| Natural vitamin E is one of the most important substances maintains the functions of the body, as the fat-soluble vitamins,which has been used as an additive in many foods.Both the biological activity and safety,natural VE is much better than synthetic VE,so natural VE is used more and more as one of food or feed additives. However, natural VE is vulnerable to be damaged when exposed to oxygen or UV irradiation long-term,this caused to be more difficult to be preserved and utilized in the food and feed. Micro-capsule technology is one of important technologies in food processing which can protecte and reduce the sensitive material directly contact with the external environment and keep stable. This paper studied microcapsulation formula and spray-drying of the, spray-drying technology and properties of nature VE microcapsule and exosyndromed the properties of the product.High content of natural VE oil microcapsules were prepared by pressure spray drying. Through examining the encapsulation efficiency and stability of emulsion of three composite wall materials:gelatin-corn syrup, modified starch-corn syrup, sodium caseinate-corn syrup, the modified starch-corn syrup (6:0.9,W/W)was selected to be the best wall material for microencapsulation of natural VE, the total amount of compound emulsifiers is 3%. The optimal formula obtained for microcapsulationg of natural VE oil:wall material modified starch-corn syrup (6:0.9, W/W), core material of natural VE 62.5%, the total amount of compound emulsifiers 3%. The effect of spray-drying conditions on the Quality of microcapsules was studied, the optimum process conditions is:homogenization pressure 35Mpa, inlet air temperature 170-180℃, blast temperature 90～95℃, feed flow rate 25 mL/min, solids concentration 50%.Sample treatment methods of GB/T7293-2006 for determination of VE content in VE powder is not applicable the natural VE oil microcapsules prepared in this experimental, because Sample treatment methods of GB/T7293-2006 can not be fully to extract all VE oil in the natural VE microencapsule powder. A new Sample treatment methods which wall of microencapsule is broken with concentrated hydrochloric acid was build on the basis of GB/T7293-2006, and a new ways with ultraviolet spectrophotometer was used to determine the content of VE in VE microcapsules:3mol/L HCl was used to break the wall of VE microencapsule, natural VE concentrations in the range 19.46-97.3ug/mL, the absorbance and concentration showed a good linear relationship. Comparing the determination by by gas phase chromatography, the determination results of UV spectrophotometry can meet the requirements in accuracy, precision and reproducibility.Physical and chemical properties of natural VE microcapsules were researched. The moisture content and ash and angle of repose and surface oil content of VE in microcapsules after six after 6 months storage were were 1.94%,3.13%,41.7°, 4.68%. The effects of temperature, light under different storage conditions on quality of microcapsules,the result showed that microcapsules well preserved at low temperature and under dark. Environmental scanning electron microscopy showed the appearance of micro-capsules was good spherical and embedding was integrated and compact. FT-IR spectra indicated that the combination between wall material and core material relied on physical interaction. DSC indicated the glass transition temperature of the product is 35℃, which provides a reliable basis for storage of product at room temperature. After microencapsulation, the retention rate of natural VE increased significantly that indicated that the Composite wall material played a good protection on core material. The dispersion of microcapsule recovery emulsion was very goog, emulsion was uniform and stable and had narrow particle size distribution. pH values emulsion could maintained stablity for 6 hours in mineral acid and hydrochloric acid were 2.0 and 1.4 and toleranted the maximum concentrations of Fe2+, Ca2+, Mg2+were 0.008mol/L,0.032 mol/L,0.064 mol/ L. |
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