Preparation, Characterization And Application Of Safflower Oil Microencapsulation

Safflower oil is a health-care edible oil, which is rich in nutrients, containing more than73~85%linoleic acid. However, linoleic acid is an unsaturated fatty acid which is unstableand easily oxidized. As the result, the nutrition and physiologically active function ofsafflower oil can not be unutilized efficiently, and the application for food industry has beenlargely restricted. In this research, the microencapsulation of safflower oil was studied byspray drying, using isolated soy protein (SPI), β-cyclodextrin (β-CD) and soluble starch ascapsule materials in order to avoid the oxidation of safflower oil.Firstly, six safflower oil microcapsules preparation programs were selected and thequality of microcapsules were evaluated by determining encapsulation efficiency, as well ascomparing the advantages and disadvantages of the products. The safflower oilmicrocapsule production formula was determined: wall materials are soybean protein isolate,β-cyclodextrin, soluble starch, and mass ratio is1:1:1; the amount of core material saffloweroil is40%, with the addition of2%emulsifier (mass ratio of monoglycerides to sucroseesters is1:1); solid content is15%. The materials were emulsified and homogenized. Theoptimal technological parameter of spray drying is inlet air temperature180℃.Microencapsulated oil content was35.83%, the surface oil content was5.45%and themicroencapsulation efficiency was84.49%.Physical and chemical characteristics of the microcapsule were investigated (includingmoisture content, ash content, protein content, the bulk density of the microcapsules, themoisture resistance of the microcapsules, particle size, the structure constitution of samples,thermodynamic stability and microscopic structure) and then storage stability of theproducts were researched. The results showed that the safflower oil microcapsule had awater content of3.36%, ash content of1.46%, protein content of20.56%, the bulkdensity is0.3151g/cm3，the angle of repose is32.4°, the range of particle size is in1~10μm. The microencapsulated safflower oil had also showed good oxidation stability andstorage stability.Further study on the release properties of the microcapsule product was conducted andthe retention ratio of microencapsulated safflower oil was measured at different relativehumidity and different storage temperatures. The Avrami’s equation was used to provide kinetic parameters such as release mechanism parameter and release rate constant. Resultsshowed that: with the process of storage, the release rate was raised with the increasing ofthe storage temperature and humidity.The effects of safflower oil microcapsules on rheological properties of wheat flourdough were studied using farinograph and extensograph as the analytical tools. The resultshowed that the addition of safflower oil microcapsules to wheat dough could obviouslyimprove the quality of wheat flour dough, including stability, water absorption, extensibility,the development time, farinograph quality number, extensible area and maximum extensionratio. The quality of steamed bread with the addition of six different amounts of themicrocapsule oils was studied and then the sensory evaluation of steamed bread was alsoconducted.