Study On The Difference Of Rice Quality,Fungal Flora And Mycotoxins In Different Storage Periods

There will be more losses in the storage of rice paddies,causing great economic losses to the country and affecting the reserves and supply of food.It is helpful to ensure the safe storage of rice by studying the change of quality,the change of mold flora and the content of mycotoxin during the storage period of rice and systematically analyzing the correlation performance between these indexes.Therefore,this study measured the rice quality index,fungal flora and mycotoxin contents in different storage years in the grain depot,and then analyzed the correlation between these indexes to reveal the quality and safety differences of stored rice.The main results of this article are as follows:1.By testing the main quality indicators and volatile substances of rice in different storage periods,it was found that the fatty acid value and amylose content of the rice stored in 2013 were significantly higher than those of the rice stored in other years;the content of protein and polyphenol oxidase in rice in 2018 was significantly higher than that in other years.The moisture content of all samples is below the safe level.A total of 54 volatile substances were detected,including 19 types of alkanes,1type of olefins,6 types of aromatic hydrocarbons,7 types of alcohols,2 types of aldehydes,2 types of ketones,14 types of acid esters,and 3 types of heterocyclics.In the study,it was found that the content of specific volatile substances in rice samples was related to the storage year,because the aldehyde and ketone substances in rice storge in 2013 were lower than those in 2017 and 2018,and only in 2017 could olefin components be detected.However,there was no significant correlation between volatile substances and quality indexes of rice.2.Through the separation and purification of dominant molds in different storage periods of rice,a total of 16 molds were identified.Aspergillus blanc and Aspergillus niger were the dominant molds detected in all samples.The unique dominant mold of rice in different storage years may be related to the production of unique volatile substances in rice.The longer the storage year of rice,the less the number of molds.Through the correlation analysis of the number of molds with quality indicators and volatile compounds,it was found that there was no significant correlation between the number of molds and quality indicators.3.Through the study on the content of mycotoxins in rice in different storage periods.The contents of aflatoxin B₁?AFB₁?and ochratoxin A?OTA?in stored rice from 2013 to 2018 did not exceed the national limit value,indicating that the stored rice was well maintained.Through correlation analysis,it can be concluded that only in the rice stored in 2016,the toxin content was significantly correlated with the protein content?p<0.05?,there was no significant correlation between toxin content and mold quantity and other quality indexes.