Weak shock wave-mediated fucoxanthin extraction from Sargassum spp. and its electrochemical quantification

Abstract

Fucoxanthin, a carotenoid found in Sargassum spp., possesses essential applications in the food and pharmaceutical industries. However, conventional methods for extracting fucoxanthin suffer from substantial limitations. This study demonstrates that shock wave-induced cavitation can be an efficient and selective extraction method. Suspensions of 100 mg of dried powdered algae with 4 mL of solvent (80 % ethanol) were exposed to four extraction methods at 25 and 50 °C. Four thousand single-pulse shock waves (SP-SWs) and two thousand dual-pulse shock waves, i.e., tandem shock waves (T-SWs), with a positive peak pressure of approximately 70 MPa, were compared with exposure for 30 min to a 40 kHz, 160 W-ultrasound bath (USE-B) and 5 min sonotrode extraction (USE-S) at maximum energy. A differential pulse voltammetry method for quantifying fucoxanthin was used for the first time, demonstrating that it is as fast and precise as other highly sensitive techniques. Independent of the extraction method, higher fucoxanthin content was obtained at 50 °C. At both temperatures, the total phenolic and flavonoid content values recorded after USE-S and T-SWs (delay ~220 μs) extraction were significantly smaller than those achieved for USE-B and SP-SWs. At 50 °C, the fucoxanthin content obtained was lower for the USE-S and T-SWs, opening the possibility of selective extraction. Moreover, this is the first time that the fucoxanthin content of Sargassum spp. from the Mexican Caribbean coast has been reported.