The Extraction, Isolation, Antioxidant Activities And Moisturization Of Polysaccharides From Ulva Fasciata

Ulva fasciata is one kind of precious medicinal and edible chlorophytan seaweeds, and extremely rich in nutritional and medicinal value. In this paper, the extraction process, isolation method, the physical and chemical characters of U. fasciata polysaccharides (UFP) were systematically studied, its antioxidant activity in vitro and moisture retention of tobacco were also been preliminarily explored.The main nutrition constituent of U. U. fasciata and mineral elements were determined. Analysis shows that U. U. fasciata not only contains a large number of nutrients that human body needed, but also contains rich mineral elements, among them, potassium, magnesium, iron is most abundant. Ulva fasciata is a kind of food which has the characteristics of high protein and low fat.Based on the single factor test, response surface method (RSM) was employed to obtain the best result of polysaccharide extraction rate. The results showed that the optimal conditions for the extraction of U.U. fasciata olysaccharide with ultrasonic-assisted were as follows:extraction time of 33 min, ultrasonic power of 620W, pulse recurrent time of 0s, polysaccharide extraction rate up to 14.14%. The physico-chemical properties of the crude polysaccharide were analyzed. Results showed that uva fasciata polysaccharide is a kind of acidic polysaccharides containing sulfate and uronic acid.The crude polysaccharides were isolated into four different components by ultrafiltration, named>100kD UFP、30-100kD UFP、 10-30kD UFP and<10kD UFP respectively. Their antioxidant activities were investigated on the basis of superoxide radical assay, hydroxyl radical assay, ABTS radical assay, and reducing power assay. The results showed that four polysaccharides all exhibited antioxidant properties, 10-30kD UFP has higher scavenging rate than other three components in superoxide radical, hydroxyl radical and ABTS radical.30-100kD UFP has the highest reducing power,10-30kD UFP comes second.UFP was purified using DEAE Sapharose Fast Flow and Sephadex-G100 column chromatographic column repeatedly. One water-soluble homogeneous polysaccharide UFP1-1 was obtained. High performance liquid chromatography producing a single symmetrical peak, indicated that it was homogeneous and molecular weight was 236kD.IR spectra showed that the sugar characteristic peaks were existed. Gas chromatography-mass spectrometry show that UFP1-1 mainly consists of rhamnose xylose and glucose and the molar ratio of 1:0.46:0.27.Four different components polysaccharides are sprayed over the tobacco. The results showed that U. fasciata polysaccharides offered good cigarette sensory quality and were suitable to cigarette. By taking the distilled water as reference, the variation of the moisture content in the different time points are mensurated by difference method to evaluate their moisturizing performance. The results showed that UFP can prevent moisture diminishing, excessive absorption of water, and it is a new bilateral humectant of cigarette.