Abstract:Using crude polysaccharides from pineapple pomace as the raw material，the deproteinization and decoloration process conditions were studied and the antioxidant activity of the purified polysaccharides were also investigated.Seven methods were used to select the optimal deproteinization method with the rate of deproteinization and polysaccharide retention as indexes，including salting out method，trichloroacetic acid（TCA）method，Sevag method，TCA-n-butanol method，TCA-Sevag method，polyamide method and enzymatic method.Then，activated carbon was used to decolorize of polysaccharide solutions after removal of protein，and the conditions was optimized by orthogonal test on the base of single factor experiments.Results indicated that the method of TCA-n-butanol had the ideal deproteinization effect，the deproteinization rate and polysaccharide retention rate were reached to 81.47%and 85.91%，respectively.The optimum decoloration conditions were added 3.0%active carbon at sample pH value of 4.0，with temperature at 60 °C for 80 min，the decolorization rate and polysaccharide retention rate were 64.60%and 83.97%，respectively.The purified polysaccharides possessed scavenging capacity against DPPH·and ABTS+radicals with a dose-dependent relationship.The concentration of 3.0 mg/mL scavenged 83.27%DPPH·and 49.12%ABTS+radicals，respectively.The results demonstrated that these methods can efficiently remove protein and pigment from pineapple pomace polysaccharides，and the purified polysaccharides had stronger antioxidant activities.