The effect of pulsed electric field-assisted treatment parameters on crude aqueous extraction of Laminaria digitata

Pulsed electric field (PEF) assisted extraction was used to produce crude aqueous extracts from the brown alga Laminaria digitata to explore different treatment conditions. The experiment was set up using a central composite design and fitted to a response surface model with three factors: biomass concentration (0.17–3.28% dry weight), number of pulses during PEF treatment (12–268 pulses) and the initial temperature of algae suspension (12–48 °C). The temperature change during treatment, the extraction yield, total polyphenol and total carbohydrate content were determined. During PEF treatment the temperature change ranged from − 1 to 13 °C. The yield of supernatant and extraction yield was 70 ± 15% and 15% ± 8%, respectively. The total polyphenol content was 4.0 ± 1.6 mg GAE (100 g)−1 DW and the total carbohydrate content was 2.6 ± 2.9 mg GE g−1 DW. The supernatant yield, polyphenol content and carbohydrate content were the highest for the lowest biomass concentration. The number of pulses during PEF treatment was positively correlated to the temperature change, whilst the initial temperature was negatively correlated to the temperature change. This study shows that PEF assisted extraction can be used for the extraction of valuable compounds from L. digitata without recourse to high heat or organic solvents.