Rheology of Ulvan Derived from Ulva spp Pretreated by Microwave Hydrodiffusion and Gravity (MHG) as Innovative Drying Technology

Ulvan, a sulfated cell wall polysaccharide usually derived from Ulva spp, has garnered a growing interest due to its valuable biological features used in food, pharmaceutical, and cosmaceutical industries [1]. Research into fast and controlled drying is required because of the rising demand for seaweed biomass and its derivatives [2]. This study aims to study the impact of Microwave Hydrodiffusion and Gravity (MHG) on structural and rheological behaviors, and film development of ulvan. Fresh algal material was exposed to MHG at different irradiation powers. Microwave treatment was operated for 5 min at 160 \({\circ}\) C, 850 W, and 800 rpm to extract ulvan. The viscoelastic characteristics of ulvan were measured on an MCR302 controlled stress rheometer. The highest ulvan yield recovered under MHG conditions was employed to develop biodegradable films. The rheology of the formulated film was also examined. Results showed that the innovative MHG processing is a relevant drying method for seaweed preservation and ulvan recovery, with high molecular weight and rheological properties equivalent to their commercial counterparts.