Effect of different drying methods on the physicochemical properties and antioxidant activities of mulberry leaves polysaccharides

This study aimed to optimize the suitable drying method to obtain high yield of polysaccharides from mulberry leaves and to determine their structural characterization and antioxidant activities. The effects of three different drying methods such as air dried, hot air dried (55 °C, 65 °C & 75 °C) and freeze dried on the physicochemical and antioxidant properties of mulberry leaves polysaccharides were studied using gas chromatography, high performance gel permeation chromatography, Fourier transform infrared spectroscopy, scanning electron micrography and antioxidant assays. Results revealed that pre-treatment remarkably influenced the changes in their physicochemical and antioxidant properties. In comparison with the other drying techniques, freeze dried polysaccharides showed more rough morphologies and significant antioxidant property. The yield of polysaccharides from the freeze dried sample was about 28.88% higher than the yield of hot air dried sample. The MDA activity of freeze dried sample was about 95.45%. Overall, the results suggested that the freeze drying technique was the appropriate method to extract polysaccharides from mulberry leaves that offered significant biological properties.