| Ethyl pyruvate is a kind of colorless and transparent liquid. It is very volatile at common temperature, and has sweet floral fragrance with fresh. It has the function of disinfection, whitening effect, and can be widely used in food, medicine, cosmetics and other industries. Ethyl pyruvate can be used to protect flowers, fruits and vegetables for their freshness during the transport. It is not only has no effect on the plants but also can increase the smelling of aroma, compared with the low-temperature preservation. However, ethyl pyruvate is volatile at common temperature. If not being protect, it will volatilize quickly during a short period of time and can not keep fresh for a long time. In this thesis, we did some research on the microencapsulation of ethyl pyruvate, and made the final product have the function of release-controlled which can last long for sterilization and fresh-keeping, and it also improve the usage efficiency and expand the application range. At the same time, we established a method of Reverse HPLC to detect the content of ethyl pyruvate. The Paper used "air stream tiny Hole" and spray drying methods to microencapsulate the ethyl pyruvate. By selecting a suitable wall material, surfactant and changing the content of emulsion, we confirmed the final process. The main results are as follows:1. The formulation for preparation of ethyl pyruvate microcapsule using "air stream tiny hole" is sodium alginate concentration2.5%, the best proportion of wall material, sodium alginate, and core material, ethyl pyruvate, is1:1,emulsifying agent is0.2%tween80+0.1%stearin, CaCl2concentration is2.0%. The proper spray drytechnical parameters is meterial flow speed20ml/min. Encapsulation efficiency of ethyl pyruvate is up to59%in this condition.2.When spray dry method is used to prepare ethyl pyruvate microcapsules, proper wall material combination is sucrose, Hi-cap100and gum Arabic. The best emulsion formula for spray dry ethyl pyruvate:sucrose/Hi-cap100/gum Arabic is4:3:1, core/wall is1:1.5, concentration of emulsion is50%. The optimum technological condition on spray dry method is:entering air temperature160℃, air outlet temperature80℃On this conditon, ethyl pyruvate encapsulation efficiency can get98%and it has better test reproducibility. 3. The assay was performed on a Tigerkin ODS column(4.6mm×250mm,5μm) by UV derector at the wavelength of220nm with mixture of Acetone and Acetonitrile(3:2) as the mobile phase at the flow rate of1.Oml/min. The sample dissolved in aqueous solution. After ultrasound extraction, broken the wall of microencapsulated by the mobile phase, then it was filtered. Finally, it was injected to be determined by HPLC. Microencapsulated powder surface was smooth, no collapse, no cracks. The amount of ethyl pyruvate was linear with its area over the range from0.3mg-1.8mg/mL(R2=0.9992), the average recovery was98.05%(RSD=1.17%). The present method is simple and the result is accurate for determination of ethyl pyruvate in microencapsulated. |
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