Potential application of static hydrothermal processing to produce the protein hydrolysates from porcine skin by-products

Protein hydrolysates from animal by-products have good bioavailability and high nutritional value; thus, they could be used for value added foods, cosmetics and pharmaceutical products. This study investigated the potential of hydrothermal treatment for protein hydrolysis of porcine skin by-product at high temperature (150–250 °C) and pressure (350–3900 kPa). The control showed free amino acid content of 1.4 mg/ml and then increased to 9.4 mg/ml after hydrothermal treatment at 250 °C & 3900 kPa which was named porcine skin hydrolysate PSH-VI. In empirical model fitting, the linear combination coefficient of pressure and temperature (β₅) showed the positive values with statistical significance (P < 0.05). Those results suggest that both elevated temperature and pressure are required for protein hydrolysis as compared to single use of elevated temperature or pressure only. The synergistic effect of temperature and pressure on protein hydrolysis was confirmed in the hydrothermal treatment. On protein gel electrophoresis, no obvious peptide band of >15 kDa was observed after treatment above 190 °C & 1100 kPa treatment. This study showed the potential of hydrothermal processing to produce protein hydrolysates used for food ingredients, cosmetics or pharmaceutical products from animal by-products as a green and sustainable technology.