Study On The Correlation Of Characteristic Of Waxy Rice Flour And Rice Dough

In order to determine the key indicators which mainly influence the quality of waxy riceflour, the composition and properties of ten kinds of waxy rice flour and starch were studied,and the correlations of characteristics and edible quality of waxy rice flour were also studied.Besides, process conditions of waxy rice dough were researched to determine the optimumprocess conditions. The purpose was to provide theoretical basis for choice of the rawmaterial and quality improvement of products in actual production.Firstly, the basic composition of the ten kinds of waxy rice flour including moisture,crude ash, crude protein, starch and crude fat were measured. And the physicochemicalproperties such as particle size, gel consistency, swelling capacity and damaged starch content,solubility, water absorption, freeze-thaw stability and gelatinization characteristics were alsoresearched. The coefficient of variation of ash in materials of different suppliers and batcheswas higher (>25%), while other indicators relatively low. Difference of stability offreeze-thaw was significant (>100%). The coefficients of variation of solubility, peakviscosity, disintegration value and retrogradation value were higher (>25%). Swellingcapacity and water-holding capacity of waxy rice dough were also higher (>20%).Coefficients of variation of other physicochemical properties were relatively low.Secondly, the quality of waxy rice dough made of different raw materials was evaluated,and correlation on waxy rice characteristic and rice dough was also analyzed. Correlationsamong protein content, peak temperature with the frost crack rate of the waxy rice doughwere positive and significant. Starch content showed negative and significant correlation withthe frost crack rate. Particle size showed negative and extremely significant correlation withthe water lose rate of waxy rice dough, while gel consistency, solubility and water-holdingcapacity of waxy rice dough showed negative and significant correlations.The retrogradationvalue showed positive and extremely significant correlation with the water lose rate. Swellingcapacity, peak viscosity and retrogradation value had significantly positive correlations withtransparency of soup after cooking. The correlations among starch content, fat content,particle size, swelling capacity and gelatinization characteristics with TPA properties of waxyrice dough were significant. Correlation analysis showed that starch content and properties ofwaxy rice flour especially the gelatinization characteristic, particle size and swelling capacityhad great influence on the edible quality of waxy rice flour.Thirdly, physicochemical properties of waxy rice flour stored at room temperatureincluding acidity, freeze-thaw stability and gelatinization characteristics were researched.Acidity increased with the increase of storage time. Freeze-thaw stability was improved. Thechange rules of gelatinization characteristics of different samples were different. Peakviscosity was relatively increased with the increase of storage time, and the storage time ofreaching the maximum peak viscosity may be different.Fourthly, properties of waxy rice starch and amylopectin were researched, including thetransparency, consistency, freeze-thaw stability and gelatinization characteristics of starchgels and blue value, maximum absorption wavelength and average chain length ofamylopectin. Difference of stability of freeze-thaw was significant (>100%), while other indicators relatively low. Blue value of amylopectin was0.09~0.12, and the maximumabsorption wavelength was521~536nm, which were both within the scope of itscorresponding theory. Correlation analysis showed that amylopectin showed negative andsignificant correlation with the frost crack rate of the waxy rice dough and significantlypositive correlation with cohesiveness. The pasting temperature showed positive andsignificant correlations with the water lose rate and hardness, while breakdown value showedsignificant negative correlation with hardness.The retrogradation value had negative andsignificant correlation with resilience. The freeze-thaw stability of starch and the maximumabsorption wavelength of amylopectin both showed significantly negative correlations withcohesiveness.Lastly, process conditions of waxy rice dough were researched. Through single factorexperiment, the amount of water addition, fineness of raw materials and fermentation timewere studied, which had effect on rice dough quality. Orthogonal experiment was designed onbasis of the single factor experiment. Taking the frost crack rate as evaluation index, theoptimal process conditions were as follows: fineness of waxy rice flour was120mess,fermentation time was30min and the amount of water addition was90%(measured by drybasis).