Innovative technologies assisted biorefinery processing on Irish brown seaweed and its products valorisation

Abstract: The global market of seaweeds was USD 10.31 billion in 2020 and estimated to reach around USD 22.13 billion by 2024. Drying is a common seaweed post-harvest processing technique and is the most common process after blanching to further stabilize the biomass of fresh, harvested seaweed. In this study, both hydrodynamic and acoustic cavitation technologies were introduced into seaweed post-harvest process. There were 76 volatile compounds detected in blanched and dehydrated Alaria esculenta. Freeze-dried samples after treatment with microwave alone (at 1000 W) and microwave (800 W) combined with ultrasound (at 50% amplitude) had the highest retention rate of volatile compounds (up to 98.61%). Regarding mineral content, drying methods significantly affected (P < 0.05) the content of Ca, Co, Cu and Fe, while blanching treatments significantly affected (P < 0.05) the content of Na, Cu, Fe and Mn. Model Page was the best fitting ultrasound assisted drying kinetics. Ultrasound assisted fluidized bed drying was proved significantly reducing drying time as well as retaining total phenolic compounds in Ascophyllum nodosum. Blanching before drying showed lower energy consumption and drying time considerably. A sequential seaweed biorefinery process incorporated with both hydrodynamic and acoustic cavitation was then developed to produce muti products from Irish brown seaweed including laminarin, alginate and plant-based protein. All the target compounds showed identical qualities as the commercial ones but using a relatively low-cost and efficient processing.