Selenium Speciation In Se-enriched Bamboo Shoots Of Phyllostachys Violascens And Phyllostachys Pubescens

Selenium(Se), presented in plants with a variety of species, is an essential trace element for human body. Bamboo shoots are popular food in Asia, but there is no report on selenium species in Se-enriched bamboo shoots. In order to study selenium species in Se-enriched bamboo shoots, Se-enriched shoots of Phyllostachys violascens and Phyllostachys pubescens shoots were cultivated by cavity injection method, i.e., injecting Na2SeO3solution of different concentrations into culm cavity. Total selenium was measured using inductively coupled plasma spectrometry (ICP-MS) and the profile of selenium species were determined using high performance liquid chromatography (HPLC) ICP-MS. The results showed as follows:1. The total selenium content in rhizosphere soil of Phyllostachys violascens was0.50-0.67mg/kg, and there was no correlation between total selenium content in soil and the injection concentration of NaiSeO3solution. It is indicated that clum cavity injection method is environmentally friendly.2. After the injection of NaiSeO3solution, all bamboo shoots were selenium-enriched, and the content of total selenium increased, and then decreased when the injection solution concentration increased. The total selenium in shoots of Phyllostachys violascens reached a maximum of7.55mg/kg(DW) when the injection solution concentration was2400mg/L, and the total selenium in shoots of Phyllostachys pubescens reached a maximum of10.45mg/kg (DW) when the injection solution concentration was3200mg/L. It was concluded that the best injection solution concentration for Phyllostachys violascens and Phyllostachys pubescens were2400mg/L and3200mg/L, respectively. The ability of selenium-enriched in Phyllostachys pubescens was about2times of Phyllostachys violascens.3. The total selenium contents decreased from tips to basal parts of shoots of Phyllostachys violascens.4. A new HPLC-ICP-MS method for determinating selenium species in Se-enriched bamboo shoots was developed. SeMet、SeCys2、MeSeCys、Se(IV) and Se(VI) can be seperated by using Hamilton PRP-X100anion exchange column (250mm×4.1mm×10μm) with a5m mol/L citric acid buffer solution (pH4.72, adjusted with20%ammonia) as mobile phase.5. Enzyme extraction (pronase E) was better than water extraction for pretreatment of selenium species analysis.6. There were at least5species in the shoots of Phyllostachys violascens and Phyllostachys pubescens and the organic species consisted most parts of total selenium. The main parts of organic species was SeMet, accounting for87.3%and92.9%-96.9%in non-biofortication and biofortification products of Phyllostachys violascens, respectively, and82.7%and91.9%-95.5%for Phyllostachys pubescens, respectively. The percentages of inorganic selenium content in non-biofortication shoots were higher than those of biofortification ones.7. The loss rate of total selenium during procedure in dried shoots, cooking dried shoots, Shimizu canned shoots were12.0%,23.8%and18.5%for Phyllostachys violascens. For different species, the loss rate of SeCys2was the highest, followed by MeSeCys, and the SeMet loss rate was the lowest. The processing procedure of bamboo shoots have little effects on selenium contents, and Se-enriched products will be a new way to solve the human selenium deficiency problem.