2.5. Characterization of Rheological Properties

The rheological properties determination was according to the method of Ren et al. [26], and steady shear and oscillatory frequency sweep determination was carried out by Discovery HR-10 rheometer system (TA Instrument, New Castle, DE, USA). The gap was set at 500 μm. The steady state shear scanning ranged from 0.1 s⁻¹ to 100 s⁻¹. Besides, the elastic modulus (G′) and viscous modulus (G″) were measured with fixed 0.1% strain, and frequency scanning ranged from 0.1–10 Hz in the dynamic rheological test [27,28]. The power law model is well-known for its extensively utilization in describing the flow properties of non-Newtonian liquids. The obtained rheological data were fitted to the power law model (Equations (1)–(3)) to investigate the variation in the rheological properties of set yoghurts added with different polysaccharides under steady shear and oscillatory sweep.

In Equations (1)–(3), η, G′, and G″ represent the apparent viscosity (Pa·s), elastic modulus (Pa), and viscous modulus (Pa), respectively. K, K′, and K″ represent the consistency index, while γ and f represent the shear rate (s⁻¹) and frequency (Hz), respectively. The n, n′, and n″ all represent the flow behavior index (dimensionless). The apparent viscosity (η), elastic modulus (G′), viscous modulus (G″), and loss tangent (tanθ = G″/G′) were obtained by TA rheometer data analysis software.