The utilization of poultry by-products improves food production and reduces environmental issues, increasing efficiency in the meat industry and food production. These by-products are treated like low-quality products and are often underutilized despite their potential for use in pharmaceuticals or cosmetics. These by-products from poultry meat production are rich in collagen and can be processed into various food and non-food products using enzymatic protein hydrolysis (EPH). EPH is one of the processing strategies that allows tailoring the products\’ physiochemical properties.
This thesis investigates the mode of action of some proteases that affect muscle collagen proteins in mechanically deboned chicken residue (MDCR). Analytical approaches are developed to optimize the EPH process, including testing different conditions, like protease choice, temperature, hydrolysis time, and enzyme loading on MDCR. This project conducted two screenings and an optimization step. Screening I aimed to scan a range of enzymes that were used to separate the muscle protein from collagen proteins. The selection of Exocut-TRL and Endocut-07L was based on their distinct features. A collagen-enriched substrate was produced to generate Screening II, which aimed to extract as many collagen peptides from the substrates as possible. As a result, Bromelain and Corolase-2TS were chosen due to their effectiveness in maximizing collagen protein extraction at 50 °C for 45 minutes while having a 0.5 % (w/w) enzyme loading. The optimization step was performed on conditions based on screening II. It investigated different parameters: temperature, hydrolysis duration, and enzyme loading on the samples hydrolyzed by the two selected proteases to create optimal conditions for utilizing these by-products.
Temperature was identified as a crucial parameter for maximizing the extraction of collagen peptides based on the last step of the process, the optimization step. Response Surface Modelling (RSM) was also conducted with the data obtained in the optimization step. RSM provided optimal conditions for extracting most collagen peptides and maximizing the yield for samples treated by Bromelain and Corolase-2TS were found at 60 °C for 45 minutes and 56 °C for 19 minutes, respectively, with an enzyme concentration of 1.38 % and 1.29 %, respectively. However, these models are not validated, meaning they are specific to the conditions applied in this thesis.