Abstract:In order to realize high-value utilization of poultry blood，heme was extracted by protease hydrolysis of chicken blood hemoglobin.To determine the most appropriate protease，the degrees of hydrolysis of 3 proteases （acid protease，neutral protease，alkaline protease） were tested.The influence of substrate concentrations，enzyme contents，and hydrolysis time on the degree of hydrolysis，heme yield，and heme purity were examined.An orthogonal array experiment was used to determine the optimal heme extraction process.Finally，heme product was obtained by centrifugation and freeze-drying using the optimal enzymatic hydrolysis parameters，and the heme content of the product was measured using liquid chromatography-tandem mass spectrometry （LC-MS/MS）.The results showed that the heme yield and purity were 52.23% and 49.26%，respectively，when neutral protease was used for hydrolysis，substrate concentration was 4.0 g/100 mL，enzyme dosage was 2.0 g/100 mL，and enzyme hydrolysis time was 4 h.The retention time of heme product was consistent with the heme standard，and the content of heme was 50.24%.