Chicken feathers are an abundant residue and a suitable material for obtaining soluble keratin. This study explored the combination of physical, chemical and enzimatic processes to maximize protein yield. Initially, chicken feathers were washed, ground, and subjected to electron beam irradiation at doses from 0 (control) to 25 kGy. Keratin was then solubilized using 0.5 M Na₂S at 18°C, followed by H₂O₂ purification. A thermal-alkaline treatment (0.5 M NaOH, 1:50 w/w, 95°C for 2 min) was evaluated as an alternative for solubilization. Finally, hydrolysis using alcalase, trypsin, or bromelain was conducted on the residual solid. Results showed a soluble keratin yield of 92.78% with Na2S and 25 kGy, significantly surpassing the control (75.55%). While NaOH extraction achieved a slightly lower yield (90.71%), alcalase treatment of the solid residue yielded an additional 11.88%, achieving an overall 91.81%. Further studies should assess the use of the hydrolysates as animal feed.
Sinche-Serra et al. (Mon,) studied this question.