Preparation And Characterization Of YAM Maltodextrin And Dialdehyde Starch

In this paper, the properties of starch obtained from the yam residues, which have been used to isolate bioactive ingredients with various methods, were full investigated. The preparation technology of maltodextrin and dialdehyde starch(DAS) using yam starch as substrate was optimized. And the physicochemical properties of dialdehyde yam starch with different aldehyde content were studied. The main contents of this thesis were as follows:1. The native yam starch and starch in yam residues which have been used to isolate bioactive ingredients with alkali and enzyme treatments were isolated and characterized. The physicochemical, morphological, thermal, crystalline and pasting properties were evaluated by scanning electron microscope (SEM), differential scanning calorimetry(DSC), X-ray diffractometry(XRD), and Brabender Viscograph. The influences of different treatments on the properties of starches were analyzed in detail.2. The process conditions using yam starch as substrate to produce maltodextrin were studied. On the basis of discussing the effect of enzyme supplementation, enzymolysis temperature, enzymolysis time and concentration of the starch solution on DE value of production, the preparation technology was optimized by using Response Surface Analysis. The results showed that the best process conditions to manufacture maltodextrin by enzymolysis method are as follows:the concentration of the starch solution is30%. the enzyme supplementation is40-60U/g. the enzymolysis temperature is95℃as well as the enzymolysis time is40-60minutes. And under this condition, the DE value of maltodextrin is between12.43-19.87.3. The process conditions of dialdehyde yam starch was investigated. On the basis of discussing the effect of reaction time, reaction temperature, reaction pH, concentration of the starch solution, and the ratio of sodium periodate to starch on aldehyde contents of DAS, the preparation technology was optimized by using A four-factor three-level orthogonal experiment. It was found that the optimal conditions were reaction time5hours, reaction temperature40℃, reaction pH4.0, concentration of the starch solution20%and the ratio of sodium periodate to starch was at1.1:1. And under this condition, the aldehyde of DAS is97.63%.4. The morphological, crystalline and thermal properties of DAS with different aldehyde contents were characterized and the influences of different aldehyde contents on these properties were analyzed in detail.