Starch Fraction Isolation And Characterization Of The Interaction With The Surfactant

Linear amylose and highly branched amylopectin are the major components of starch, differences in their molecular structure result in the different physical and chemical properties and application performance, thus the separation of amylose and amylopectin becomes a basic process of deepening the starch application.Amylose and amylopectin of potato were separated with the methods of complexing regant separation and purified, then their purity and molecular structures were characterized by iodine-blue method and laser light scattering. The results show that with thymol and butanol as the complexing agent, the blue value of obtained amylose and amylopectin and the corresponding maximum absorption wavelengths are 1.03 and 640 nm,0.19 and 560 nm respectively, and their yields can reach up to 90.0% and 61.5%. Further dissolution experiments show that both of the two fractions have a better solubility in 90% DMSO, the main interaction among molecular chains is repulsive force. When they were dissolved in KOH solution, the maximum absorption wavelength of starch-iodine complex shift of the 10 to 30 nm, and the molecular chains are seriously scission in the dissolution process, its average molecular weight and gyration radius is lower one or two order of magnitude, and this time, the interaction force between the molecular chains of amylose change into a mutual attraction, and molecular chains of starch in a tight state.In view of the fact that starch and collector are often copresent during the mineral processing, the interaction between starch and collector dodecylamine(DDA) was studied by UV-Vis spectroscopy, surface tension, fluorescence spectroscopy (FS), atomic force (AFM), infrared spectroscopy (FTIR) and thermal analysis (TG). The results show that DDA can not only absorbe on the outside of starch to form pre-micelle with starch through polar amino group by hydrogen bonding, but also, its non-polar hydrocarbon chain can enter into the hydrophobic spiral cavity of starch from the end of starch chain regions by the hydrophobic force. Therefore, the blue value of starch can been reduced in a very low concentrations of DDA, and its corresponds of the maximum absorption wavelength blue shift, especially in the amylose-DDA system. DDA and starch will form pre-micelle when the concentration of DDA is moderate, and with the concentration of DDA continue increase, DDA micelles will also form vesicles and wrapped up the starch chains.