Study On Extraction, Structure Characteristics, Antibacterial And Antioxidant Activities Of Polysaccharides From Canarium Album(Lour.) Raeusch

Canarium album(Lour.) Raeusch, also known as green fruit, blessinf fruit, is the fruit of the olive tree. It is not only one of the famous fruits in the tropics and sub-tropical, but also the distinctive agricultural product in Fujian Province. Besides of its edible value, Canarium album (Lour.) Raeusch has high nutritional value and medical value, such as dispelling the effects of alcohol, protecting the liver, anti-virus, anti-oxidation and so on. As one of the main active substances in the album fruit, the polysaccharides from Canarium album(Lour.) Raeusch (CP) have not been studied widely. In the paper, the extraction process, purification, functional properties and molecular characteristics of CP were studied. The results were as follows:(1) The paper used hydrochloric acid extraction, cellulose enzyme extraction, ultrasonic-microwave assisted extraction method respectively to extract the polysaccharides from the album fruit. Based on the single factor experiment, the paper adopted orthogonal experiment to optimize the extraction process, meanwhile, finding the best extraction method through the analysis of the three extraction methods. The results showed that:the optimum conditions of CP extracted by the hydrochloric acid extraction method were obtained as following:the concentration of hydrochloric acid0.15mol/L, solid-liquid ratio1:50(g:mL), extraction time4h, under these conditions, the yield of polysaccharides was6.06%.The optimum conditions of CP extracted by the cellulose enzyme extraction method were obtained as following:the ratio of enzyme/substrate1.0%, solid-liquid ratio1:30(g:mL), reaction temperature45℃, under these conditions, the yield of polysaccharides was6.03%.The optimum conditions of CP extracted by the ultrasonic-microwave assisted extraction method were obtained as following:the ultrasonic-microwave time50min, extraction temperature70℃, solid-liquid ratio1:70(g:mL), under these conditions, the extraction ratio of polysaccharides was up to11.7%. The results showed that:the yield of CP extracted by the ultrasonic-microwave assisted extraction method was the highest, while the cellulose enzyme extraction was the lowest.(2) Based on the single factor experiment and orthogonal experiment, the optimum condition of deproteinization of CP were obtained as following:the reaction temperature40℃, hydrolysis time70min, the dosage of enzyme70U/mL, under these conditions, the rate of removed protein was78%.X-5of macroporous adsorption resin was used to decolor the polysaccharide, the optimum process parameters were50mL5mg· mL-1polysaccharides solution, adding15g X-5, oscillating for5h at25℃, the decolourization rate was43%, the retention rate of polysaccharides was98%.The paper adopted the reverse flow dialysis for24h to remove residual small molecules in order to increase the purity of CP.(3) With the crude polysaccharides (CCP) and the pure polysaccharides (PCP) as experiment objects, the antimicrobial activity of CP was studied. The results showed that PCP almost had no antibacterial activity against all tested bacteria, while the antibacterial activities against Salmonella, Bacillus subtilis of CCP were more obvious, but it almost had no antibacterial activity against other experimental bacterial species. The minimum inhibitory concentrations against Salmonella, Bacillussubtilis were25mg/mL,12.5mg/mL, respectively.(4) The antioxidant activities of CCP and PCP in vitro were studied, which were compared with those of Vc. The results were summarized as follows:Both CCP and PCP had obvious scavenging ability against the hydroxyl radical (·OH)and superoxide anion radical (O2-·), but the scavenging ability against1,1-diphenyl-2-picrylhydrazyl radical(DPPH·) was weaker. By comparison, the antioxidant activities of CCP in vitro was better than PCP. However, CCP, PCP and Vc almost had the same total antioxidant capacity. (5) After the deproteinization, decoloring, dialyzing, PCP was separated by DEAE Sepharose CL-6B agarose gel column chromatography, three different separation components were obtained, named as CP1, CP2, CP3. The SEC-MALLS-RI combination instrument was chosed to analyze the molecular characteristics. The result showed that, all the three components were medium dispersed and tight uniform large spherical molecules. The weight-average molecular weight of the three different components are6.693×105,3.937×105,4.912×105g·mol-1respectively. According the analysis results by Fourier transform infrared spectroscopy, CP1, CP2and CP3were the acidic polysaccharides with-COOH.