Influencing factors of feather protein denaturation and optimization of enzymatic hydrolysis conditions under ultra high pressure

In order to explore the influencing factors of feather protein denaturation and the best process of ultra-high pressure enzymatic hydrolysis, feather meal（chicken feather） was chosen as research material in this experiment.After denaturation in different solvents（urea and guanidine hydrochloride）, feather protein was hydrolyzed by high pressure enzyme.The process conditions（pressure, enzymatic hydrolysis temperature, enzymatic hydrolysis time and pH value） were optimized by the ultra-high pressure enzymatic hydrolysis method through the design of single factor test and L₉（3~4） orthogonal test, and the amino acid content in the feather enzymolysis solution was determined by using automatic amino acid analyzer. The results showed that the feather powder protein was treated with urea, and the highest protein solubility was 47.65% when the temperature was 90 ℃, the treatment time was 2.5 h and the concentration of urea was 18 g/L. The feather powder protein was treated with guanidine hydrochloride, and the highest protein solubility was 47.50% when the temperature was 90 ℃, the treatment time was 2.5 h and the concentration of guanidine hydrochloride was 4 g/L. The enzymatic hydrolysis time was 5 h, the enzymatic hydrolysis pressure was 180 MPa, the enzymatic hydrolysis temperature was 55 ℃, and the pH value was 8, these are the best ultra-high pressure enzymatic hydrolysis process. Under this process, the feather ultra-high pressure enzymatic hydrolysis rate was the highest, reaching 49.64%. There were 17 kinds of amino acids in feather hydrolysate, and total amino acid（TAA） was 66.08%, essential amino acid（EAA） was 23.23%, non-essential amino acid（NEAA） was 42.85%, of which glutamic acid and proline content were most. The results indicated that the ultra-high pressure enzymatic hydrolysis research method was reliable and the effect was good.