The Technology Research Of Suppress Cooked Rice Retrogradation

With the development of economy,more and more people like eating out,central kitchen are more popular,at the same time,suppress the retrogradation of cooked rice becomes a core technology.When cooking rice,water swelling of rice then damage starch grains crystal structure,and starch gelatinization.During storage,cooked rice lose water and starch molecules changes from irregular to regular structure,which is called retrogradation.Retrogradation can lower the quality of cooked rice.There are two stages in retrogradation:short-term retrogradation and long-term retrogradation.Firstly,this research modeling for textural properties and sensory evaluation of cooked rice.Secondly using this model to optimize the condiments formula to prevent retrogradation of cooked rice.Lastly finding the best storage condition and contrast with retrogradation degree of cooked rice measure by RVA.This research contents are as follows:1.Optimization of cooking process for rice:the ratio of rice and water is 1:1.8,cooking time is 35min and soaking time is 35min.2.Modeling for textural properties and sensory evaluation of cooked rice.In this study,adding condiments:white rice vinegar,sugar and sesame oil or storage at different temperature to change eating quality and retrogradation degree of cooked rice and measure cooked rice by rice taste analyzer and texture analyzer then set model.The model are as follows.Studies are shown that the coefficient of association for texture properties and sensory evaluation is 93.5%and highly significant difference calculated by SPSS.Y=83.418-0.064*X₁-11.968*X₂-8.996*X₃-5.885*X₄-54.162*X₅-15.75*X₆+103.754*X₇+159.745*X₈-1.073*X₉3.This study shows that,when adding white rice vinegar,sesame oil and sugar as 7.50%,8.40%and 1.76%,respectively,cooked rice can get a best sensory evaluation,65.80,compared with cooked rice without condiments which is 51.82,increased by 26.97%.According to the model in this study,measuring the textural properties of cooked rice.Using sensory evaluation as response value.When adding 3 condiments at the same time,oil film can cover the starch molecular,to sustain the structure of starch molecular,and CH3COOH-,sugar can slow down the retrogradation,improve the sensory evaluation of cooked rice.4.The influence of variable temperature storage on cooked rice quality.There are two stages of storage cooked rice:cooling storage and constant temperature storage.According to the model in this study,measuring the textural properties of cooked rice.When cooling to 5?,the sensory evaluation of cooked rice is best.Cooked rice with condiments is 82.79,cooked rice is 64.26.Then storage under 15?,20?,25?.During storage,the sensory evaluation of cooked rice after rising first down and again rise and down.There are two peak value.When cooling to 5? then constant storage at 20?,the peak value can get in a later time than others.Its indicated that this condition can more suppress cooked rice retrogradation.