Self-assembly characterization of tilapia skin collagen in simulated body fluid with different salt concentrations

Abstract

The characteristics and self-assembly properties of acid soluble collagen (ASC) from tilapia skin in simulated body fluid (SBF) with different NaCl concentrations were investigated. When the concentration of NaCl was 65 mM, the lag time in the turbidity of collagen fibril formation was 2 min, which increased with the NaCl concentration. However, the collagen fibril forming degree decreased with the increasing NaCl concentration. Gel strength decreased when NaCl concentration increased from 135 mM to 160 mM. Rheological and differential scanning calorimetric analyses showed that the elasticity, melting temperature (Tm), and enthalpy (ΔH) of collagen fibril gel were promoted by the increasing NaCl concentration. Self-assembly could affect the conformation but did not affect denaturation of collagen. The dense fibril network structure of collagen gels was formed at SBF with high NaCl concentration. No obvious change was found in the d-periodicities of assembled fibrils. The amide I, II, and III bands in the Fourier transform infrared spectra of collagen gel moved from 1633, 1538, and 1236 cm−1, respectively, to 1628, 1532, and 1229 cm−1, respectively with the increasing NaCl concentration. These results exhibit that the ASC can self-assemble to form different collagen fibril gels in the SBF by adjusting the NaCl concentration.