Effects of Ultrasound-Assisted Alkaline Extraction on Antioxidant Activity and Functional Characteristics of Chicken Feather Keratin Peptides

In this research, we focus on enzymatic hydrolysis of chicken feathers, after chemical or chemical and ultrasound pretreatment. Our result illustrated that ultrasound pretreatment preserved the main structure and amino acid composition of extracted keratin as confirmed by the Fourier-transform infrared (FTIR) spectroscopy and gel-electrophoresis analysis. In addition, investigation showed that ultrasound-assisted chemical treatment was more effective on enzymatic hydrolysis and bioactivity as compared to only the chemical treatment. Thermo gravimetric analysis (TGA) characterization of hydrolyzed products, using Alcalase enzyme at different times, showed that decomposition temperature was decreased during enzymatic hydrolysis and the best antioxidant activity was achieved after 30 min of hydrolysis with the value of 90.43 +/- 4.03 % (5 mg/ml concentration). Also, it was found that hydrolyzed product indicated no cytotoxicity to SK-N-MC cells when the concentration is less than 0.312 mg/ml. In this paper, the results demonstrated that the ultrasonic-assisted enzymolysis processing seems to be effective for producing keratin antioxidant hydrolysate.