Haake mars modular advanced rheometer system

The chemical compositions of lyophilized CSBDX samples were analyzed by Fourier transform infrared (FTIR). Injectability property of the CSBDX was observed visually by loading the hydrogel into a 1 mL syringe and injecting it manually to write words ‘SYSU’. After minutes of gelation, photographs were taken. The self-healing property of the CSBDX was evaluated by cutting the hydrogel in half, one of which was colored by crystal violet, and simply put them together to ensure the cross-sections completely adhered. After 24 h at 37 ℃, the self-healing hydrogel was picked up by tweezer remaining intact. The self-healing interface of another piece of self-healing hydrogel was observed by stereomicroscope. Rheological continuous step strain test was performed to further reveal the self-healing behavior of CSBDX hydrogel. The CSBDX samples with a diameter of about 25 mm and a thickness of 1 mm were prepared and HAAKE MARS Modular Advanced Rheometer System (Thermo Scientific) was used to carry out continuous step strain test at 37 ℃. The parameters were set: angular frequency of 6.28 rad/s, strain 1% (duration 100 s) → 100% (100 s) → 1% (100 s) → 100% (100 s) → 1% (100 s).

Viscosity curves were carried out using a rotational rheometer Haake Mars Modular Advanced Rheometer System (Thermo Fisher Scientific, Massachusets, USA) associated with the refrigeration system (Peltier) Thermo Scientific Haake MarsIII Controller and to the air compression system Eheim professional 3. The PP60 probe (60 mm of diameter, rough surface) was used for the thick samples—puree, pomace, and snack/formulations—and the CC25 DIN Ti probe (concentric cylinders) was used for the other liquid samples. Viscosity curves were obtained in triplicate, with a 1.5 mm gap, at 20 ± 2°C, with shear rates ranging between 1 × 10⁻⁸ and 100 s⁻¹, stepping up every 35 s to ensure the steady-state on each shear rate. Data treatment was carried out using Origin 2019b (OriginLab) software, adjusting the obtained curves to the Cross model (Equation 4):
where η_∞ (Pa.s) is the infinite shear viscosity, η₀ (Pa.s) the zero-shear viscosity, k the consistency coefficient (Pa.s), m the Cross rate (dimensionless) constant, and ${\stackrel{\bullet }{\gamma }}^{.}$ The shear rate (s⁻¹).