Study On The Ageing Mechanism In Rice Storage

As the main grain of more than half of the world's population,rice has great significance in extending its storage.In recent years,along with the rapid development of high-throughput technologies such as transcriptomics and proteomics,it has provided a systematic analysis method for the study of rice aging mechanism and functional proteins associated with aging,and for the aging of rice.The study of the mechanism provides a new technical method.This topic selects rice,which typically represents 4 varieties,from 12 types of rice in China.The artificial aging test and conventional storage test are used to analyze the change rule of the quality index in the storage process.The iTRAQ quantitative proteomics system is used to study rice.The molecular mechanism of aging during storage.The main research contents and conclusions are as follows:The changes of physicochemical and biochemical indexes of different varieties of rice during artificial accelerated aging and conventional storage were studied.The results showed that the physicochemical and biochemical indexes of four different varieties of rice LLY534,JLY1212,NX32,and YZX in the accelerated aging process had varying degrees of change.In the aging test,the moisture content of YZX rose to a maximum of 15.89 from the initial 12.44%.%,the moisture content in the NX32 increased from the original 12.54%to 13.37%after the test.The combined water content of YZX changed the most,falling by 3.26%.The fatty acid value in YZX increased from the initial 18.54 KOHmg/100g to 43.54 KOHmg/100g,and the trend was most obvious.The YZX change was the largest among the changes of thiol groups,from the initial 6.15 ?mol/g to 1.94 ?mol/g.In the biochemical indicators,the change trend of lipase is similar to the fatty acid value,in which the YZX with the highest fatty acid value reaches 13.97 KOHmg/g at the highest lipase,while the catalase content of YZX is lower than that of other varieties,and finally only 11.21 mg H2O2/g,a-amylase content except JLY1212,the other varieties have little difference.Taken together,YZX is a product that is not resistant to storage.The same as NX32 rice,but in the aging test process,the indicators are smaller than the YZX,indicating that it is more resistant to storage in the aging test than YZX,so choose YZX and NX32 for further routine storage experiments,in the conventional storage test,the storage characteristics of the two types of rice are basically the same as those of the aging test.Among them,the YZX has a higher moisture content,a lower bound water content,a higher fatty acid value,a higher lipase content,and a lower catalase content.The large range of changes in the indicator also confirms its immature storage characteristics in storage.The regularity of the flavor index of different rice varieties during regular storage was studied.The results showed that 182 and 189 flavor substances were detected in NX32 and YZX,mainly hydrocarbons,alcohols,aldehydes,ketones,acids,esters and ketones.Alcohols,acids,ketones and esters showed a downward trend,while aldehydes and hydrocarbons showed an upward trend.Explain that during the storage of rice,the formation of flavor is the result of the interaction of different volatile substances.For example,2-octyl-l-nonanol finally decreased to 1.61%in NX32,and finally decreased to 0.13%in YZX,and the initial contents of the main aroma compounds Mushroom Alcohol and n-decanol in NX32 were only in YZX.0.33%and 0.32%.Furfural with rosin and citrus aroma contained in aldehydes decreased by 0.8%in NX32 after storage and decreased by 2.58%in YZX.Fatty betelfuraldehyde decreased only by 0.09%in NX32 in YZX.However,it decreased by 0.52%.The rice varieties YZX that are not resistant to storage have a more pronounced change in flavor substances with the prolonged storage time,which indicates that the storage resistance of YZX during storage is poor and the substances in the body are prone to change.According to the results of the aging test,four rice varieties with different storage traits were selected as the research object.The iTRAQ quantitative proteomics system was used to study the proteomic changes of rice during storage.The results showed that there were 294 differentially expressed proteins in LLY534,108 differentially expressed proteins in JLY1212,and 151 differentially expressed proteins in NX32,and 321 differentially expressed proteins in YZX.The GO function analysis was performed on these four different rice grains to describe the molecular functions,cellular components,and biological processes of the genes,respectively.LLY534 classified by molecular function identified a total of 361 proteins,mainly ionic binding,catalytic action and molecular structure activity,according to the participation of biological processes can be divided into 1058 kinds of proteins,divided into 994 species by cell composition;JLY1212 A total of 137 proteins were identified based on their molecular functions.The major ones were ion binding,catalysis,and enzyme-regulating activities.According to participating biological processes,they were divided into 294 proteins,which were divided into 286 species by cell composition;NX32 According to the classification of molecular functions,a total of 182 proteins were identified,of which the main ones were ion binding,catalytic action,and molecular structure activity.According to participating biological processes,they were divided into 569 kinds of proteins,and divided into 449 kinds according to cell composition;in YZX press Classification of molecular functions A total of 379 proteins were identified,mainly ionic binding,catalytic action,molecular structure activity,and enzyme-regulating activity.According to participating biological processes,1044 proteins can be classified,and 1030 are classified according to cell composition.Combining the physicochemical,biochemical and flavor index changes of rice during the aging and storage processes,NX32(relative resistant storage)and YZX(relatively resistant storage)were selected as research objects for further bioinformatics analysis.The results showed that there were 18 different differentially expressed proteins in the aging process of these two rice varieties.The metabolic pathways of these differentially expressed proteins were mainly starch and sugar metabolism,glycolysis,tricarboxylic acid cycle and antioxidation.Inferred from the level of protein molecules storage rice in the storage process,because of its more intense respiration,resulting in faster consumption of organic nutrients,faster deterioration of quality,while not resistant to storage of rice sugar is accelerated decomposition,antioxidant The decrease in the expression of the protein or enzyme is more pronounced,resulting in a faster decline in the quality of the food during storage,which results in its inability to store.