Physicochemical and functional properties of polysaccharides from fresh litchi fruit pulp by magnetically induced...

This study investigates the effects of different excitation voltages (200-800 V) on the physicochemical and functional properties of litchi polysaccharides (LPs) extracted from fresh litchi pulp by magnetic induction electric field (MIEF)-assisted three-phase partitioning methods. The study showed that the combined thermal and non-thermal effects induced by moderate MIEF voltages (400-600 V) led to structural modifications in LPs, resulting in increased total sugar content from 69.01 % to 75.64 %, higher galacturonic acid from 32.13 % to 34.36 %, higher molecular weight (91.08-98.93 × 10⁵ g·mol^-1), reduced protein content (0.43 %-1.58 %), and a looser, more porous surface morphology compared to LP-0. These physicochemical changes contributed to improved thermal stability, rheological property, antioxidant activity (with ABTS^·+ radical scavenging IC50 values of 0.19-0.40 mg/mL), and glucose adsorption capacity (reaching 1.56-1.73 mmol/g under 100 mM glucose). However, excessive excitation voltage at 800 V caused structural damage due to intense thermal effects, resulting in reduced molecular weight and decreased rheological and emulsifying properties. Therefore, the results suggest that moderate MIEF voltages (400-600 V) can effectively enhance the functional properties of LPs, providing a promising and practical technology for the extraction of plant-derived polysaccharides.