The Extraction And Pasting Property Of Different Sources Of Starch

Starch is used as a raw material for further processing and utilization. Pasting property contributes greatly to applied quality of corn starch and plays an important role in starch processing and application. A Laboratory-scale method isolating corn starch is studied by imitating industrial wet-milling, and is used to extract starches from corn hybrids. A Laboratory-scale method isolating wheat starch is studied by imitating industry, and is used to extract starches from wheat hybrids. Rapid Viscosity Analyzer(RVA) is adopted to analyze viscosity property, and Differential Scanning Calorimetry(DSC) is used to construe thermal property of starches, and Texture Profile Analysis(TPA) is used to analyze texture property of starches. In order to provide theoretics gist for industry utilization of starches, this paper focuses on the investigation of differences and relativities of viscosity property and thermal property and texture property of starches in normal corn(wheat) hybrids, the discussion of relativities of amylase and properties, the evaluation of pasting property of starches in their applied quality. The major results are as follows:1. The Laboratory-scale method isolating starch is studied.(1) The optimum conditions for corn are following: corn grains are steeped in 0.5% lactic acid and sodium bisulfite at 50℃for 36 hours. The launder gradient is 0.015cm/cm.(2) The optimum conditions for wheat are following: The dough is deposited for 20minutes, and is washed by ten times water. Starch liquid is centrifuged at 2000r/min for 15 minutes.2. The measure of amylose content indicates there is great difference in amylose content of normal corn (wheat) starch, and there is hardly any amylose in waxy corn starch.3. The pasting viscosity properties of starches are obviously different among different types of corn (wheat) hybrids. Analysis of correlation demonstrates that there are significant correaltions in pasting viscosity properties.4. The thermal properties of starches are not remarkably different except enthalpy among different types of corn (wheat) hybrids. Analysis of correlation demonstrates that peak temperature correlates significantly with origination temperature and cease temperature.5. The texture properties of starches are obviously different among different types of corn (wheat) hybrids. Analysis of correlation demonstrates that hardness correlates significantly with springiness and cease chewiness, and adhesiveness correlates with hardness and cohesiveness.6. The amylose content correlates significantly with peak viscosity in opposition, but hasn't significant correlation with other properties. Hardness and chewiness correlates significantly with peak viscosity and trough viscosity and final viscosity.