Synthesis And Application Of Cross-linking Waxy Wheat Starch Octenyl Succinate

The single and compound modified starch was prepared under the condition of usingwaxy wheat starch as material, sodium trimetaphosphate and methyl octenyl succinate asmodifier, and was studied theirs processes, properties and structure to provide better qualityimprover for food industry particularly for frozen food, and broaden the application scope ofwaxy wheat starch.First, the waxy wheat starch were separated and purified, and then they were used as rawmaterial of modified starch. When they were modified by sodium trimetaphosphate, andstudied the effect of different reaction conditions on the sedimentation volume, such asreaction time, pH range, reaction temperature and the usage of sodium trimetaphosphate. theorthogonal test showed the optimum conditions were: reaction time4h, pH9.75, temperature45℃, sodium trimetaphosphate9%, the sedimentation volume of product prepared underthis condition is2.20mL. When the material was modified by methyl octenyl succinate, andresearched the effect of the amount of methyl octenyl succinate, starch concentration, reactiontime, reaction temperature and pH range on the degree of substitution (DS) of the modifiedstarch, response surface analysis was done with design expert software and the optimisticcondition of synthesizing was the amount of methyl octenyl succinate7%, starchconcentration34.7%, time7.82h, temperature32.7℃, pH8.82, the degree of substitution ofthe product prepared under this condition was0.0212. When the material was modified bysodium trimetaphosphate and methyl octenyl succinate, the test found that the sedimentationvolume of the sodium trimetaphosphate modified starch had little effect on the degree ofsubstitution (DS) of the compound modified starch, so the compound modified starch can beprepared according to the needs of the industrial during the actual production.Secondly, the physical and chemical properties of products were measured, includingtransparency, retrogradation, viscosity, freeze-thaw stability, shear resistance, acid resistance,solubility, the impact of freeze-thaw stability in different media and the plication in yoghurt.The results showed that the compound modified starch have better performance comparedwith single modified starch and native starch, and are more suitable for industrial production.Application test in the yogurt, the emulsifying-thickening effect of the compound modifiedstarch are better and the most appropriate addition is0.5%.Finally, the results of infrared absorption spectroscopy (IR) and magnetic resonance spectrometer (NMR) showed that the different modified groups were connected to themodified waxy wheat starch; X-ray diffraction analysis displayed that the modified areas indifferent modified starch were mainly in non-crystalline, and had no change in crystallinestructure of A type of waxy wheat starch; scanning electron microscope (SEM) showed thatthe waxy wheat starch granules were smooth oval originally, but some of the surface of starchgranules appeared different shades of holes after being different modified; small-angle x-rayscattering (SAXS) analysis indicated that the electron density difference of the modified waxywheat starch by different modifier was caused to change.