RESUMO
Biofortification of crops with exogenous iodine is a novel strategy to control iodine deficiency disorders (IDD). The bioaccessibility of iodine (BI) in the biofortified vegetables in the course of soaking, cooking and digestion, were examined. Under hydroponics, the concentration of iodine in leafstalks of the celery and pakchoi increased with increasing exogenous iodine concentration, 54.8-63.9% of the iodine absorbed by pakchoi was stored in the soluble cellular substance. Being soaked in water within 8 h, the iodine loss rate of the biofortified celery was 3.5-10.4% only. More than 80% of the iodine in the biofortified celery was retained after cooking under high temperature. The highest BI of the biofortified vegetables after digestion in simulated gastric and intestinal juice amounted to 74.08 and 68.28%, respectively. Factors influencing BI included pH, digestion duration, and liquid-to-solid ratio. The high BI of the biofortified vegetables provided a sound reference for the promotion of iodine biofortification as a tool to eliminate the IDD.
RESUMO
Based on the study of typical selenium-rich soil in the middle area of Zhejiang province, the influencing factors of selenium contents were summarized. We found that the selenium contents were controlled by the geological background. It was much higher in Tangxi, Zhijiang, and Jinhua than in other geological background regions. In addition, the contents of selenium in soil under different land use types showed a great difference. The content in the dry land was much more enriched than that in the paddy field. Further research showed that selenium was closely related to soil organic matter because of its adsorption and fixation. Moreover, we found that the soil texture was another important influencing factor. Selenium contents increased with increasing content of clay in the soil.