Fine Structure and Rheological Properties of Starch.

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A systematic research on the rheological properties of starch was carried out, and the relationship between the fine structure and rheological properties of starch was investigated.1. Molecular characteristics and thermal properties of the tropical starches. It was obtained one fraction of amylose and some fractions of amylopectin from six kinds of starches by gel filtration, after debranched using isoamylase. Difference to samples of the thermal properties was recognized.2. The viscoelasticity of starch gels from kuzu and sweet potato could be analyzed using a four element model. It was observed from the results of sensory evaluation that kuzu starch gel demonstrated elasticity, less susceptibility to crumbling, stickiness and ability to melt in the mouth, whereas sweet potato gel was chewy and more susceptible to crumble.3. Study on the static and dynamic viscoleasticity, and spinnability was carried out of the three kinds of starch paste from glutinous rice, waxy corn and cassava which were in a semi-solid state showing rheological properties but not in gel. 4. General physicochemical properties of tropics origin cocoyam starch has also been conducted. At the same time, the dynamic viscoelasticity in the process of gelatinization, spinnability of the starch paste, and characteristics of the gel were studied in comparison with sweet potato. 5. Classification to the physical properties of starch gels and study on the correlation between sensory evaluation and mechanical measurement was carried out. 6. The static and dynamic viscoelasticity in the gelatinization to retrogradation process under certain condition of cassava and potato starches sugested the difference in the mechanism of retrogradation between the two samples.