| A series of modern detecting techniques were used to systemicly characterizing structural parameters and functoional propteties of starches from different hybrids of maizes and wheats, and commercial starches from different botanical sources. These techniques included Laser Particle Analyzer for granule size distribution and average diameter, X-ray Diffractometer for relative degree of crystallinity, Rapid Visco-analyzer for pasting properties, Differential Scanning Calorimeter for thermal properties, Texture Analyzer for texture profile analysis, and Scanning Electronic Microscope for morphology of starches. Pearson correlations among various properties were analyzed in order to provide some guidance for value-added products development and expanding utilization fields of starch. We had optimized preparation conditions of cationic starch by semi-dry process using Response Surface Regression methodology. On the base of above work, we had deeply explored the reaction mechanism of starch cationization by semi-dry process. The major results of the paper were as follows.1. Many correlations among various properties of maize starches were observed. The gelatinization temperatures of starches were significantly correlated to pasting temperature and cohesiveness. Significant negative correlations were found between the gelatinization temperatures and adhesiveness, amylose content. The peak viscosity was positively correlated to trough viscosity, breakdown, final viscosity and setback, and negatively correlated to pasting temperature. We can predict the increasing or decreasing relationships between structures and functionalities according to the correlations. The results may provide theory foundation for starch selection in application and quality breeding of maize.2. Many correlations among various properties of wheat starches were observed. The peak gelatinization temperature was positively correlated to onset gelatinization and conclusion temperature, and negatively correlated to hardness. The amylose content was significantly correlated to hardness and cohesiveness, and negatively to breakdown. The peak viscosity was positively correlated to trough viscosity, breakdown, final viscosity and setback, and negatively correlated to cohesiveness. The average diameter was positively correlated to peak viscosity, trough viscosity and final viscosity. The correlations between structure and functionality of wheat starches differed from that of maize starches, the relationships between structure and functionality of starches from different botanical sources should be studied individually.3. Many correlations among various properties of different botanical starches were observed. The amylose content was significantly correlated to final viscosity and setback. The peak gelatinization temperature was significantly to onset temperature. Positively correlations between peak viscosity, breakdown and average size were observed. The gelatinization enthalpy was positively correlated to peak viscosity and breakdown. Pasting temperature was negatively correlated to the degree of crystallinity. The correlations can provide some information for special starch material selection and new idea for quality breeding and metabolism adjustment of corps containing starch.4. Based on the correlations between structure-functionality of starches from different maize hybrids, different wheat hybids and different botanical sources, we can regard amylose content, average granule dinamerer, peak viscosity, and peak temperature of gelatinization of starch as characteristic parameters for quality evaluation and starch selction in various application fields.5. Preparation conditions of cationic starch by semi-dry process was optimized. Within the experimental conditions studied, a maximal reaction efficiency was obtained at molar ratio of NaOH/CHPTMA 1.85, the temperature of 61℃, moistur conternt of 20.49%, and reaction time of 4.49 hr.6. We endowed the peak gelatinization temperature with characteristic parameters of starch for semi-dry cationisation.7. The relative crystallinity of starch increased with the increase of acid-hydrolysis time. The cationization reactivity of acid-thinned starch by semi-dry process significantly decreased originally, and later increased slightly with the increase of relative crystallinity. The cationization reactivity of starch by semi-dry process not only related to the content of the amorphous region but also to the position of starch molecule in the starch granule.
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