Analysis of Volatile Components of Corn under Different Storage Conditions

In order to explore the quality change of corn during storage through the change of volatile substances,and find out the relevant characteristic volatiles,and provide a reference for corn safe storage. This experiment simulated different storage conditions and used electronic nose(E-NOSE)and headspace solid-phase microextraction(GC-MS)to detect volatile matter in corn,combined the principal component analysis method and the sample score chart to analyze the results. The results showed that the corn samples under different moisture temperature conditions had obvious differences in the radar chart with the storage period. The corresponding sensors showed that 15% high-moisture samples were more prone to moldy than low-moisture samples. The high-temperature and high-moisture samples were clearly distinguished from the rest of the samples on the principal component analysis chart after 3 months of storage,which indicated that the odor changed significantly. A total of 15 types of alcohols,25 types of aromatic hydrocarbons,23 types of aldehydes,59 types of esters,18 types of ketones,53 types of alkanes,22 types of olefins,and 27 types of heterocyclics were detected in the temperament test. Contributions were higher in esters,aromatic hydrocarbons,and alcohols. When the oxygen concentration was low,the volatilization of the esters was reduced,and the oxygen concentration had a small effect on alcohols and aromatic hydrocarbons. And only at extremely low concentrations of 2%~5%,the volatilization of 2,6-di-tert-butyl-p-cresol and 1-chlorodifluoromethoxy-4-nitro-benzene increased. When it was under low water conditions,benzyl alcohol had a large volatility. Alpha-pentyl-gama-butyrolactone,nonanoic acid and enal were more volatile under low temperature and low moisture conditions. Amides were more produced under high temperature and high moisture conditions. Vanillin had less volatility under high temperature and high moisture content. Both unsaturated olefins and enols increased with storage time. Electronic nose and GC-MS could effectively distinguish corn samples under different storage conditions,and could also judge the quality of corn by the amount of specific volatile substances. The two conditions of water and temperature had a greater impact on volatile substances. The effect of oxygen concentration was low. When the moisture content was lower than 13% and the temperature was lower than 20℃,storage under normal pressure could effectively prevent corn deterioration.