Study On Extraction And Physical-chemical Properties Of Pectin From Sunflower Head

Pectin is the most important soluble dietary fiber in sunflower head, the production of pectin in China is still lagging, and the technology of extraction which costs lower and products higher is not perfects. In order to improve the yield and quality of pectin, and actualize the reuse of depectin pomace, we compared the effects of tradition acid and microwave-assisted method extraction on pectin yield and quality, adopts technical of active carbon and resin decolor the solution of pectin, Finally, gained the pectin with alcohol diposition. The physical-chemical properties of the sunflower head pectin were also investigated. The result shows:(1) The materias were ground by a mill to pass a 60-mesh size screen,destroying enzyme inboiling water about 3min and washed with water at 75℃and stirred slowly for 15 min at a solid: Liquid ratio of 1:20 ahead of pectin extraction, will gain a high pectin yield, the pectin has little impurity and has good colour and luster.(2) The tests were optimized through good single factor selecting and Response Surface Methodology (Central Composite Rotatable Design). The predicted values were obtained by equation very well.The conventional extraction optimal conditions is temperature 89℃, action time 100 min, pH 3.4 and rate of solid/liquid 1:25; and the MAE optimal conditions is microwave power 450 W, action time 6.5 min, pH 3.4 and rate of solid/liquid 1:20, were determined by response surface methodology (RSM). Application of MAE in the extraction from dried sunflower heads dramatically reduced extraction time compared with conventional extraction.(3) Through single factor analysis method contrast the decoloration effect of carbon and resin. It shows that the effect of decoloration with resin is better than active carbon, and the method of decoloration with resin is suitable for industrial production. We can get the conclusion by good single factor selecting experiment: pH is 4, temperature at normal, velocity is 3.6 BV/h. This method can take off 84.3% of the pigment.(4) The influence of alcohol concentrations, concentration ratio, washing times on the efficiency of inspissation were studied in good single factor selecting and orthogonal experiment design. Pectin purity and gain ratio were used as index of the precipitated process. The results showed that concentrate multiple 4, alcohol concentration 70%; pH is 1.5, the optimal purity of pectin 81.65%.(5) Degree of esterification, moisture, ash, pH, galacturonic acid content were determined by GB standard, and all the parameters of sunflower head pectin was found to be in accord with the specification of GB. The solubility, viscosity, hot-stability and gel properties were compared sunflower head pectin with low methoxyl pectin.