2.5.4. Rheological Analyses

Oscillatory shear measurements were performed on a Bohlin CVO rheometer (Bohlin Instruments Ltd., Gloucestershire, UK) using a cone-plate geometry (4◦ angle, 40 mm diameter, 0.15 mm gap). The temperature in the lower plate was 5 ◦C. Frequency sweep tests were carried out over a range of angular frequencies between 0.63 and 63 rad/s with an oscillation strain of 5%, selected from the linear viscoelastic region (LVER). The storage modulus (*G* ) and loss modulus (*G*) were plotted as a function of angular frequency (ω).

To understand the viscoelastic properties of the different yogurts, flow and viscoelastic properties of the additive aqueous suspensions were examined. Thus, three aqueous suspensions at the same concentration (1.5% *w*/*v*) were prepared: maltodextrin (MD), free hydrolysate (H), and microencapsulated hydrolysate (HEn). For determining the viscoelastic moduli, time sweeps at 20 ◦C for 1800 s at 0.05 Hz and small stress (σ = 1.5 Pa) were performed to minimize structural changes.

Flows were characterized by the step test, with three intervals starting with a preshear interval to homogenize the suspensions (100 s−<sup>1</sup> for 300 s). The three steps were: (1) reference interval (150 s−<sup>1</sup> for 90 s); (2) high shear-rate interval (1000 s−<sup>1</sup> for 45 s) to damage the internal structure; (3) regeneration interval (150 s−1, 600 s) at 20 ◦C. Each rheological test was repeated five times.
