Decoloration And Antioxidant For Polysaccharides From Plants By Non-thermal Plasma-Photocatalysis Technology

The non-thermal plasma reactors were designed, manufactured, and appliedto the decoloration of the polysaccharides from Longan, according to the principlethat dielectric barrier discharge (DBD) can generate non-thermal plasma (NTP).The non-thermal plasma-photocatalysis reactors were used to decolor thepolysaccharides from Litch when the activated alumina particles loaded the TiO2were added into the NTP devices, because the free radical can be produced byphotocatalysis in the stimulation of the ultraviolet which was generated throughDBD. The antioxidant activities of the polysaccharides from Longan and Litchiwere investigated with Vc as the referent. The antioxidant activities of thepolysaccharides, which were treated with or without the non-thermalplasma-photocatalysis technology, were compared.Polysaccharides from Longan with the intitial concentration40.0mg/mL asthe research object, the effects of the air relative humidity on non-thermal plasmawas discussed. The results showed that the decolorization rate of Longanpolysaccharides gradually decreased and the retention rate increased with theincrease of air relative humidity. There were the negative correlation betweennon-thermal plasma and air relative humidity. The suitable air relative humiditywas50.0%after balancing the decolorization rate and the retention rate.Decolorization of polysaccharides from Longan with the initial concentration40.0mg/mL was studied by using non-thermal plasma reactor. The regressionequation is as follows.Y=55.04+1.61Z21+0.73Z20.091Z30.039Z1The optimum decolorizing conditions were determined by the method of quadraticorthogonal rotation combination design, based on the single factor experiments.The results showed that the rate of decolorization and the retention rate ofpolysaccharides reached80.5%and87.6%, respectively, under the conditions thatthe flowrate of polysaccharides solutions was30.0mL/min, the voltage ofelectrodes21.0kv, and the processing time20.6min.Decolorization technology of polysaccharides from Litchi was studied by using non-thermal plasma-photocatalysis reactor. The regression equation is asfollows.Y=25.86+0.36Z+2.03Z+0.62Z+1.35X0.02Z20.05Z30.006Z20.02Z212341234The experimental results showed that the rate of the decolorization and theretention rate of polysaccharides reached91.2%and87.4%, respectively, underthe optimum decolorizing conditions that the filling rate of alnmina supportedphotocatalysis was18.1%, the voltage of electrodes21.6kv, the polysaccharidesconcentration50.0mg/mL, and the processing time33.8min.The experimental results for antioxidation showed that the polysaccharidesfrom Longan and Litchi had some antioxidant activity. Comparing with the Vc, theability of scavenging hydyoxyl radical was equivalent to15.5%and9.1%of Vc,respectively. Reducing power was equivalent to9.1%and8.5%of Vc,respectively. The ability of scavenging superoxide anion radical was weak,equivalent to0.5%and0.4%of Vc, respectively. The antioxidant activities of thepolysaccharides treated by the non-thermal plasma-photocatalysis technologydecreased by20%to40%.The non-thermal plasma-photocatalysis technology had the followingadvantages: simple operation, no secondary pollution, efficient decolorization andso on. Therefore it would have broad application prospects in the field ofdecolorization of polysaccharides from plants.