Enhanced extraction of Pleurotus ostreatus polysaccharides via plasma-ultrasound synergy: Kinetics modeling and functional characterization

The limitations of traditional extraction methods in terms of efficiency and environmental sustainability have highlighted the urgent need for advancements in extraction technology. Pleurotus ostreatus (oyster mushroom), a functional mushroom known for its antioxidant properties, was investigated for its potential in nutraceutical and food applications. This study evaluates the extraction efficiency, structural integrity, bioactivity, and energy efficiency of Pleurotus ostreatus polysaccharides obtained through eco-friendly, non-thermal techniques known to enhance mass transfer and disrupt cell wall structures. These include ultrasound-assisted extraction (UAE), plasma-assisted extraction (PAE), and plasma pretreatment-ultrasound extraction (PPUE), in comparison to conventional hot water extraction (HWE). PPUE, under optimal conditions (1 min plasma pretreatment and 30 min ultrasound), achieved the highest crude polysaccharide yield (12.0 %), surpassing PAE, UAE, and HWE by 23.7 %, 57.5 %, and 72.4 %, respectively. PPUE also exhibited superior energy efficiency (975.6 kJ/g), indicating lower energy consumption per unit of extracted polysaccharide. Additionally, it showed enhanced water solubility index (65.7 %) and water holding capacity (4.66 g/g), alongside the highest total phenolic content (67.07 μg GAE/g) and antioxidant activity (ABTS, 81.5 %), reflecting its ability to preserve functional compounds effectively. Structural analyses revealed that PPUE synergistically combines oxidative cleavage by plasma-generated reactive oxygen and nitrogen species with ultrasound cavitation, thereby enhancing cell wall disruption, permeability, mass transfer, and polysaccharide release. Kinetic modeling confirmed that PPUE follows a two-site extraction mechanism, effectively balancing rapid desorption and controlled diffusion. While this study demonstrates PPUE as a promising and energy-efficient extraction method, further investigation is recommended to validate its applicability across other bioresources and to scale-up for industrial applications.