Potential of innovative pre-treatment technologies for the revalorisation of residual materials from the chicken industry through enzymatic hydrolysis

The effect of microwave, ultrasound and high-pressure pre-treatment prior to enzymatic hydrolysis of mechanically deboned chicken residuals was evaluated. Increased protein extraction yield was observed for high-pressure pre-treatment at ≥400 MPa. Enhanced antioxidant activity was found in hydrolysates pre-treated with high-pressure (200 MPa) and ultrasound (900 W). Hydrolysates with higher protein solubility over pH were found after pre-treatments at 200 and 600 MPa, and 1 and 10 min microwave at 40 °C, with the most efficient option being the shortest microwave treatment. Furthermore, pre-treatments with ultrasound at 600 W, microwave for 1 min at 40 °C, and high-pressure at 200 MPa seem to have the potential to induce formation of peptides with higher lipid associating properties. The increase in meat consumption resulting from the rise in human population, has led to increased demand for relevant nutritional (protein) sources together with the need for proper utilisation of residual materials and reduction of food waste footprint. Thus, assessment and validation of novel technologies that allow unexploited materials, earlier regarded as waste, to be transformed into high-value products is of great interest for the industry within the current global framework. Enhanced extraction yield and bio- and techno-functionality will lead to high-value markets, while minimising environmental footprint. This article focuses on the potential of microwave, ultrasound and high-pressure technologies as pre-treatment strategies prior to enzymatic hydrolysis of mechanically deboned chicken residuals towards production of high-value peptides. The results show that the applied technologies are able to enhance the properties of the resulting peptides in terms of overall protein extraction and bio- and techno-functional properties (such as protein solubility over pH, antioxidant activity). Microwave pre-treatment is shown as a rapid method for increased protein solubility over pH; ultrasound pre-treatment increases the antioxidant activity of the peptides in a power-dependent manner; high-pressure pre-treatment has the potential to increase protein solubility, antioxidant properties and protein extraction, depending on the applied pressure. To achieve certain bio- or techno-functional peptide properties, choosing specific technologies and operational conditions is needed. Thus, relevant industry sectors will benefit from these results in light of their strategy towards valorisation of residual materials similar to mechanically deboned chicken, through enzymatic hydrolysis.