Physico-chemical and rheological properties of sage seed gum extracted by dry method in comparison with the conventional method

This paper aimed to evaluate the chemical compositions, water absorption capacity (WAC), solubility, extraction yield, and steady shear rheological properties of sage seed gum (SSG) extracted by the dry method (DEM) in comparison with the SSG extracted by the conventional wet method (WEM). The chemical compositions (w.b.%) including moisture, ash, protein, fat, and carbohydrate of the gum extracted by DEM were 7.64, 4.11, 7.02, 10.41, and 68.74%, respectively, while the values using WEM were 7.51, 8.69, 3.21, 0.97 and 77.21%, respectively. The solubility and WAC were 41% and 72% in DEM, and 13.73%, and 18.32% in WEM, respectively. Rheological results showed that the best model to fit the time-dependent rheological data was the first-order stress decay model with a non-zero equilibrium stress value. Based on this model, the extent and rate of thixotropy were obtained as 0.042 and 0.0038 s-1 for the DEM-SSG sample and 0.048 and 0.0082 s-1 for the WEM-SSG sample, respectively. The time-independent shear-thinning behavior was described by the Herschel-Bulkley model with excellent correlation. Based on this model, the yield stress, consistency coefficient, and flow behavior index for the WEM-SSG were 3.82 Pa, 3.22 Pa.sn, and 0.41 while the relevant values for DEM-SSG were 1.07 Pa, 0.47 Pa.sn, and 0.56, respectively. According to the findings of this research, the dry extraction method can be used as a fast, single-stage, low energy consumption, cost-effective and environment-friendly process.