The Role of Ultrasound Cavitation Combined with Alcalase Enzyme in Improving the Structural and Antioxidant Attributes of Sulfated Polysaccharide from Yellowfin (Thunnus albacares) Skin

Alcalase enzyme (1 mg) and ultrasound (400 W) at 0-20 min were applied to obtain sulfated polysaccharides from yellowfin skin. Applying 15 min ultrasound resulted in a 0.12% increase in the rate of recovery yield. The intact structure of polysaccharides was determined by Fourier transform infrared spectroscopy, X-ray diffractometry, and scanning electron microscope. Ultrasound improved the thermal behavior of sulfated polysaccharides by affecting their microstructure, as analyzed by DSC. The color characterization (L*, a*, and b*) of ultrasound-treated samples was found to be superior compared to the control. Applying 15 min led to 16% and 9% enhancing DPPH and ABTS radical scavenging activities along with improving ferric-reducing antioxidant power of the polysaccharide.