Preparation of self-assembled collagen fibrillar gel from tilapia skin and its formation in presence of acidic polysaccharides

•Different acidic polysaccharides affect the properties of collagen fibrillar gels distinctly.•Gel with SA exhibited denser network while those with CS and HA depicted larger ordered structures.•Gelling time and enzymatic resistance are maintained with HA addition but compromised in gels with CS and SA.•Acidic polysaccharides can increase mechanical strength and d-periodicity of the gels. Fibrillar gel of pepsin-solubilized collagen from tilapia skin was prepared by self-assembly in neutral phosphate buffer at 28 °C. Then effects of acidic polysaccharides, such as sodium alginate (SA), chondroitin sulfate (CS), and hyaluronic acid (HA), on the formation and properties of self-assembled fibrillar gel were investigated. SA and CS prolonged gelling time, whereas HA had no obvious effect. SA made fibril network denser, while CS and HA induced the presence of larger ordered structures. All the acidic polysaccharides broadened the D-periodicity of fibrils. SA and HA increased the maximum mechanical strength of gel to 39.64 and 34.49 kN/m2, respectively, significantly higher than that of pure collagen gel (14.53 kN/m2), while that only 17.20 kN/m2 after CS introduced. HA had no evident effect on enzymatic resistance, while SA and CS decreased. Therefore, tilapia skin collagen with HA has a higher potential as a biomaterial than that with CS or SA.