ABSTRACT
Fish oil is an important nutrient component in rainbow trout bone, and the optimization of extraction by enzymatic hydrolytic method is of great significance.This study selected the alkaline protease as the hydrolytic enzyme, and optimized the process conditions of enzymatic hydrolysis of rainbow trout fish using single factor analysis method.Effects of several factors on the extraction of fish oil were studied, including the ratio of material to liquid, pH, enzymatic hydrolysis time, enzymatic hydrolysis temperature and amount of enzyme.Fatty acids were identified by gas chromatography-mass spectrometry (GC-MS).Results showed that the optimum extraction parameters of enzymatic hydrolysis were as follows: 2000 U/g alkaline protease, ratio of material to liquid of 1∶1 (w/w), pH 7.5, and extraction at 55℃ for 3h.It was found that the main composition of rainbow trout bone oil was unsaturated fatty acid with the content of 80.4% (w/w).The relative content of monounsaturated fatty acid and polyunsaturated fatty acid was about 76.9% (w/w) and 23.1% (w/w), respectively.The total content of EPA and DHA was 3.4% (w/w).This study optimized the extraction method of rainbow trout fish oil, analyzed and identified the main volatile compounds, and identified the main substances contributing to fish oil flavor.The method thus was of significance for the analysis and identification of fish oil products.