Study Of Selenium-inriched Optimization On Agriculture And Heat Dehydration On Selenium Preservation In Se-enriched Salicornia Bigelovii Torr

Selenium (Se) is an essential nutrient in the human diet.Se deficiency may lead to many diseases.The adult Se intake in China is substantially lower than Chinese Preventive Medicine Center's recommended.However,the form of Se in plant has higher bioavailability.Therefore, the use of vegetable as a vector of selenium enrichment is an appropriate choice.This thesis studied the Se enrichment in Salicornia bigelovii Torr.Then,a study on the effects of vacuum microwave drying and vacuum frying processing on Se content were done by using the Se-enriched Salicornia bigelovii Tor.The results could provide the basic knowledge for application and the guidance in the industrialization of functional food containing trace element.Firstly,Salicornia bigelovii Torr was selected as the selenium enrichment test material for studying the rules of inorganic selenium intake in vegetable.The Se enrichment method was spraying Na2SeO3 solution with different concentration,different times and different pH.The results show that within certain ranges of spraying concentration,selenium content enriched was linearly correlated with the concentration of Na2SeO3.Spraying several times could improve selenium absorption in Salicornia bigelovii Torr with the lower concentration of Na2SeO3 and adequate adjustment of pH.Spraying of Na2SeO3 solution led to higher selenium accumulation at later growth phase of Salicornia bigelovii Torr.At the end,RSM had been used for optimization on agriculture.The best Se-enrichment parameters were fixed.Secondly,Se-enriched Salicornia bigelovii Torr was selected as sample in microwave vacuum drying.Effects of pretreatment and the microwave vacuum drying on selenium content were studied.The results showed that organic Se content reduced by 17 % at 4℃of the cold storage.In blanching process,the loss of total selenium reached to about 28% in Se-enriched Salicornia bigelovii Torr.4-6 h and 0.09 MPa are optimum desalting conditions. 20 % maltodextrin was beneficial to preservation rate of organic Se in the vacuum microwave drying.The microwave power,drying time and initial moisture content of material had a significantly effect on preservation rate of Se.The recommended processing of vacuum microwave drying was done with the pressure 0.09 MPa,microwave power 329.6±5 W and initial moisture content 75 % of material,as the moisture content could reach to below 5% and the preservation rate of total Se could reach to about 43 %.Finally,effects of vacuum frying processing on Se content were studied.The results showed that frying temperature, frying time and initial moisture content of material were the most significant factors for the degradation of Se.In the end, the optimum vacuum frying technological conditions was studied. According to orthogonal experiment, the optimum vacuum frying technological conditions were frying temperature 100℃,vacuum degree 0.090MPa,frying time 9min and initial moisture content 75% of material.At the same time,dynamic model of Se degradation was studied. Se degradation agreed with dynamic model of the Boltzmann equation with the apparent activation energy 49578 J·K-1·mol-1.