Study On Selenium Bio-Enrichment Of Garlic And Technology Of Garlic Oil Extraction

The study found that the function of selenium accumulation in garlic are better than other vegetables, so the effect of selenium accumulation and the form of selenium in garlic need further study. A field experiment of this study was to obtain selenium-enriched garlic, and then comparison of the selenium content and form between selenium-enriched garlic and normal one. The preliminary effect of selenium accumulation in garlic have been studied in our research. In addition, the optimum extraction conditions of garlic oil were obtained through an orthogonal design by distillation and supercritical CO2extraction methods. The oil yield, activity and composition of two kinds of garlic oil have also been studied to value the different extraction methods. The results are as follows:1、The selenium content of selenium-enriched garlic samples significantly increase, selenium contents of the selenium-enriched garlic were significantly and linearly increased by selenium application, with total selenium in garlic and stems being raised from0.047ug/g and0.043ug/g of control up to0.200-0.834ug/g and0.291～0.962ug/g, respectively. Selenium application stimulated the absorption and accumulation of selenium in rice and stems.2、The form of inorganoselenium and organoselenium in selenium-enriched garlic and normal one were detected by HPLC-ICPMS method. There are three main forms of selenium compounds exist in two kinds of garlic. It is seleno-DL-cystine (SeCys2), methyl-selenocysteine(MeSeCys) and SeⅣ. The content of any selenium compounds in selenium-enriched garlic are higher than normal sample.3、The main factors influencing extraction garlic oil yield by distillation method ranged in following order:PH value> temperature> time> Fe2+concentration. The optimized parameters for garlic oil obtained by distillation method were:PH value of6.5, Fe2+concentration of10mmol/1, temperature of45℃, time of60min. The highest yield of distillation of garlic oil reached0.362%.4、The main factors influencing extraction garlic oil yield by supercritical CO2extraction method ranged in following order:extraction pressure> CO2flow rate> extraction temperature> extraction time. The optimized parameters for garlic oil obtained by supercritical CO2extraction method were:extraction pressure of25MPa, CO2flow rate of30L/h, extraction temperature of45℃, extraction time of1h. The highest yield of extraction garlic oil by supercritical CO2extraction method reached0.428%.5、Antioxidant capacity of two kinds of garlic oil obtained by different method were evaluated by scavenging DPPH radical and the lipid peroxide inhibition. Garlic oil obtained by supercritical CO2extraction exhibited higher ability of scavenging DPPH radical and the lipid peroxide inhibition. Both of them had some antioxidant capacity.6、The chemical compounds of two kinds of garlic oil were analysed by GCMS. The result showed that the major sulfur compounds are the same. Diallyl trisulfide (C6H10S3) is the highest contents sulfur compound in both garlic oil. The quantity of the chemical compounds in garlic oil obtained by supercritical CO2extraction are less than other one, while the composition of garlic oil obtained by distillation is more complex.