Sequential Hydrolysis of Chicken Feathers Composed of Ultrasound and Enzymatic Steps: An Enhanced Protein Source with Bioactive Peptides

Chicken feather is a massive by-product. Its incorrect disposal can lead to serious environmental impacts. However, chicken feather is a promising low-cost keratin source. Keratin products have a wide application in the food and pharmaceutical industry. Mostly, chicken feathers are hydrolyzed by hydrothermal processes, and then applied into animal feed formulations. Despite the low cost, the hydrothermal hydrolysis leads to uncontrolled and low hydrolysis yield. Therefore, the aim of this work was to develop and optimize a sequential strategy of chicken feathers hydrolysis composed of ultrasound and enzymatic hydrolysis (savinase^®) steps. In the first research step an experimental design was built and the optimum hydrolysis condition was obtained at 50 °C and 12.5% (enzyme/chicken feather), using three integrated rectors containing enzyme/substrate and sodium disulfite. Then, the ultrasound probe was added in the experimental apparatus in order to investigate the enzymatic hydrolysis assisted by ultrasound treatment. The enzymatic hydrolysis assisted by ultrasound treatment led to high concentrations of peptides, including a dipeptide (245.1868 m/z). Thus, the sequential hydrolysis strategy composed by two green technologies proposed in this study, enhanced the degree of hydrolysis of chicken feathers, producing bioactive peptides that can be used as ingredients in food products and other sectors.