Impact of divalent salts and bovine gelatin on gel properties of phosphorylated gelatin from the skin of unicorn leatherjacket

•CaCl2 addition increased the gel strength of gelatin from the skin of unicorn leatherjacket more effectively than ZnCl2.•CaCl2 (20 μmol L−1) could strengthen the gel of phosphorylated gelatin (PFG) from the skin of unicorn leatherjacket.•The mixture of PFG and bovine gelatin (1:3) had the gel properties equivalent to bovine gelatin.

The impact of zinc chloride (ZnCl2) and calcium chloride (CaCl2) as well as bovine gelatin (BG) on the gel strength of phosphorylated fish gelatin (PFG) from the skin of unicorn leatherjacket was investigated. The gel strength of PFG increased with increasing concentrations of ZnCl2 and CaCl2 (2.5-40 μmol L−1). A higher gel strength was observed with CaCl2, compared with ZnCl2. The gel strength of PFG with 20 μmol L−1 CaCl2 increased by 15.7%, compared to the control gel. Nevertheless, at higher concentration (40 μmol L−1) of both salts, gel strength of PFG decreased. Hardness of gels decreased with increasing PFG content (P < 0.05). Nevertheless, no differences in hardness were found amongst gels with BG/PFG ratios of 4:0 and 3:1 (P ≥ 0.05). Thus, PFG could be used in combination with CaCl2 to substitute for BG at a level of 25%.