Characteristics and gelling property of phosphorylated gelatin from the skin of unicorn leatherjacket

The characteristics and gelling property of gelatin from the skin of unicorn leatherjacket, phosphorylated with sodium tripolyphosphate (STPP) at various concentrations (0.25%, 0.50%, 0.75% and 1.00% w/w), for different times (1 and 3 h) at 65 °C, were studied. With the increase of STPP concentration and time, no increase in bound phosphate was observed. The highest gel strength was obtained for gelatin phosphorylated using 0.25% STPP for 1 h (P < 0.05). When the effect of pH (5, 7, 9 and 11) on phosphorylation and gel property of gelatin was investigated, gelatin phosphorylated at pH 9 had the highest gel strength (204.3 g) (P < 0.05) and exhibited a finer and more compact network structure with smaller pores. Gelatin became negatively charged (−3.89 mV) and might undergo an ionic interaction to a higher extent, thereby strengthening the gel network. Thus, the phosphorylation, under the appropriate condition, could improve the gelling property of gelatin from the skin of unicorn leatherjacket.