Research On The Functional Components Of Eurotium Cristatum

During the process of "fungi growing", Eurotium cristatum played an important role to formate the special quality and health function of Fuzhuan brick tea. According to the relevant reports that Eurotium cristatum can produce a variety of metabolites in the growth process. In this research, Eurotium cristatum was taken as the experimental strain which was separated from Fuzhuan brick tea of Shaanxi. The growth condition of the mycelium of Eurotium cristatum was studied and the dynamic model of mycelium growth of Eurotium cristatum was established using the liquid submerged fermentation. Meanwhile, the stability of the pigment which was the functional component of Eurotium cristatum was also studied and the separation and purification of yellow pigment and the infrared spectrum of each content was analyzed. The results were illustrated as follows:The research on the cultivate condition of the spore of Eurotium cristatum: the wheat bran was taken as the culture medium and the yield of pigment was taken as an indicator to investigate the cultivate conditions of the spore of Eurotium cristatum. The better cultivate condition of Eurotium cristatum was obtained by the single factor test:1:1.5 of water ratio,28℃ of culture temperature,4.5 of media pH value,5% of inoculation amount,12% of sample capacity. The optimize growth condition of Eurotium cristatum by orthogonal test was obtained:1:1.8 of water ratio,28℃ of culture temperature,4.5 of media pH,5% of inoculation amount,10% of sample capacity. Under the condition, the yield of pigment was up to 3.1%.The research on the liquid cultivate condition of the Eurotium cristatum:the PDA was taken as the culture medium and the dry weight of mycelium was taken as an indicator to investigate the nutrient substances and the best cultivate condition of liquid culture of Eurotium cristatum. In the orthogonal experiment, the culture medium was:20% of potato,4% of sucrose,0.3% of ammonim nitrate,0.15% of KH2PO4,0.03% of MgSO4·7H2O,100 mL of water, the dry weight of mycelium can be reached 0.48g/100mL under this culture condition. The optimize growth condition of Eurotium cristatum was:28℃ of culture temperature,120 r/min of shaking speed,5.0 of pH value,25% of sample capacity,7 days of fermentation time and 5 days of seed culture time.The research of the extraction process of Eurotium cristatum:the optimum conditions of the extraction process of pigments was obtained with Box-Behnken design under response surface methodology. The major elements of the effects on extraction of pigment of Eurotium cristatum were found by single factor experiment. Microwave-assisted extraction process of pigment was optimized by response surface design. The result showed that optimum extraction technology of yellow pigments was:solvent-solid ratio 1:38, extraction temperature 56℃, microwave power 457W. Under these conditions, average yield of pigments was 10.08%. And the measured value was consistent with the predicated value, which revealed the applicability of RSM to the optimization of extraction of pigments from Eurotium cristatum.The research of stability of yellow pigment of Eurotium cristatum:with the different light sources, temperature, pH, metal ions, redox agents, food additives and acid as the study factors,the degradation rate of the yellow pigment as the indicator. The study on stability of the yellow pigment showed that the yellow pigment did not tolerate high temperature. Light, especially sunlight, showed in an obvious loss of stability of the pigment. Better stability of the pigments was observed at the range of pH 2 to 8. Most metal ions had no effects on the stability of pigment except that Fe3+, Fe2+, Cu2+had severe undesirable effect. The different concentration of sugar and a high concentration of Vc fortified the tone of pigment, while sodium benzoate, hydrogen perodide and inorganic acid obviously degraded the tone of pigment.The research of the separation and purification of yellow pigment and the analysis of infrared spectrum:the HPLC chromatogram showed that the pigment consist of four components and the component of retention time 5.823 min had occupied the highest content. The infrared spectrum showed that the four components have roughly same curve but each substance has different absorption bands. The yellow pigment appears the characteristic peak of hydroxyl, methyl, carboxyl, amino and glycoside bond, eater bond. While each substance include different degrees with aromatic skeleton, therefore, the pigment contained functional groups and it’s structure was very complicated.The research on the dynamic model of mycelium growth of Eurotium cristatum. During the fermentation, the mycelium and the pigment of Eurotium cristatum had appeared rapidly rising then stable trend and the pH and the DO had appeared rapidly decline then stable trend. The mycelium growth of Eurotium cristatum accorded with Logistic equation and the the dynamic model was obtained by the 5 L fermenter as followed:...