The Study On The Preparation And Characteristics Of Microencapsulated Vitamin E

Some properties of vitamin E restrict its application in food industry. The microcapsules of vitamin E can maintain the inherent nature of vitamin E, overcome its some shortcomings such as easy to oxidize and do not dissolve in water, expand its application and improve its storage stability. In this paper, Microcapsules of vitamin E were prepared by two different methods, and the preparation processing, physical and chemical characteristics and the properties of storage of microencapsulated vitamin E were studied.Microcapsules of vitamin E were prepared by spray drying, using chitosan and maltodextrin as wall materials. When the mass ratio of lecithin to tween-80 was 4:2 in compound emulsifier, the microcapsule emulsion had the best emulsion stability. The optimal conditions of emulsion were: chitosan concentration 0.6%, maltodextrin concentration 20%, vitamin E concentration 6.5%, and emulsifier concentration 25%. During spray drying, the optimum conditions of inlet temperature and outlet temperature were respectively 190°C and 80°C.Vitamin E was microencapsulated in p-cyclodextrin with ultrasound-assisted and then embedded in secondary wall material, the study showed that the most suitable secondary wall material was whey protein concentrate (WPC). Response surface methodology (RSM) was employed to optimize encapsulation efficiency; based on single-factor experiments. The results of RSM showed that the optimum conditions were as follows: vitamin E-P-CD ratio 6:94, ultrasonic power 42%, the content of solids 15.5%, ultrasonic time 45min, and the content of WPC 3%. The experimental values agree with those predicted from the regression mode, indicating a good fitness. Results of DSC, FT-IR and X-ray diffraction showed that vitamin E has been embedded in p-CD and WPC, and inclusion complex did form between vitamin E and P-CD.The moisture content, repose angle and density of Microcapsules which were prepared by spray drying were 2.44%, 40.6°and 0.7227Kg/L, respectively. The moisture content, repose angle and density of Microcapsules that were prepared by using P-CD and WPC were 6.89%, 46.8°, 0.6372Kg/L, respectively.The results of scanning electron microscopy photographs showed that: the powders prepared by spray drying were relatively spherical, particle size and shape were uniform, and the inner structure was good. Whereas, the particle size and structure of microcapsules which were prepared by using P-CD and WPC were irregular.The results of differential scanning calorimetry (DSC) indicated that the vitamin E microcapsules prepared by two different ways had both good storage stability and which can be used widely.The study of TGA/SDTA revealed that: two microcapsules of vitamin E both could effectively improve the thermal degradation temperature of vitamin E, and both had high temperature stability. Thence, they could protect vitamin E from high temperature.In addition, the storage stability of microcapsules of vitamin E prepared by two means was investigated at 32%, 50% and 75% of different relative humidity. The results showed that the loss rate of Vitamin E at 75% of relative humidity was faster than other relative humidity, and at the same humidity, the loss rate of sample prepared by using spray drying was faster than another product. The loss data of the vitamin E was analyzed by Avramrs equation and the attenuation of vitamin E showed good fitness with Avrami's equation.