Dual-Enzymatic Production and Techno-Functional Characterization of Chicken Feet Collagen Hydrolysate Processed in a Cheese Whey Medium

This study investigated the valorization of chicken feet, an underutilized poultry by-product, through enzymatic hydrolysis to obtain a protein hydrolysate with improved functional properties. Enzymatic treatment was carried out using Enzy-Mix U100 and collagenase from Streptomyces lavendulae, with cheese whey applied as a process medium. The resulting protein hydrolysate contained 59.1% protein and was characterized by high levels of glycine (31.64 g/100 g protein), hydroxyproline (10.91 g/100 g protein), and alanine (10.58 g/100 g protein). The hydrolysate exhibited strong techno-functional performance, with a water-binding capacity of 580%, an emulsifying activity index of 166 m2/g, and an emulsion stability index of 31 min. Microstructural analysis revealed irregular porous particles typical of freeze-dried protein hydrolysates, reflecting structural modification of collagen during enzymatic treatment. Mineral analysis showed notable levels of sodium (463.1 mg/100 g) and magnesium (351.8 mg/100 g). Microbiological evaluation demonstrated high sanitary quality, with a total viable count of 100 CFU/g and absence of coliforms, Escherichia coli, yeasts, and molds in 1 g of product. The technological process reduced the characteristic odor of chicken feet while maintaining a light color and good dispersibility. These findings confirm the potential of enzymatic hydrolysis as a sustainable strategy for converting poultry by-products into safe, value-added functional protein ingredients for food applications.