Selenium-enriched Characteristics And Morphological Analysis Of Grapes

Selenium can prevent diabetes mellitus,cataract,arthritis and other diseases,but at present most areas of China are selenium deficient areas.How to supplement selenium scientifically and effectively has become the focus of attention.In this paper,selenium-rich grapes were cultured by foliar application of selenium,and the total selenium content and soluble selenium content in selenium-rich grapes were determined by inductively coupled plasma mass spectrometry（ICP-MS）.The selenium-containing amino acids in selenium-enriched grapes were analyzed by HPLC-ESI-MS to understand the selenium-enriching ability of grapes and the distribution of different forms of selenium in grapes.1.Cultivation of selenium-enriched grapes and determination of seleniumThe selenium-enriched grape was cultured by spraying selenium fertilizer in the range of0²00 mg/kg to the grape leaf surface,and the selenium-enriching property was studied.The determination of selenium in selenium-enriched grapes was carried out by ICP-MS.The results showed that the selenium content in the grapes increased first and then decreased with the increase of the selenium gradient.2.Study on the speciation analysis in Se-enriched grapesThe extraction temperature and extraction time are the main factors affecting the selenium content of each form:35℃and 60 min for H₂O,HCl,Tris-HCl,PBS,45℃and 40 min for NaOH..According to the optimal extraction conditions,quantitative analysis of different forms of selenium in grapes can be obtained:NaOH>HCl>Tris-HCl>PBS>NaCl>H₂O.3.Extraction of selenoprotein and selenium polysaccharide from selenium-enriched grapesThe extraction conditions of selenium protein and selenium polysaccharide from selenium-enriched grapes were optimized by single factor experiment.The relationship between selenium protein and selenium polysaccharide content in selenium-enriched grapes and the gradient of selenium application,as well as the relationship between gliadin and glutenin and the gradient of selenium application were studied.The results showed that the optimum conditions for extracting soluble protein were as follows:ratio of material to liquid1:15,extractant 0.1 mol/L sodium hydroxide,extraction temperature The optimum conditions for extracting soluble polysaccharides were as follows:the ratio of material to liquid was 1:20,the extraction temperature was 70 C,the extraction time was 1 h and and times of extraction of twice.The contents of selenium protein,selenium polysaccharide,gliadin and glutenin in selenium-rich grapes increased first and then decreased with the increase of selenium concentration.4.Antioxidant analysis of selenium-enriched grapesThe antioxidant activity of selenium-enriched grapes was studied by four antioxidant systems in vitro,the results showed that the scavenging rate of DPPH free radicals,hydroxyl free radicals,superoxide free radicals and reducing power of selenium-enriched grapes were positively correlated with the gradient of selenium application.5.Analysis of Selenium Amino Acids in Se-enriched Grapes by HPLC-ESI-MSThe three amino acids of selenomethionine（Se-Met）,selenocystine（SeCys₂）and selenocysteine（SeCys）were analyzed by HPLC-ESI-MS.The results showed that With the increase of selenium content,the content of selenoamino acid increased first and then decreased,and when the concentration of selenium reached 160 mg/kg,the content of three seleno amino acids reached the maximum.