Studies On The Effects Of Process Methods On The Structure And Properties Of Rice Flour

Rice, rice noodle and extruded rice stick were the main material in this paper. Theproperties of them before and after some processing were studied to investigate the effect ofstewing, extrusion puffing and acid&heat moisture treatment on the rice flour. The contentand results of the research included the following aspects:1. Series of samples were taken from the rice noodle production line and tested in thelaboratory. The basic content of the rice flour were almost the same, no significant changeswere observed in the infrared spectrometer. The gelatinization degree were increased by twostewing process. The gelatinization degree of the final products was up to89.25%. X-raydiffraction (XRD) was utilized to study the crystallinity of the samples, and the gelatinizationdegree and the crystallinity showed a good linear relativity. This result could be used to testthe gelatinization degree substitute for the traditional enzyme hydrolysis methods.2. Study on the effects of extrusion puffing process on rice silk fragments’ properties hadshown that: the crude fat content reduced, the sugar content increased significantly for highlevel gelatinization and degradation. Strutrue was further ruined, and the solubility and theswelling ability increased significantly. The beginning gelatinization temperature andmaximum viscosity was lower. The digestion rate of the processed rice was further improved.3. The rice flour was modified by acid&heat-moisture treatment and series of sampleswere prepared by changing technological parameters to investigate the effect of acid&heat-moisture treatment on the properties of the rice flour. The results indicated that proteincontent reduced, reducing the pH, improving the moisture content, increasing the reactiontemperature, prolonging the reaction time or the use of low-temperature cooling couldincrease the binding protein content. The processed rice flour granules were damaged lightlyby acid&heat-moisture, crystallinity reduced. No clear change was observed in infraredspectrometer, even changing the conditions in laboratory. DSC showed that the endothermicpeak of rice starch moved backward, and the absorption enthalpy (△H) decreased, pasteviscosity curve showed that the samples had low viscosity, it was a smooth, parallel to theX-axis baseline when treated by extreme condition. The digestion rate of the rice floursamples was much higher than unhandled sample, the relation between starch hydrolysis and time followed the first-grade kinetic equation well, and the nutritional segments differed aftertreated in different conditions.