Methods To Determine The Gelatinization Properties Of Grain And Correlation Studies

Based on RVA before arrival,grain viscosity research was done by using Brabender viscometer,and the current standards by Brabender viscometer measured value as the main basis of quality discrimination,and after the advent of RVA,with its unique advantages in small sample volume,convenient widely everyone to use,but the data can not be used phenomenon in judging,it is the urgent need for the exchange between the two instruments.It is intended to verify the relationship between the measured data of Brabender viscometer and RVA data,and to determine their exchange formula,which will be of some guiding significance for scientific research and production practice.In this study,10 samples of rice,corn and wheat were selected,then adjust moisture content of 10%,12%,14%,16% and 18%and shred into powder,the powder particle size,rice and corn was divided into 40 mesh,80 mesh and 120 mesh,wheat is divided into 120 mesh,160 mesh and 200 mesh size.Then RVA was used to determine the gelatinization viscosity,and the best test method was selected according to the variation coefficient.Then by Brabender viscosity measurement,the best test condition was selected.According to the two methods to the best test condition,the correlation and linear relationship between two kinds of instruments for measuring viscosity of three kinds of cereals were analyzed.The experimental results are as follows:1.10 rice samples were determined by RVA,the peak viscosity,the minimum viscosity,the breakdown value,the final viscosity and the setback value of the samples had small difference when the moisture content is 10% to 16%.The particle size has great influence on it.The four indexes of the peak viscosity,the breakdown value,the final viscosity and setback value all increase with the decrease of particle size,while the minimum viscosity decreases with the decrease of particle size.According to the coefficient of variation,the pasting characteristics of rice can be obtained by RVA.The condition is that the control grain size is 80 mesh,and the moisture content is within 10% to 16%.It can be directly weighed and not converted.2.10 corn samples were determined by RVA,the peak viscosity,the minimum viscosity,the breakdown value,the final viscosity and the setback value of the samples were increased withthe decrease of the particle size,and the coefficient of variation was the smallest at 80 mesh size.When the moisture content is 10% to 16%,the five indexes of the peak viscosity,the minimum viscosity,the breakdown value,the final viscosity and the setback value all increased with the increase of water content,When the water content is 14%,the coefficient of variation was small.Therefore,when determining the pasting properties of corn by RVA,the granularity is controlled by 80 mesh and moisture content need to be converted according to the standard.3.10 wheat were determined by RVA,the peak viscosity,the minimum viscosity,the breakdown value,the final viscosity and the setback value of the samples had small difference when the particle size is 120 mesh,160 mesh and 200 mesh.The coefficient of variation is smaller when the particle size is 120 mesh and 160 mesh.The five indexes of the peak viscosity,the minimum viscosity,the breakdown value,the final viscosity and the setback value all increased with the increase of water content,and the coefficient of variation is small when the moisture content is 14% and 16%.Therefore,when RVA was used to measure the pasting characteristics of Wheat,the grain size of wheat should be controlled between 120 and160 mesh,and the water content in the range of 14% to 16% does not require direct conversion.4.The moisture content of rice,corn and wheat was less affected by Brabender viscometer.For rice and corn,the five indexes of the peak viscosity,the minimum viscosity,the breakdown value,the final viscosity and the setback value were increased with the decrease of the particle size,and the coefficient of variation is smallest when the particle size is 80 mesh.So 80 mesh should be controlled when rice and corn are measured by Brabender viscometer.For wheat,the five indexes of the peak viscosity,the minimum viscosity,the breakdown value,the final viscosity and the setback value changed smaller with the decrease of particle size.And the coefficient of variation is smallest when the particle size is 160 mesh.Therefore,160 mesh should be controlled when measuring wheat by Brabender viscometer.5.For rice,the relation between the measured Brabender values y(BU)and RVA values x(RVU)relationship is: the highest viscosity y = 0.1965 x-402.85;the lowest viscosity y =0.2806 x-453.29;the dilute slack values y = 0.1463 x-40.46;the final viscosity y = 0.2481x-621.36;the setback values y = 0.2422 x-202.62.