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Studies on Antioxidant Activity and Modified Methods of Polysaccharides from Pine Cone of Pinus Kora

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Tutor: YangZuo
School: Harbin Institute of Technology
Course: Biochemical Engineering
Keywords: pine cones of Pinus Koraiensis,polysaccharides,carboxymethylation,sulfated modif
CLC: R284
Type: Master's thesis
Year:  2012
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Abstract:
In recent years, more and more scholars are concerned about the biological activityof polysaccharides, study and develop a series of functional polysaccharides. However,there are few reports about the polysaccharides from pine cones of Pinus Koraiensis.Pinus Koraiensis are mainly distributed on the northeast of China, which provides thesufficient resources of material for research. In order to fill the blank of the study on thepolysaccharides from pine cones of Pinus Koraiensis, in this paper, the biologicalactivity and modified methods of polysaccharides from pine cones of Pinus Koraiensiswere studied.In this paper, the polysaccharides extracted from pine cones of Pinus Koraiensiswith hot water were precipitated by alcohol and studied the methods ofcarboxymethylation and sulfation. To improve the biological activities of thepolysaccharides from pine cones of Pinus Koraiensis, the process conditions of themethods of carboxymethylation modification and the method of sulfated modified wereoptimized and the results were also discussed.Comparing different methods of carboxymethylation, it is found that thepolysaccharides got8%while one plus soda modified, and got27.54%whilecontinuous of plus soda modified. Therefore, one plus soda carboxymethylation wasused in the modification of the polysaccharides from pine cones of Pinus Koraiensis inthis study. In the single-factor experiments of one plus soda, the optimal condition wastime4h, temperature40℃and chloroactic acid dosage0.6g. On the basis ofsingle-factor experiments, orthogonal experimental was designed to determine theoptimal parameters, and the optimum conditions were obtained as follows: temperaturewas50℃and chloroacetic acid dosage was0.8g. Meanwhile, the carboxymethylatedpolysaccharides with different degree of substitution under different process parameterswere investigated and compared the oxidation resistance. The result showed that whendegree of substitution of the modified polysaccharides was0.44-0.45, the antioxidantactivity reached30%.To study the method of sulfation, it showed that the yield of polysaccharide was50%while using concentrated sulfuric acid method and was40%while usingchlorosulfonic acid–pyridine method. Therefore, the concentrated sulfuric acid methodwas used for sulfation of polysaccharides from pine cones of Pinus Koraiensis. Withsingle-factor experiments, the optimal factors were as follows: time was0.5h, thevolume of concentrated sulfuric acid was10mL, and ammonium sulfate0.175g. Basedon the single-factor experiments, the orthogonal experiment was designed to determine the optimal parameters, time was0.5h, the volume of concentrated sulfuric acid was12mL, and ammonium sulfate dosage was0.175g. Meanwhile, the sulfatedpolysaccharides with different degree of substitution under different process parameterswere investigated and compared the oxidation resistance. The result showed that theantioxidant activity and the degree of substitution were significantly related, and theantioxidant activity reached60%.Finally, the antioxidant activities of polysaccharides of carboxymethylation andsulfation were studied and compared with polysaccharides without modification. Theresults showed that best antioxidant activity was obtained by sulfated polysaccharides,followed by carboxymethylated polysaccharides. In conclusion, the modifiedpolysaccharides both showed the ability to improve the antioxidant activity ofpolysaccharides from pine cones of Pinus Koraiensis.
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