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Study On Preparation And Propertis Of Esterified Cross-linked Porous Corn Starch

Posted on:2013-12-03Degree:MasterType:Thesis
Country:ChinaCandidate:Y M YangFull Text:PDF
GTID:2231330377458280Subject:Food Science
Abstract/Summary:PDF Full Text Request
The porous starch is prepared from corn starch by two enzymes method underultrasonic-microwave. The sodium trimetaphosphate cross-linked porous starch isprepared by reaction porous starch with sodium trimetaphosphate underultrasonic-microwave. The cross-linked porous starch as raw materials in themicrowave reacts with octenyl succinic acid methyl ester, and then esterificationcross-linked the porous starch is prepared. This paper would provide a theoreticalbasis for technology, nature, structure, conduct research of porous starch.Firstly, in the basis of single elements and the oil absorption rate of the testindicators, by orthogonal experiments, under ultrasonic-microwave preparation ofcorn starch optimum conditions is determined: microwave power150W, ultrasonicpower400W, temperature56℃, α-amylase enzyme dosage for8U/g, glucoamylaseand α-amylase activity ratio is6:1, the citric acid buffer pH5.4, time45min. In thebasis of single elements and the settlement of plot of the test indicators, by orthogonalexperiments, under ultrasonic-microwave preparation of corn starch optimumconditions is determined: pH10, reaction time40min, microwave power95W,ultrasonic power130W. In the basis of single elements and the degree of substitutionof the test indicators, by orthogonal experiments, under ultrasonic-microwavepreparation of corn starch optimum conditions is determined:8%of the starch octenylsuccinic acid methyl ester dosage, microwave power110W, reaction time45min, pH9.5, reaction time45min.Secondly, the analysis of cross-linked the esterification porous starch rheologicalproperties found that: the esterification cross-linked the porous starch transparency isdepressed signicantly; Freeze-thaw stability increased; Thermal stability incresed;anti-retrogradation aging deterioration; Degree of swelling and solubility hasincreased; accumulation density is lower than the original corn starch,but higherthan cross-linked porous starch and porous starch. The absorption rate of cross-linkedthe esterification porous starch is96.5%(129%) higher than corn starch, 21%(29.6%)higher than porous starch,6.5%(8%)higher than cross-linked porousstarch.Finally, analysis of structure of the starch samples: new groups of peaks ofinfra-red spectrogram indicate that modified radical of porous starch have beenconnected. Analysis of SAXS indicates corn starch change significantly after differentmodifier agent; Analysis of SEM indicates that the surface of esterification porousstarch granules doming more small particles,roughness concentration increased, andthe inner of holes formed the part of small particles, small particles increase aroundthe holes; a little damaged starch fragments reform new particles by cross-linkedesterification. Analysis of DSC shows that the thermodynamic properties andcrystalline grain structure of the modified porous starch had a certain degree ofchange.
Keywords/Search Tags:porous starch, ultrasonic, microwave, sodium trimetaphosphate, octenylsuccinic acid methyl ester
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