Enhancing the Extraction of Polysaccharides and Antioxidants from Macroalgae Using Sequential Hydrothermal-Assisted Extraction Followed by Ultrasound and Thermal Technologies

Abstract

Fucose sulphated polysaccharides (FSPs) and glucans have recently attracted the attention of the scientific community due to their wide range of biological activities. Both polysaccharides should ideally be selectively extracted using innovative technologies with high extraction efficiency. This study aims to: (1) Optimise the extraction variables used in hydrothermal-assisted extraction (HAE) to obtain high yields of FSPs, total glucans, and antioxidants from Laminaria hyperborea; (2) to apply these optimised protocols to other brown macroalgae; and (3) to explore the application of ultrasound and thermal technologies to increase the recovery of polysaccharides from the residual biomass. Box-Behnken design (three-factor, four-levels) was employed to optimise the HAE variables, and principal component analysis was used to evaluate the recovery of polysaccharides from the residual biomass. The optimal HAE conditions were 120 °C, 80.9 min, and 12.02 mL/g macroalgae from L. hyperborea. The best sequential application of ultrasound and thermal treatment achieved an additional 2971.7 ± 61.9 mg fucose/100 g dried macroalgal residue (dmr) from Ascophyllum nodosum and 908.0 ± 51.4 mg total glucans/100 g dmr from L. hyperborea macroalgal residues.

Exploring Ultrasound, Microwave and Ultrasound–Microwave Assisted Extraction Technologies to Increase the Extraction of Bioactive Compounds and Antioxidants from Brown Macroalgae

“…Polysaccharides, such as carrageenan, agar and alginates, have been traditionally used as gelling, thickening and stabilising agents in food, cosmetic and pharmaceutical formulations [9]. Moreover, recent studies have focused on the biological activities of macroalgal polysaccharides, i.e.…”

“…Innovative technologies, such as ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE), have been recently explored to extract multiple bioactive compounds from macroalgae, as reviewed by Garcia-Vaquero et al [4] and Tiwari [23]. Thereby, the use of UAE processes alone [24][25][26] or sequentially with other extraction technologies [9] has shown promising advantages when extracting polysaccharides such as FSPs, glucans and other antioxidant compounds from macroalgae. Moreover, the extraction of carbohydrates and other antioxidant compounds have also been explored using MAE from terrestrial plants [27,28] and macroalgae [14,29].…”

“…Moreover, the extraction of carbohydrates and other antioxidant compounds have also been explored using MAE from terrestrial plants [27,28] and macroalgae [14,29]. Understanding the impact of multiple process parameters on the efficiency of the extraction and on the yield of carbohydrates and other high-value compounds obtained from macroalgae is one of the key critical points that will influence the design and utilisation of macroalgal biomass following a biorefinery concept [9]. However, despite being some of the most promising novel technologies, to our knowledge, there are currently no studies researching the simultaneous application of ultrasounds and microwaves to generate high-value compounds from macroalgae.…”

Fucoidans: Downstream Processes and Recent Applications

“…Recently, combined sulfated polysaccharides extraction protocols were optimized from different brown algae species using hydrothermal-assisted extraction (HAE) followed by sequential ultrasound and thermal technologies [123]. Similarly, subcritical water extraction was applied to increase the production yield of fucoidans from Nizamuddinia zanardinii [124]; such mild conditions may be advantageous to preserve the native chemical backbone and physicochemical characters of fucoidans.…”

Effect of a Laminarin Rich Macroalgal Extract on the Caecal and Colonic Microbiota in the Post-Weaned Pig

“…The laminarin enriched extract was sourced from BioAtlantis Ltd (Clash Industrial Estate, Tralee, Co. Kerry, Ireland). The laminarin rich extract was obtained from Laminaria spp using hydrothermal assisted extraction by applying optimised extraction conditions as described in our previous publication [33]. The crude extract was partially purified in order to enhance polysaccharide content and to remove or reduce proteins, polyphenols, and the excess amount of mannitol and alginate, by mixing the crude extract with pure ethanol (to remove polyphenols) followed by water (to remove protein) and calcium chloride (to remove alginates).…”