| Radish is an important original vegetables of China and the quality of products gets more attention. From the perspective of radish breeding, many traits that determine the quality are quantitative genetics and difficult to control, especially breeding research related with the flavor quality is less and limited the research process of radish quality breeding in some extent. This test uses solid-phase micro-extraction and gas chromatography-mass spectrometry to measure and analyze the main composition and accumulation of radish flavor substances in different varieties of radish and growth process, different growing seasons and storage, that can provide reference and theoretical basis for quality breeding radish and provide guidance and reference for the establishment of radish flavor quality evaluation system. The main findings were as follows:1. Comparing the differences in extraction of radish flavor ingredient by two extraction head which are PDMS/DVB and DVB/CAR/PDMS. The studies have shown that50/30um DVB/CAR/PDMS was the best SPME head to analyze radish flavor component which significantly better than65um PDMS/DVB head in the number, type and sensitivity of the compound extracted.2.The radish flavor compounds including seven substances which are isothiocyanates, alcohols, aldehydes, alkane, ketones, ethers and esters.There are three main flavor categories include aldehydes, ethers, isothiocyanates.The major flavor components is some sulfur-containing compounds and the content of isothiocyanates is largest proportion, but also the substance of glucosinolates hydrolysis from precursors of spicy and is the main substance to determine radish flavor.It can be used as the main indicator to measure radish flavor.3. From the four varieties "165×7"," Lu radish4"," Lu radish6","Han yin114","Lu radish4" is the largest number of flavor species,"165×7" is the least number of flavor species,"Lu radish6" is the highest content of flavor compounds and "Han yin114" is the least flavor number categories.There are some reasons cause different radish flavor in different varieties that are the differences in the presence of flavor ingredients and the exist of unique ingredients. 4. In different growth stages of radish,the flavor component has a large differences, aldehydes,isothiocyanates,as well as3-hexenal,l-penten-3-one, dimethyl disulfide,4-methylthio-3-butenyl isothiocyanate and total flavor showed a single peak curve in the process of growth and development of radish. It performance that they rise in the early fleshy root enlargement, and decline at swelling peak; methanethiol was "s"-type changes. It performance that it has a downward trend in the early fleshy root enlargement, and begin rebound at the post-enlargement, and it was gradually reduce when comes to harvest.5. In the spring alcohols and isothiocyanates, raphanin content is higher than in autumn, and the isothiocyanates which was in spring is about4times higher than autumn, the content of ketones and ethers substance in autumn are highter than in the spring, aldehydes has a little difference in the two seasons.6. In different storage period of "Lu radish4",flavor substances included10kinds of isothiocyanates, four kinds of alcohols, three kinds of aldehydes, two kinds of alkyl hydrocarbon, one kind of ketones, one kind of ethers. The kind of flavor substances changed little two months ago, but species decreased after. All material content tended to decrease in storage period, but the decline all kinds of different substances was different over time, aldehydes, ethers and isothiocyanates had the largest decline. |
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