Extraction of fish oil from tuna scraps by dual enzymatic hydrolysis
Two proteinases were used to extract oil from fish scraps. The aim of this work was to investigate the effect of material-liquid ratio, enzyme addition and reaction time on the oil extraction yield after enzymatic hydrolysis of fish scraps. In addition, the oil extraction yield by freezing and thawing increased after enzymatic treatment and the condition of demulsification was optimized. The result showed that material-liquid ratio liquid was 1:3, the addition of proteinase A and B were both 1.5%, reaction time of proteinase A and B was 3 h and 2 h, respectively. Then the enzymatic hydrolysate was frozen at -20 ℃ for 12 h and thawed at 40 ℃ for 1.5 h for demulsification. Under these conditions, the oil extraction yield was up to (6.58±0.56)%, the physical and chemical properties of crude fish oil accorded with the second grade for SC/T 3502—2000.