| This paper mainly studies wheat quality indicators and volatile substances in different storage conditions,and Rhizopertha dominica volatile substances changing during cultivation.The moisture content of the wheat harvest in 2014 were adjusted to 12.5%,14.0%,and subpackaged in sealing bags stored for 270d,then stored in growth cabinet respectively at 4?,15?,35?.To detect the quality indicators such as moisture content,germination rate,color shading,falling index and dough properties,while using electronic nose and GC-MS to detect the relative content of volatile substances during storage.To detect the quality indicators such as thousand kernel weight and worm eaten rate during cultures,and gather statistics growth number and multiple at the end of cultures.While detected the eroded wheat volatile substances relative content and changes.The following conclusions are obtained through the experimental analysis:1.The quality of wheat was great influenced by storage time,temperature,initial moisture content of wheat.With the extension of storage time,the wheat quality is deterioration,the higher storage temperature and initial moisture content,the faster rate of quality deterioration.The correlation of storage temperature on the quality indexes of wheat was significant.Therefore,low temperature and low initial moisture content storage could prolong the storage period of wheat,and delayed deterioration rate of quality.Storage temperature and moisture content must be strictly controled during grain storage.2.The volatile components of wheat during storage were significantly changed.To detect wheat volatile components of storage early,middle and late period based on GC-MS,and divided the volatile components into seven categories,hydrocarbons,alcohols,aldehydes,ketones,acids,esters,heterocycles and other.To respectively gather statistics the volatile components classification relative content and the number of species components.As a result,the storage time significantly impacts to volatile components classification relative content.Storage temperature has a significant effect on the content of esters.The effect of initial moisture content on ketones,acids,esters,heterocyclic and other content significantly.With the extension of storage time,the relative contents of hydrocarbons,esters increased first and then decreased,alcohols,aldehydes,ketones,acids gradually increased.3.Using 20ml electronic nose headspace bottle to culture Rhizopertha dominica for about two months.To gather statistics final worm number of different insect density,as a result,with insect density increased,eventually worm number increased and growth multiple decreased gradually.Rhizopertha dominica growth is restricted due to feed wheat and culture vessel space is limited,while the test result has been certainly influenced.4.Using 2500ml culture vessel to cultivate Rhizopertha dominica for 70 days.To detect wheat quality index and take the sample pictures during the period of culture.To detect volatile components of eroded wheat based on electronic nose and gas chromatography-mass spectrometry(GC-MS).The analysis shows that with the increase of the density of the insect and the culture time,the corrosion rate increases and thousand kernel weight is gradually decreased.The odor information have bvious difference between cultured for 28 days(no infection)sample and other infection samples by electronic nose analysis.The GC-MS analysis shows that hydrocarbons,aldehydes content decreased obviously,esters,heterocyclic and other content increased significantly.Characteristic volatile components such as 2-pentanol,2-methyl-1-propanol and 2-pentanone were only detected in the eroded wheat volatile components,so preliminarily concluded that those components are produced by Rhizopertha dominica during the life activities.The volatile substance of esters is closly contact to gathered information biosynthesis of Rhizopertha dominica. |
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