Study On The Storage Characteristics Of Paddy And The Quality Of Rice

Paddy is one of the main food crops,and also the source of food in most countries in the world.However,the deterioration of eating quality seriously affects the effective utilization of paddy.In this paper,Longjiang A,Longjiang B,Daohuaxiang,Qiutian and Xindao are as the research materials,and it explored the rice's quality characteristics,biochemical characteristics,edible quality,thermal characteristics and changes of thermal mechanical properties in different storage conditions;by analyzing the correlation between the indicators,this paper further expounds the reasons and mechanisms of the deterioration of rice eating quality.The main research contents and results as follows:1.By studying the changes in the fatty acid value and the fresh-aged index of five kinds of paddy under different storage conditions,the following conclusions were obtained: the fatty acid value of the samples reached the highest during the first 3months of storage,and then showed a fluctuating downward trend with the prolongation of storage time;The higher the storage temperature was,the bigger the fatty acid value of the samples is.At low temperature(15 ?)and quasi low temperature(20 ?),the fresh-aged index increases steadily with the prolongation of storage time,but the trend of change of the fresh-aged index is not obvious for the samples under high temperature(35 ?).Through the correlation analysis of fatty acids and freshness index of paddy samples,we can see that the relationship between the two indicators is high.2.The edible quality of rice under different storage conditions was investigated by using rice hardness tester,and the Relationship analysis was carried out in combination with the changes of biochemical indexes.The results show that:(1)With the prolongation of the storage time,the hardness of the non waxy rice increased,the viscosity,the balance and the elasticity of the non waxy rice were reduced;the hardness and viscosity of the glutinous rice increased,the balance andthe elasticity reduced.The hardness of the non waxy samples stored at 35 ? was higher than that at 15 ?and 20 ?,while the viscosity,balance and elasticity were lower than that at 15 ? and 20 ?.For the samples,the hardness and viscosity of the samples stored at 35? were significantly higher than those at 15 ? and 20 ?,and the balance and elasticity were lower than the samples at 15 ? and 20 ?.(2)With the prolongation of storage time,the amylose content and protein content of the sample increased,and the content of free amino acids increased first and then decreased;the different storage temperatures had little influence on the amylose content and protein content of the samples,and had greater influence on the content of free amino acids,the higher the storage temperature was,the higher the free amino acid content of the samples is.(3)The amylose content of non waxy rice samples has a significant positive relationship with the hardness value of sample,and has a negative relationship with viscosity,balance and elasticity;the content of damaged starch and free amino acid is negatively correlated with hardness and viscosity,and has a positive relationship with the balance and elasticity,and the relationship of protein content is not significant with the texture parameters of rice.The moisture content of the sample has a high relationship with the hardness,viscosity,balance and elasticity of rice,and the moisture content is negatively correlated with the hardness,and is positively related to the viscosity,balance and elasticity,and the relationship coefficient is large.There was a positive relationship between the amylose content and the protein content of the glutinous rice and the hardness and viscosity of rice.The content of damaged starch and the content of free amino acids were negatively correlated with the hardness and viscosity of rice,and had a positive relationship with the balance and elasticity,and the relationship was more significant.3.The changes of the starch thermal properties of five kinds of rice under different storage conditions were measured and the relationship analysis was carried out with the corresponding rice texture indexes.The results showed the To,Tp,Tc and?H values of non waxy rice increased with the prolongation of storage time,and thelower storage temperature had little effect on the To,Tp,Tc and ?H values.The To,Tp,Tc and ?H values of the samples were higher than those at the other two temperatures,but the changes in the storage temperature and the prolongation of storage time had no significant influence on the To,Tp and Tc values of the glutinous rice,but the ?H value of the glutinous rice increased with the prolongation of storage time.The ?H value of non waxy samples has a positive relationship with the hardness,and has a negative relationship with the viscosity,balance and elasticity.The ?H value of the waxy sample is negatively correlated with the hardness of rice,and has a positive relationship with the balance and elastic property,and the relationship coefficient is high.4.The effects of different storage conditions on the thermal mechanical properties of rice were compared and analyzed by using the Mixolab hybrid experiment instrument.The results showed that the value of C1,C1-Cs and Cs-C2 of the samples decreased with the gradual extension of the storage time,and the value of C1-C2 increased.In the stage of sample gelatinization,the initial gelatinization time and initial gelatinization temperature decreased with the prolongation of the storage time,while the value of C3 and C4 increased and the value of C3-C4 increased significantly,and the storage time and storage temperature had little effect on the value of C5 in the recovery stage of rice flour.There is a complex relationship between the value of C1,C1-Cs,Cs-C2,C3,C4,C3-C4,C5 and C5-C4 with the texture index of rice.