The Effect Of Blended Wall Materials On The Performance Of Microencapsulated Soybean Oil

Oil is an important classification of food. The storage stability, the environmentalresistance, the handling and transportation performance of oil can be proved bymicroencapsulation.In this thesis, soybean oil was used as the model core material. The forms of four typesblended wall material were determined through the primary selection of wall materials. Then,the mixture ratios of each blended wall material were established on the basis of preparationof a stable O/W emulsion. At last, comparisons with the performance of four types ofmicroencapsulated soybean oil were made, and the best blended wall material wasobtained.The main results were as follows:(1)Through the study of the ability of different wall materials to decrease oil-waterinterfacial tension and the properties of emulsions made by CAR-MD and CMC-MD, theforms of four blended wall materials were established as follows: AG-MD, OSA-MD,CAR-SPI-MD, CMC-SPI-MD.(2)The mixture ratios of each blended wall material were investigated by studying theemulsion properties, and the apparent viscosity, droplets size and distribution, stability ofemulsion were used as indexes Mixture ratios of four blended wall materials were as follows:AG(25%)-MD(75%), OSA(25%)-MD(75%), CAR(2%)-SPI(20%)-MD(78%),CMC(3%)-SPI(15%)-MD(82%).(3)The microencapsulation efficiency of four microcapsules was studied, which was animportant index to evaluate the quality of microcapsules.The results showed that the apparentviscosity and droplets size of emulsion and volatility of core material had effects onmicroencapsulation efficiency, and the microencapsuled soybean oil made by CAR-SPI-MDblended wall material had the highest microencapsulation efficiency (95.10%) among fourmicrocapsules.(4)A general comparison of four microcapsules was made according to particle size,surface morphology, thermal stability, glass transition temperature, storage stability andmoisture sorption of microcapsules. Among the four samples, the microencapsuled soybeanoil made by CAR-SPI-MD blended wall material was proved to be the best. Particle size ofmicrocapsule was17.59μm, and irreversible link bridges between particles were not observed.The microcapsule had good homogeneity with a Span value of1.51, and the highest thermalstability, glass transition temperature (48.89°C), and storage stability(the POV value ofmicroencapsulated soybean oil increased least, increasing0.80mmol/kg after stored at60°Cfor6weeks). The moisture sorption isotherm of microcapsule fitted GAB model well, and thevalue of M0was predicted, which was5.91g water/100g dry basis (aw=0.24), indicting thatthe microcapsule had the highest stability at this aw. The microcapsule had an intact structureeven though stored at aw0.765.