Effect of heating treatment on the properties of enzymatic hydrolysis of chicken protein

In order to analyze the effect of heating treatment on the hydrolytic properties of chicken protein, the thermal behavior of chicken protein was investigated by differential scanning calorimetry(DSC), and the effect of heating temperature on the content of sulfhydryl(SH) groups, disulfide(S-S) bonds in chicken protein and the release of amino acids and peptides during the enzymatic hydrolysis of chicken protein by Alcalase and Papain was determined. Results show that chicken protein exhibits a thermal curve with four endothermic transitions at 63.7℃, 67.6℃, 74.3℃ and 77.9℃. Increasing of heating temperature result in a concomitant decrease in the content of SH groups and a steady increase in the content of S-S bonds, while the content of SH groups plus reduced S-S bonds remained unchang below 80℃, and decrease above 80℃. Heating treatment before hydrolysis decrease the release of amino acids and low-molecular-weight peptides, and the recovery of soluble nitrogen, but increase the release of large-molecular-weight peptides during the enzymatic hydrolysis of chicken protein. It is suggested that heat treatment parameters could be chose according to the application aim of hydrolysate.