Comparing conventional and novel extraction methods for chia seed mucilage as a sustainable vegan thickening agent†

Chia seed mucilage (CSM) is a remarkable food hydrocolloid with exceptional functional properties. However, variations in extraction conditions across studies impede reliable comparisons of CSM quality. This study investigates the influence of extraction conditions on the yield, physical properties, and functional properties of non-purified CSM. Three extraction methods – regular soaking (R), hot water soaking (H), and microwave-assisted (M) – were evaluated, with R serving as the control. The H method produced the highest yield (8.45 ± 0.22%), followed by M (5.76 ± 0.42%) and R (5.23 ± 0.21%). The CSM extracted via H yielded a darker colour and stronger tint than R and M's milky-white appearance. Regarding moisture content, R had the highest content (10.02 ± 0.82%), followed by M (8.4 ± 0.82%) and H (6.33 ± 0.42%). All samples displayed shear-thinning flow behaviour and viscoelastic properties, with M and H showing similar viscosity, while R demonstrated higher viscosity than both. The water holding capacity of H (117.03 ± 2.31 g g⁻¹) and M (108.28 ± 1.37 g g⁻¹) was significantly lower than that of R (152.88 ± 5.48 g g⁻¹). The oil holding capacity varied significantly among R (29.32 ± 1.11 g g⁻¹), H (18.15 ± 0.09 g g⁻¹), and M (25.61 ± 0.8 g g⁻¹). The emulsion capacity of R (91.74 ± 2.42%) was significantly higher than those of H (85.4 ± 2.54%) and M (92.97 ± 1.72%). Microwave-based CSM has shown the highest emulsion stability (96.71 ± 0.58%), followed by R (93.25 ± 0.46%) and H (92.97 ± 1.72%). The solubility of CSM did not differ significantly among the methods (78.1–82.48%). In conclusion, our findings emphasize the significant impact of extraction methods on the overall quality of CSM.