV, and weak-gel rheological behavior. Structural analyses confirmed the absence of insoluble fiber and revealed crystalline phases including MgO, Ca5P8, K2S, K4P6, and CaCO3, along with typical polysaccharide functional groups (–OH, –CH, C=O, COO−, C–O). Moderate hydration temperature combined with controlled mechanical conditions favored the release of mucilage enriched in xylose, glucose, and arabinose, which are characteristic of seed coat polysaccharides. In contrast, minimal mechanical action or excessive seed disruption shifted the monosaccharide profile toward cell wall structural carbohydrates, indicating reduced mucilage purity. Elevated hydration temperature (75 °C) enhanced the solubilization of uronic acids and arabinose, suggesting increased extraction of acidic polysaccharide fractions associated with the seed coat matrix. These findings demonstrate that extraction parameters strongly determine CSM composition, structural integrity, and functional attributes. The results provide a basis for tailoring chia-derived polysaccharides for applications in hydrocolloid systems, bio-based materials, and functional polymer formulations.