Abstract: A non-thermal plasma/photocatalysis reactor, designed and fabricated in our laboratory, was used to decolorize water-soluble polysaccharides extracted from litchi flesh. Decolorization parameters such as the filling rate of alumina as a support for photocatalyst, voltage, polysaccharide concentration and treatment time were tested for their influence on decolorization efficiency. Meanwhile, a regression model was set up to describe decolorization efficiency as a function of the decolorization parameters by means of quadratic orthogonal rotary combination design. The results showed that when the filling rate of alumina, voltage, polysaccharide concentration and treatment time were 18.1%, 21.6 kV, 50.0 mg/mL and 33.8 min, respectively, the best decolorization results were achieved, with a decolorization efficiency of 91.2% and a polysaccharide retention rate of 87.4%.

Key words: litchi, polysaccharides, non-thermal plasma, photocatalysis, quadratic orthogonal rotary combination design