Study On The Forms And Characteristics Of Organic Selenium In Selenium-enriched Sweet Potato

Eating selenium-enriched food is the most convenient and effective method for humans and animals,and it can directly supplement the selenium in animals.In the method of using exogenous selenium fertilizer to cultivate selenium-rich crops,plants can effectively convert exogenous selenium into their own organic selenium compounds.1.In this experiment,the microwave digestion-HG-AFS method was used to quantitatively analyze the total selenium content of selenium-enriched sweet potato and its components and soil.The results showed that the selenium content in sweet potato leaves was always higher than that in stems,roots and soil environment,and the selenium content per unit mass of selenium-enriched sweet potato freeze-dried powder was always higher than the total selenium content in fresh sweet potato samples.Therefore,crops can be made into dehydrated freeze-dried powder,which can more effectively enhance the selenium supplement effect of food and increase the added value of agricultural products.2.Sweet potato with selenium applied from external sources has a significant reduction in the concentration of harmful elements arsenic,cadmium,lead,and mercury compared with the blank control group,showing an antagonistic effect.Therefore,the enrichment of selenium in crops can effectively reduce the concentration of enriched harmful elements in crops and play a role in reducing the harm of harmful elements.3.After orthogonal design optimization,the optimal conditions for extracting polysaccharides from selenium-enriched sweet potatoes are:when the material-to-liquid ratio is 1:30,ultrapure water is used as the extractant,and the extraction is performed at a constant temperature of 50℃ under ultrasonic environment for 60 min,and centrifuged.Then carry out the second extraction and combine the concentrated extracts.The soluble polysaccharide selenium content in the selenium-enriched sweet potato under the optimal cultivation conditions accounted for 25.8%of the total selenium content of the selenium-enriched sweet potato root tuber freeze-dried powder.4.The optimal conditions for extraction of soluble protein in selenium-enriched sweet potato after orthogonal design optimization are:0.15 mol/L NaOH aqueous solution for extraction,control the material-to-liquid ratio to 1:30,and shake the extraction in a constant temperature water bath at 40℃ for 90 min.The soluble protein extracted from the optimal level of selenium-enriched sweet potato contains selenium content of 1.27 μg/L,and the selenium yield is 34.4%.5.Combining the extraction effect of soluble polysaccharide and soluble protein in selenium-enriched sweet potato and the selenium content,it can be concluded that the sum of selenium content in polysaccharide and protein in selenium-enriched sweet potato exceeds 50%of the total selenium content in the root tuber.Since organic selenium is more easily absorbed and utilized by the human body,vigorously developing organic selenium in selenium-rich crops has great application prospects.6.Comparing the proteolysis effect of several proteases on selenium-enriched sweet potato,it is found that the best enzymatic hydrolysis effect is when 10 mg alkaline protease is selected,and the enzymatic hydrolysis rate can reach 87.4%.7.Using HPLC-ESI-MS combined technology,qualitatively analyze the structure of selenoamino acid extracted from selenium-enriched sweet potato.Judging by the mass-to-charge ratio and the characteristic peaks of selenoamino acid hand shape,the selenium-enriched sweet potato also contains selenohomocysteine and selenomethylmethionine,but the response peak height is lower,which may be the reason for the lower content.