Regional nutritional profile and antioxidant activity of Gelidium sesquipedale from the Moroccan Atlantic coast

Gelidium sesquipedale is a red seaweed exploited in Morocco for its agar-agar quality. Samples were examined across the Moroccan Atlantic coast to evaluate their nutritional composition and antioxidant activity. The objective was to find out the regional impact on the biochemical properties of this seaweed. The obtained results have shown that the region factor does not affect the carbohydrate content. However, protein content was higher in the western sites (15.77% in Lahdida and 16.79% in Sidi-Rahal) compared to those from the southern sites (14.08% in Sidi El Ghazi and 14.76% in Amgriou). Regarding the phenolic contents, the results are similar in the west (5.69 and 5.38 mg gallic acid equivalent (GAE)/g respectively in Sidi-Rahal and Lahdida) but differ in the south (6.22 mg GAE /g in Amgriou and 4.78 mg GAE /g in Sidi El Ghazi) due to stranding phenomena in Amgriou. Moreover, this seaweed exhibits the highest radical scavenging capacity (DPPH) and Ferric Reducing Antioxidant Power (FRAP) values in the south (90.41 and 114.33 µg/mL in Amgriou; 103.76 and 110.5 µg/mL in Sidi El Ghazi). Hence, the exploitation of Gelidium sesquipedale harvested on the western and southern coasts of Morocco should extend beyond the sole production of agar-agar.