Study On The Preparation Technology Of Selenium-rich Malt

Selenium, which moderate intake is of great significance to human health, is a kind of essential trace elements for human beings. Selenium in inorganic form is more poisonous, easily causing selenosis. The toxicity of organic selenium compounds with higher bioavailability is far lower than that of inorganic selenium compounds. However, organic selenium content in the natural food is small, generally insufficient to meet the body’s normal needs, so using animals, plants, microorganisms and so on to achieve the bioconversion of selenium has become an important research direction. In this article, barley is chosen as a carrier to absorb inorganic selenium and then transform them into organic selenium, selenium-rich process and technology conditions of sodium selenite recycling are optimized, they can provide the basis data for commercial process.Selenium is analyzed by using Ultraviolet spectrophotometry in this article, it is found that the maximum absorption wavelength of selenium standard solution is 334 nm, optimization analysis conditions are: complexation acidity pH=2, complexation time is 40 min, the dosage of 1% o-phenylendiamine solution is 2.5mL, dosage of 5% EDTA solution is 2mL; Se4+ content of selenium-rich malt in the range of 0~2.3μg/mL conforms to the law of bill, Standard equation is A=0.20778c+0.00369, the correlation coefficient is 0.99986; The average recovery rate is 98.04% and the RSD is 4.4%; The precision(RSD=2.7%)、reproducibility(RSD=1.4%) and stability(RSD=0.80%) of the method are good。This method has the advantage of simple operation, fast measurement, high sensitivity, a smaller toxicity and so on, especially applicable for the determination of trace element selenium in malt.It is found that Xiyin 2 barley variety is with good germination rate, bud growth rate and rich selenium content by examining different barley varieties. On this basis, selenium content as index, the technology conditions of selenium-rich malt is optimized. The main factors that affect barley germination are: soaking concentration, soaking temperature, soaking time, germination time. The optimum germination conditions by single factor experiment are determined as follows: Na2SeO3 concentration is 200mg/L, soak time is 8h, soaking temperature is 25℃, germination time is 4days. In this condition, the total selenium content of rich selenium malt is 30.41μg/g, while the organic selenium content is 29.50μg/g.It is found that only a small amount of sodium selenite solution is absorbed after seed soaking, so recycling residual sodium selenite is the key to reduce product cost. Based on germination rate and selenium content as indicators, this article studies the effect of recycling of sodium selenite solution on product performance.It is found that cycling three times, barley germination rate, total selenium and organic selenium content change little, while cycling four times, each index decreases significantly; It is through the analysis found that colony count in solution is rising along with the increase of cycle index, and it rises significantly when cycling four times. On the above basis, the Na2SeO3 solution is dealt with the operation of microwave sterilization after being preliminary recycled for three times. The influence of two factors including heating power and heating time on the sterilization effect is studied. At the same time, microwave sterilization is compared with water bath sterilization. The results are as follows: under the condition that the microwave power is 700 w, sterilization time is 30 s, the sterilization effect is best and the sterilization efficiency is highest. Microwave sterilization has the advantage of short heating time, high fatality rate, uniform heating, easy operation which is better than the water bath sterilization; microwave sterilization experiment later, further improvement test on Sodium selenite solution is took, the average germination rate of seeds are up to 86.48%. After the preliminary recovery and microwave sterilization, production cost of 1kg of malt powder decreases from 28.65 yuan to 19.71 yuan.