Detection Of Principal Nutrition Constituents In Foxtail Millet And The Preparation Of Foxtail Millet Tea

Chapter 1:The characteristic of foxtail millet nutrition constituents, include protein, lipid, starch, amino acids, minerals and vitamins, are depicted in brief. The detection method and application of foxtail millet are reviewed in detail.Chapter 2:A total of fifty-nine foxtail millet varieties were collected from different places in China and they were unshelled. Determining the values of principal constituents (crude protein, crude lipid, total starch, amylose, fifteen kinds of amino acids, vitamine E and selenium) in 59 kinds of foxtail millet by chemical method. The content of total starch reach up to 75.0% and crude fat is only 3.66%. The content of crude protein is 15.36% and glutamic acid has the highest content in amino acids. Vitamine E and selenium are also rich in foxtail millet.Chapter 3:In order to establish an analytical method of controlling foxtail millet quality rapidly and precisely with lower cost, shorter time and higher efficiency, scanning the near-infrared spectra of foxtail millet and combining them with the chemical values, the analytical equations were developed using partial least squares (PLS) regression and cross validation for multivariate calibration, study the potential of using the Fourier-near infrared reflectance spectroscopy(FT-NIRS) to estimate the principal constituents in foxtail millet. The results showed that it is feasible to analyze the main components except lysine, vitamin E and selenium. The best model obtained was for relative crude protein content, with an R2 of 0.979, a RMSECV of 0.342% and the RPD value of 5.14.Chapter 4:Foxtail millet was selected as raw materials to the preparation of natural foxtail millet tea, the processing method of natural foxtail millet tea was studied and the optimum conditions were ascertained. The best conditions are as follow:the soaking duration is 1h, steam time is 7min, baking temperature and time is 150 centigrade degree and 30min respectively. Under these conditions, natural foxtail millet tea has better flavor and color than others.Chapter 5:The change of nutrition composition and volatile oils were determined in machining process simultaneous. The aroma compounds in foxtail millet tea were extracted by solid-phase micro-extraction and analyzed by gas chromatography-mass spectrometry (GC-MS). The results showed that the content of crude protein and total starch keep stable, at the same time crude fat decrease gradually. Each processing stage of foxtail millet tea had the different influence to the different aroma components. There was a significant reduction in total area counts of volatile compounds after soaking and increase after steaming and baking. The esters and aldehydes compounds were reduced and alcohols increased at last.