Interaction Mechanism Of Ternary System Of Rice Protein,Rice Starch And Water

As a global food crop,rice has become the basic energy source for nearly half of the population in the world.All kinds of rice products are also popular with more and more people.Improving the processing characteristics of rice and delaying the decline of product quality caused by the retrogradation of rice starch has become a hot topic in recent years.The present studies mainly focus on adding some exogenous substances to rice starch to explore the effects of these exogenous substances on the gelatinization and retrogradation properties of rice starch.There is no systematic study on the interaction between rice components.In this paper,rice protein,the second major component in rice,and water which is essential in the process of processing were selected as variables to explore their effects on the properties of rice starch gelatinization and retrogradation.Firstly,rice protein was added into rice starch,and then the gelatinization process of rice starch under the same water content was characterized.The results showed the addition of rice protein resulted in higher peak viscosity,lower trough viscosity and lower setback value of rice starch during gelatinization.Moreover,rice protein made rice starch gelation faster,and the gel had higher hardness and strength.However,it had no significant effect on the thermodynamic properties of rice starch.During retrogradation,rice protein restricted the migration of water in the starch gel,inhibited the decrease of the spin-spin relaxation time,slowed down the formation of ordered structure,the gel had no obvious shrank on the 7 day,and the microstructure was more homogeneous.Secondly,we prepared different concentrations of rice starch suspension to characterize the gelatinization properties of rice starch.The results showed that the decrease of water content led to the increase of the end temperature of starch gelatinization,and the changes of rheological properties caused by the change of starch structure during gelatinization by rheometer were easier to observe.During retrogradation,when the ratio of solid to liquid was 1:4 and 1:2,the decrease of the spin-spin relaxation time and the shrinkage in volume were obvious.Based on the analysis of the properties of rice starch during retrogradation,a water distribution model and a water migration model of rice starch during retrogradation were proposed.Finally,we studied the gelatinization and retrogradation properties of rice starch under the different water content and rice protein added.The results showed that the addition of rice protein reduced the increase of the end temperature of starch gelatinization.During retrogradation,rice protein showed the characteristics of inhibiting retrogradation under high water content and promoting retrogradation under low water content.The study of the interaction between the components of rice can explain the changes of rice properties in the processing process,and guide the research of the related technology of rice products.