Hemoglobin hydrolysates from porcine blood obtained through enzymatic hydrolysis assisted by high hydrostatic pressure processing

The purpose of this work was to obtain discoloured hemoglobin (Hb) hydrolysates from porcine red blood cells fraction by combining enzymatic hydrolysis and high hydrostatic pressure (HHP) treatments. Samples of Hb were submitted to treatments of enzymatic hydrolysis by trypsin (EC 3.4.21.4) or pepsin (EC 3.4.23.1), under controlled conditions of temperature and pH, for 2, 6 and 24 h, and pressurization at 400 MPa, at 20 °C for 15 min, after the addition of the proteases. To evaluate the effects of the proteolysis reactions, the effectiveness of discolouration, the extent of hydrolysis as the percentage of non-protein nitrogen, and the SDS-PAGE electrophoretic profiles of the hydrolysates were determined. The results showed that HHP had a significant influence on enzymatic hydrolysis of Hb by trypsin, whereas did not improve the extent of proteolysis in the case of pepsin. The main conclusion derived from this study is that pressurization of Hb samples after the addition of trypsin enhanced enzymatic hydrolysis of the Hb, hence permitting a decrease in the incubation time.Industrial relevanceThe present study is focussed on assessing the effects of enzymatic hydrolysis with trypsin or pepsin assisted by HHP treatment on the discolouration of Hb from porcine blood. HHP treatment was able to increase the activity of trypsin and to enhance discolouration effectiveness of Hb with pepsin. The results from this work corroborate the potential of the application of HHP processing combined with enzymatic treatments on the development of food ingredients from porcine blood.

Research highlights
► The combined application of enzymatic hydrolysis with trypsin and pepsin and HHP processing on obtaining discoloured hydrolysates from porcine hemoglobin is investigated.
► The application of HHP treatment enhanced enzymatic hydrolysis of hemoglobin with trypsin whereas did not affect the hydrolytic activity of pepsin.
► Pressurization enhanced Hb discolouration by pepsin, due to the combined effect of HHP and acidification.