Mars 60

The relative stiffness of collagen gels was measured using a MARS60 microinfrared rheometer (Thermo Fisher, MA, USA) under the following conditions. Briefly, the collagen gels were measured over a range from 0.5–5% strain at a fixed angular frequency of 0.5 rad/s and temperature of 21 °C on MARS60 microinfrared rheometer. The output of G’ was recorded for 20 min with a data point obtained every 60 s. The samples were found to be only minimally frequency dependent within the range of testing and showed a linear viscoelastic response within the strain range evaluated.

Before the test, the yoghurt sample was placed at room temperature for 15 min, and the apparent viscosity was measured by using haake rheometer (MARS 60, Thermo Fisher Scientific, American). The selected rotor model was P60/Ti-02150138. Fixture for the test plate (diameter 25 mm) test spacing of 500 μm, 1 ml of yoghurt sample was tested on the surface, and the excess samples were removed. Calibration was performed at 25°C for 1 min, with 30 points at 0.1–200 s⁻¹ shear rate (γ) for testing to create a dynamic viscosity curve.

The chemical structure of samples was studied by an FTIR (VERTEX 80 V, Bruker Optics Inc., Ettlingen, Germany) with the attenuated total reflectance (ATR) mode, an X‐ray diffraction spectrometer (XRD, Ultima IV, Rigaku Cor., Tokyo, Japan) with Cu Kα radiation at 40 kV and 30 mA, and a ThermoFisher Raman spectrometer (DXR532, Waltham, MA, USA) with a laser wavelength of 532 nm. The rheological properties of various film‐forming suspensions were measured using a rheometer (MARS60, Thermo Fisher Scientific Inc., Waltham, MA, USA) with a 20 mm diameter geometry and a 1° cone angle. The contents of elements and sulfate ions were analyzed by inductively coupled plasma mass spectrometer (ICP‐MS, NeXion 300X, PerkinElmer Inc., MA, USA) and ion chromatograph (ICS900, DIONEX Inc., Sunnyvale, CA, USA). The morphologies of samples were investigated by a field emission scanning electron microscopy (FESEM, Regulus 8100, Hitachi Co., Ltd., Tokyo, Japan) with an energy dispersive X‐ray spectroscopy (EDS) and a TEM (JEM‐1400, JEOL Ltd., Tokyo, Japan). The surface compositions and morphologies of zinc anodes were analyzed through an AXIS UltraDLD XPS (Shimadzu Cor., Berlin, Germany). In addition, a Bruker atomic force microscope (AFM, Dimension Edge, Tokyo, Japan) was employed to observe the surface and section morphologies of zinc anodes.

Dynamic rheological analysis was carried out with a rotary rheometer (Mars 60, Thermo Fisher Scientific, Karlsruhe, Germany) equipped with a parallel plate geometry and using 20 mm diameter plates. The samples with a thickness of 1.0 mm were melted at 235 °C in the fixture and then subjected to dynamic frequency sweep. The frequency sweep range was 0.1–628 rad/s, with a fixed strain of 1%.