Study On Preparation And Characterization Of Acetylated Distarch Phosphate

With corn starch as raw material, the acetylated distarch phosphate was prepared by using acetic anhydride for esterification reaction and sodium trimetaphosphate for cross-linking reaction; the compound modified corn starch was prepared by wet process and its modified order, physical properties and process conditions was investigated. The rheology of dough with modified starch was studied by farinograph and extensograph. Application of distarch phosphate in noodles was also investigated.The effects of four factors on crossed-linking degree was studied by single factor experiment. Based on orthogonal experiments, optimal conditions were acquired. The results were as follows:starch-water mixture40%(w/w), concentration of sodium trimetaphosphate2.5%, reaction2.Oh, pH10.5and temperature45℃.The sequnce of distarch phosphate was first cross-linked by sodium trimetaphosphate then esterified by acetate ester. Based on the single factorial experiment and the orthogonal experiment, the optimal cross-linking conditions were as follows:starch-water mixture40%(w/w),The degree of crosslinking is1.8mL, Acetyl anhydrides6%, time1.5h, and temperature25℃. The optimal esterifying conditions were as follows:starch-water mixture40%(w/w), concentration of sodium trimetaphosphate2.5%, pH10.5. time2.Oh, and temperature45℃The results of Scanning Electron Microscope (SEM) showed that, the effects of esterifying and cross-linking reaction to the starch granule were slight, but granule polymerization increased after modified. due tothe effect of chemical reagents, particle surface with varying degrees of depression and fold. Physical properties of modified starch granule were determined, the results were as follows:paste transparency reduced with the cross-linking degree increase; retrogradation stability and freeze-thaw stability became escalate with the cross-linking degree increase, paste transparency, retrogradation stability and freeze-thaw stability of modified starch become better with the esterifying degree increases. Compared with native starch. cross-linking starch and esterified starch, paste transparency, retrogradation stability and freeze-thaw stability of dual-modification starch was the beast.After determination of farinograph characteristics, the result showed that elasticity, stability, shear resistance force and gluten strength were better then the dough add with normal corn starch witch the dough add with dual-modification starch. The result by extrude test show that flour force increase by add the dual-modification starch, with the effect of cross-linking, maximum stretching obstruction was improve, add acetate groups make the increase of resilience better than normal corn starch. After add acetylated distarch phosphate in noodles, its broken bars rate, cooking loss, luster, palatability, elasticity and tenacity become better than before, so acetylated distarch phosphate can ameliorate quality of noodles.