Constructing ethanol-derived bioactive extracts using the brown seaweed Zonaria tournefortii (J.V.Lamouroux) Montagne performed with Timatic extractor by means of response surface methodology (RSM)

Abstract

Understanding the biochemical and antioxidant composition and capacity of a target biomass is the first step to its selectivity as functional food which can enhance the ability to promote health by reducing the risk of chronic diseases. The main purpose of this work was to employ response surface methodology (RSM) to determine the effect of the independent variables, % of ethanol (50–96%), time of sonication (0–20 min), and number of extraction cycles (6–18 cycles) in the primary extract of brown seaweed Zonaria tournefortii, studying the yield variation of some bioactive compounds, assessing the potential of these bioextracts to integrate as a natural additives or supplements in the functional food industry. The extractions were performed employing “Green Chemistry” techniques executed with the Timatic extractor, which applied pressurized ethanol solution at a maximum pressure of 8.5 bar through milled dehydrated biomass in the extraction vessel. Several parameters were assessed in the primary bioactive extract which included extract yield (11.56–28.49 g (100 g)⁻¹ dw), total chlorophyll content (0.14–1.42 g (100 g)⁻¹ dw), total carotenoid content (0.35–0.80 g (100 g)⁻¹ dw), total fucoxanthin content (0.04–0.13 g (100 g)⁻¹ dw), total phenolic content (3.58–5.84 g (100 g)⁻¹ dw), total flavonoid content (0.22–4.70 g (100 g)⁻¹ dw), DPPH (56.05–76.45%), and reducing activity (3.83–6.04 g (100 g)⁻¹ dw). A second objective was to determine the suitability of the residue for subsequent extraction of valuable compounds such as fucoidan (4.87 to 6.59 g (100 g)⁻¹ dw) and cellulose (18.88 to 20.27 g (100 g)⁻¹ dw), implementing the first step to a biorefinery strategy, using a cascade approach.