Application of fish skin collagen has received increasing attention due to mammalian derived diseases and religious limitations. Collagen fibril gel could be formed in vitro through the self‐assembly process. The present study investigated the effect of pH on the self‐assembly in vitro of acid‐solubilized collagen (ASC) from golden pompano skin by determining the turbidity, rheological viscoelasticity, network structure, gel strength, and thermal stability of collagen fibril gel.

The isoelectric point of ASC was pH 5.27. The turbidity–time and rheological viscoelasticity results indicate that the collagen self‐assembly rate in vitro at pH 7.0 was the slowest. The rate was accelerated by increasing or decreasing the pH. Scanning electron microscopy images show that the fibril diameters of the collagen fibril gels and the collagenous fibril number in the collagen fiber increased with the pH. The gel strength of the collagen fibril gel prepared at pH 5.0 was 22.06 g and increased up to 220.46 g when pH increased to 8.0. No obvious peaks were observed in the differential scanning calorimetry curves of the collagen fibril gels prepared at pH 5.0, whereas high endothermic peak temperature (T_m) and enthalpy change (ΔH) were found in the collagen fibril gels prepared at pH 6.0–8.0.

It is concluded that the physical properties of ASC fibril gels can be improved by increasing the fibril diameter controlled by pH. © 2020 Society of Chemical Industry