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? ? Superfine powder due to its unique nature and widespread attention . Superfine powder preparation , properties and applications gradually become a research hotspot. This rice as raw material , the use of ultra fine milling of rice starch was prepared to obtain the nano- starch , and the preparation of a particle size of 50 ~ 5000nm rice starch morphology, molecular properties , crystal properties , thermal properties and gelatinization characteristics and physical properties were studied. The research projects, to make full use of rice resources , the development of new nano-materials, such as promoting the development of nanotechnology has great theoretical and practical significance . The main conclusions are as follows : 1. Ultra fine milled rice starch prepared more effective than jet mill and colloid mill pulverizing good . Suitable milling conditions: anhydrous ethanol as the media, media material ratio of 1:1 (w / w), the ball feed ratio of 5:4 (w / w), more than the number of balls of a large ball (Φ13mm): Small ball (Φ6mm) = 7:3, speed 500r/min. Below 100nm obtained by milling the rice starch. (2) the starch particles in the milling process to start the surface cracks , the crack then stripped from the starch , the starch particle size decreases , the gradual loss of the starch with a certain degree of aggregation is formed by the small size of the starch granules consisting of agglomerates . 3 in the milling process, the starch granule crystallinity decreases gradually after 20h milling crystalline structure disappeared. After milling 75h at room temperature can be gelatinized starch . Causes a certain degree of milling starch molecular chains , small molecule fractions increases. 4 decreases as the particle size of starch , starch iodine blue value , moisture content , dissolution rate , gel consistency , transparency , water-soluble protein content, starch hydrolysis rate and increase the stability of both , starch gelatinization lower gelatinization temperature and the maximum time , the maximum viscosity of the starch paste , final viscosity , and the return value appreciation landing is reduced , and the abrasive 20 ~ 30h , the changes of these parameters to flatten . 5 . Starch paste as pseudoplastic fluids. With the particle size decreases , lower consistency coefficient , flow index increases , approaching Newtonian fluid properties , and to enhance the stability of temperature and concentration . 6 . Starch elastic gel strength and viscosity are the particle size decreases with the decrease of starch . Small size starch poor storage stability at low temperature .
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