| Nutritional oils for infant formula was microencapspsulated by spray drying method with coating materials including vegetable protein and carbohydrate. Using the appropriate encapsulating substances, the functional fatty acids in microcapsules can be protected from oxidation and deterioration caused by production process and adverse environmental conditions after open package. In this way, it ensure the nutritional quality and edible safety of infant formula. This paper discusses the effects of different technology and formula on MEE and MEY by using single factor experiment and the response surface methodology (RSM). Its provides an important theoretical basis for subsequent study under the optimized formula. The determination results of fatty acids in vegetable oil by gas chromatography show that the composition as close as possible to that of human milk fat (HMF) , it could be used for infant fomular to make up some deficiencies of milk powder in nutrition and functional properties. Results of this study were as follow:1. This paper utilized a linear restraint function in Matlab optimization toolbox and programming in MATLAB. It solves the vegetable oils formula at a reasonable fatty acids ratio and the lowest price and uses Matlab language to compile program on the basis of establishing mathematical model. This method to obtain the vegetable oils formula of ten groups (coconut oil, palm oil, sunflower oil, soybean oil, perilla seed oil).The determination results of fatty acids in vegetable oil by gas chromatography show that the fatty acids composition of formula is according with the standard of infant formula and the composition as close as possible to that of HMF, especially formula 10 . The optimized formula is 13.6%coconut oil, 50%palm oil, 14%sunflower oil, 21%soybean oil, 1.4% perilla seed oil, the optimized price is 9.53 yuan/kg.2. Nutritional oils for infant formula was microencapsulated by spray drying method with coating materials including maltodextrin(MD), soy protein isolate(SPI) and emulsifier (soy lecithin). Vegetable oil blend was prepared by mixing coconut oil, palm oil, sunflower oil, soybean oil, perilla seed oil at a ratio to achieve a fatty acid profile comparable to HMF. The effect of oil concentration, SPI concentration, solids concentration and soy lecithin on MEE and MEY were studied in detail by using single factor experiment.This paper use central composite design (CCD) for the optimization of nutritional oils microencapsule, the results show that the optimal formula of nutritional oils microencapsule is nutritional oils 27.28%, solids concentration 39.74%, SPI concentration 40.00%, soy lecithin 1.47%。With this understanding, the MEE and MEY can resch 91.188% and 96.1129% under optimal condition. The expectation of nutritional oils microencapsule is 0.894.3. The surface structures of microencapsulation at the optimized condition (95.23% in MEE) and the control group (70.21% in MEE) were verified by using a scanning electron microscopy (SEM). The microparticles (95.23% in MEE) had generally spherical shape and smooth surface, without depression, aperture and crack. However, the microparticles of the control group (70.21% in MEE) had many hollow and crack. The particle diameter of microparticles were measured by SEM. The mathematical mean of microparticles is 24.2769μm.The result of Schhal oven method show that the flavor and odor of nutritional oils microencapsule hardly any change during the testing period. The POV of nutritional oils microencapsule is lower than 12meq/kg, The POV of nutritional oils is more than the national standard. According to the empirical formula of Arrhenius, The results show that the shelf life of nutritional oils microencapsule could be as long as 24 months.The glass transition temperature (Tg) value of spray-dried nutritional oils measured by DSC were 65.18℃. The Tg value of microencapsulated nutritional oils was far higher than usual storage temperature, so it indicated that microencapsulated nutritional oils would be very stably storied at room temperature. The oranoleptic indicator, physicochemical Index and hygienic standard of nutritional oils microencapsule are accord with national standard after evaluation.4. Microencapsulated nutritional oils for infant formula. Briefly, microencapsulated nutritional oils was prepared by mixing with other food material. The mixture was stirred vigorously by mixer to ensure uniform distribution, package charged with nitrogen after stirring. The nutritional ingredient and hygienic standard of nutritional oils microencapsule are accord with national standard.
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