Study On Extrusion Characteristics Of Different Brown Rice Varieties

The rice is shelled to obtain brown rice,which is a complete seed of rice.The nutrition is rich in active substances.However,due to the high fiber content of the brown rice cortex,the processing and utilization are limited.According to statistics,the processing and utilization of brown rice is less than 1% of the total rice production in China.The instantaneous high temperature,high pressure and expansion effect of the extrusion process can not only change the structural characteristics of the material,but also solve the problems of poor taste and digestibility of brown rice,and also better preserve the nutrient components,providing new possibilities for the processing and utilization of whole grain brown rice.In this paper,the effects of extrusion treatment on the quality characteristics of brown rice flour were studied.The effects of the main chemical components of different varieties of brown rice on the expansion characteristics of brown rice were discussed.The correlation between the main chemical components of brown rice and the quality characteristics of extruded flour was determined.It is expected to predict the quality characteristics of extruded flour through the main chemical components of brown rice,and then clarify its processing applicability,and provide a basis for the application of extruded brown rice flour.1.Optimization of brown rice expansion process: based on the single-factor test of process parameters(material moisture content,screw frequency,feed rate and expansion temperature)and product expansion degree as indicators,uniform test design is carried out,and the optimized process parameters are The moisture content of the material was 11%,the screw frequency was 21 Hz,the feeding frequency was 29 Hz,the expansion temperature was 95 ?,and the product expansion degree was determined to be 5.33.Using the multiple regression model,the order of the influence of process parameters on the product expansion degree is determined as follows: expansion temperature > screw frequency > material moisture content > feeding frequency.2.Compared with the raw brown rice flour,the extrusion treatment makes the thermal stability of the brown rice flour stronger,the shear thinning degree of the paste is weakened,not easy to regenerate from aging,and the freeze-thaw stability is improved.The scanning electron microscopy showed that the extrusion process made the structure of the brown rice flour fine and porous.3.The correlation analysis between the main chemical components of different brown rice and its extrusion properties(gelatinization degree,expansion degree,water absorption index,water solubility index)showed that the degree of gelatinization of the product and the total starch content of the raw brown rice There was a significant positive correlation(P<0.05).Both the expansion degree and WAI were significantly positively correlated with the amylose content of the raw brown rice(P<0.01),and significantly negatively correlated with the total starch content.4.The correlation analysis between the main chemical components of different varieties of brown rice and the quality characteristics(gelatinization,thermal and texture characteristics)of extruded brown rice flour.There was a significant negative correlation between the disintegration value and the total starch content of the raw brown rice during the gelatinization process.The retrogradation value was significantly negatively correlated with the total starch content of the raw brown rice,and positively correlated with the amylose content(P<0.01).There was a significant negative correlation between peak temperature and total starch content(P<0.05);the correlation between the texture indexes of the whole powdered dough and the main components of the raw brown rice was not significant.Therefore,after the extrusion of the brown rice varieties with low total starch content and high amylose content,the obtained extruded flour has good thermal stability and is not easy to age back.Therefore,it is possible to predict the suitability of the extruded flour after extrusion and the selection of the raw materials for the extruded flour of different uses by measuring the content of the main components of the raw brown rice.5.Partial replacement of wheat flour with extruded brown rice flour,the effect of the amount of extruded brown rice flour on the quality of mixed flour.There was a significant negative correlation between the addition amount of puffed brown rice powder and the DSC characteristic value(P<0.01).The addition amount of extruded brown rice flour was significantly positively correlated with water absorption rate,dough formation time and weakening degree(P<0.01),and had a significant negative correlation with stability time and silty index.The addition of extruded brown rice flour showed a significant positive correlation with the hardness,viscosity,adhesiveness and chewiness of the dough(P<0.01),and the correlation with cohesiveness and elasticity was not significant.The addition of extruded brown rice flour can significantly improve the water holding capacity of the frozen dough,and can significantly improve the freeze-thaw stability of the dough.The freeze-thaw stability of the mixed powder is best when the addition amount is 25%.