Characterization of structural properties and non‐linear rheological behavior of collagen over a wide range of mass fractions under <scp>LAOS</scp>

Abstract In this study, large amplitude oscillation shear (LAOS) test was used to investigate the nonlinear behavior of collagen (COL) over a wide range of mass fractions. The original COL material is used in food industry with mass fraction of 7.6% (w/w) and another six mass fractions (1.5%, 2%, 3%, 4%, 5%, and 6%) were prepared by diluting. The structure of COL was evaluated via Fourier transform infrared spectroscopy and COL surface morphology was studied via scanning electron microscope (SEM). The results showed that the storage and the loss modulus increase with increasing COL mass fraction and COL showed a weak strain overshoot behavior. The Lissajous–Bowditch curves showed a gradual transition from narrow elliptical to wider elliptical shaped loops as the strain amplitude increases and the third‐order Fourier coefficients , values were changed significantly with the collagen mass fraction. The morphology results showed that dilution does not affect the internal structure of the COL gels. The results from this work are important since the nonlinear rheological response under LAOS of industrial collagen with a high mass fraction has not been reported. Highlights The viscoelasticity is tested and quantified for different mass fractions of COL. Tested COL is used in the food industry and has a high mass fraction (MF) The novelty for COL is in the combination of MF and evaluation methods. The structure of COL is evaluated via Fourier transform infrared spectroscopy. The surface morphology was studied via a scanning electron microscope.