| Selenium(Se)is an essential micronutrient for human beings.If selenium intake is insufficient,it might cause many diseases such as Kashin-Beck disease.China is one of the most serious selenium-deficient areas in the world,with about 72%of the land area lacking selenium.Wheat is the main food crop in China,accounting for about 30%of the daily energy intake,and the selenium enrichment ability of wheat is strong.Therefore,wheat is a good carrier of selenium supplementation in China.However,the average selenium content of wheat grains in China is about 64.6?g·kg-1which is far from satisfying the selenium demand for the wheat-based population.Selenium content of wheat grain can be improved effectively by soil application or foliar spraying.The wheat processing has an important effect on the selenium content in flour,for example,the flour yield is closely related to the selenium content in flour.However,the majority of the current studies focus on field selenium strengthening research,rarely from farmland to food processing chain research.In this study,five high quality wheat were used as test material,and foliar selenium fertilizer was sprayed at three different growth periods:jointing stage,booting stage and filling stage.After that,the wheat grain was powdered,and the changes of selenium content and the effect of field selenium strengthening on flour quality were analyzed.Then the selenium-enriched flour was used as the test material to optimize the process of selenium-enriched bread and to develop selenium-enriched bread.The main conclusions of this experiment are as follows:(1)In this study,52 selenium-rich wheat literatures were reviewed.According to the results,the most effective way to increase the selenium content in wheat grain is to apply selenium or foliar selenium fertilizer,and the most suitable concentration of selenium in soil is 0.25 mg·kg-1respectively.Foliar fertilization optimum concentration is 40 mg·L-1.(2)Compared with Se content in wheat grains of the control group(147.60?g·kg-1),the selenium content of the Se-spraying fertilizer group was significantly increased(729.13?g·kg-1).The changes of selenium content in grain of four different treatments were as follows:filling stage>jointing stage>panicle stage>control group.After spraying selenium fertilizer,the grain selenium content of five different wheat increased 374.19%,393.24%,421.51%,388.33%and 398.85%,respectively.(3)Compared with Se content in wheat flour of the control group(124.80?g·kg-1),the selenium content of the Se-spraying fertilizer group was significantly increased(654.17?g·kg-1).The loss rate of selenium was lower than that of other elements in grinding process.The changes of grain selenium content loss rate in four different treatments were as follows:filling stage>jointing stage>panicle stage>control group.After spraying selenium fertilizer,the loss rate of selenium in seed grain decreased significantly compared with that in control group,and there was no significant difference in selenium loss rate in three different spraying periods.The loss rate of selenium was 15.68%,13.07%,13.16%and 12.11%,respectively.Among them,the selenium content of New wheat No.26 flour was higher than that of the other four varieties,and the of selenium fertilizer spraying group reached 833.5?g·kg-1during filling period?(4)Compared with the selenium content(113?g·kg-1)of bread(New wheat No.26),the selenium content of selenium-rich bread(the fertilizer spraying group in filling stage of New wheat No.26)was significantly increased to 585?g·kg-1(Increased by 422 per cent). |
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