Optimisation of a Green Ultrasound-Assisted Extraction (UAE) Methodology for Obtaining Maximum Antioxidant Activity from Red Algae and Determination of the Co-Extracted Compounds

Antioxidants are of great interest in multiple applications, so there is a growing trend in the search for antioxidant compounds of natural origin, such as the red algae Palmaria palmata and Porphyra sp. A green ultrasound-assisted extraction method has been optimised to obtain the highest antioxidant activity, and subsequent characterisation of the antioxidant compounds present in the extracts. The antioxidant activity was determined by DPPH-RSA, FRAP and ORAC assays. The highest antioxidant activity was obtained for Porphyra sp. (DPPH: 87.64