Preparation, Characterization And Application Of DHA-loaded Solid Lipid Nanoparticles (SLN)

DHA has a variety of functions, but it is very easy to oxidize, so it is difficult to add it intofood. This experiment of research will attempt to solve the problem, making food which is addedDHA to have the better stability and longer shelf life, meeting people’s need. The purpose of thisresearch is to compare two methods of preparation DHA solid lipid nanoparticles, to find theadvantage and mode of two methods.Glyceryl monostearate was used as rampart materials to embedding DHA in algae oil, studiedinfluencing factor of preparing DHA solid lipid nanoparticles by single factors trials and responsesurface trials, embedding rate as indicators to decide the best preparation process parameters;analyzed characteristics of DHA solid lipid nanoparticles gained the best preparation of DHA solidlipid nanoparticles and applied DHA solid lipid nanoparticles into milk.The main results are following:1. Studied the best preparation process parameters of DHA solid lipid nanoparticles by twopreparations which are high pressure homogenization and molten ultrasonic. The best preparationprocess parameters of DHA solid lipid nanoparticles by high pressure homogenization: corematerial ratio was1:65, homogeneous pressure was80MPa, the mass percentage of emulsifier was2.14%, the number of homogeneous was8, the embedding rate was75.41%; The best preparationprocess parameters of DHA solid lipid nanoparticles by molten ultrasonic: the core wall ratio was1:63, homogeneous pressure was113.8MPa, the mass percentage of emulsifier was2.10%, thetime of ultrasonic was3.5minute, the embedding rate was74.63%.2. Comparing the characteristics of DHA solid lipid nanoparticles, which were prepared byhigh pressure homogenization and molten ultrasonic, by analyzing grain diameter, Zeta potentials,microscopic observation, DSC curves and released in a simulated gastrointestinal fluid. Theaverage values of grain diameter were164.5±18.7nm and126.4±15.3nm, both of them were inthe nano-level, polydispersity were1.12and1.98and the stability was well. The absolute value ofZeta potentials were between30~60mV, both of them are stable system. Observed the microscopicby transmission electron microscope, DHA solid lipid nanoparticles was independent grain, someof them were easy to recognize, and the appearances were globular. The DSC curves reflect thatthe phase-transition temperature of DHA solid lipid nanoparticles were stable, no else peaks, every matter combined together, the solid lipid nanoparticles were stable. In a simulated gastrointestinalfluid, with the passage of time, the content of free fatty acid was increased, showed that DHA solidlipid nanoparticles released and degradation, but the speed of degradation in intestinal was faster.The DHA solid lipid nanoparticles we prepared have a better stability in infant liquid formulationsof imitation milk.3. Preparation of DHA solid lipid nanoparticles applied in liquid infant formula of genericmilk has good stability and sensory properties. DHA solid lipid nanoparticles particles in liquidinfant formula of generic milk, at4℃refrigerator, within a week baby liquid formula of genericmilk smell, colour and lustre and sensory properties such as no bad organization status changes.The stability of DHA solid lipid nanoparticle is good. After7days the DHA content is determined,keep the original content of95%. Other properties of the liquid milk to infants had little impact.This research found that, the embedding rate of DHA solid lipid nanoparticles prepared byhigh pressure homogenization was higher than the DHA solid lipid nanoparticles prepared bymolten ultrasonic, but the grain diameter of DHA solid lipid nanoparticles prepared by moltenultrasonic was shorter and evenly distributed, the stability was also better. The ultrasound inpreparation process was easy to cause the remaining of small metal fragment. Compare with themolten ultrasonic, the high pressure homogenization can work continuously and the characters ofproduct are stable, although the grain diameter was a little bigger, it fits large-scale production.The molten ultrasonic is fitter for preparation of laboratory tests.The embedded DHA was far more stable. We can add it into dairy and other foods. Thecontent of DHA is high and EPA is low decreased because it was embedded in algae oil. So it isfit to add in to infant food.