Extraction and deproteinization of cucumber polysaccharide with high scavenging ability toward superoxide anion

Preparation and antioxidant activity of polysaccharide from cucumber (Cucumis saticus L.) were investigated. The crude polysaccharide was prepared by the method of hot-water extraction. The percentages of deproteinization and polysaccharide loss were compared as indexes using the trichloroacetic acid (TCA) method and CaCl2 method, respectively. The infrared (IR) spectra analysis and content analysis showed that the TCA method exhibited higher percentage of deproteinization and a little higher percentage of polysaccharide loss than the CaCl2 method. The scavenging ability of cucumber polysaccharide toward superoxide anions was evaluated by means of chemiluminescence (CL). The results show that the cucumber polysaccharide had high scavenging ability toward superoxide anion. Key words: Cucumber polysaccharide, extraction, deproteinization, analysis, antioxidant activity.