|M.Sc Student||Radetsky Irina|
|Subject||Combined Encapsulation for Enhanced Bioavailability of|
|Department||Department of Biotechnology and Food Engineering||Supervisor||Dr. Eyal Shimoni|
|Full Thesis text|
The role of dietary active compounds in human nutrition is very important. One of these compounds is Curcumin; however, when applied orally, Curcumin exhibits low bioavailability. The goal of this study was to create Curcumin microcapsules, which increase its stability in food and deliver it through the upper GI tract.
The envisaged technology is expected to protect Curcumin and other functional ingredients through microencapsulation, creating a multilayer coating and a multicompartmental system where core ingredients are separated and released by a time control mechanism, first releasing the bioavailability enhancers and then functional ingredient. Bioavailability enhancers such as Piperine, Quercetin and Genistein are known to increase the bioavailability of Curcumin.
First, we focused on developing a microencapsulation process for Curcumin and enhancers. Fluid bed microencapsulation was used for the coating, while optimizing the process parameters, such as spray rate, solid concentration of the coating solutions, fluidization level of particles and drying temperature. To provide optimal formulation of coated Curcumin, different combinations of ethylcellulose (Ethocel), types 10 and 100 were used as enteric coating and hydrogenated vegetable oil (HVO) was used as a potential protector against migration of moisture from the environment into the capsules.
Size analysis and particular size distribution were performed by light scattering and sieve test. Scanning Electron Microscope (SEM) was used to characterize the capsules. Thermal properties of the coating materials were examined by Differential Scanning Calorimetry (DSC), which revealed no interaction between them. Integrity of Curcumin microcapsules during thermal treatments was evaluated. Storage conditions, such as temperature, humidity and formulation influence on Curcumin’s shelf life were examined. HVO coating increased storage stability in humid environments (aw = 0.55). Ethocel-HVO bi-layer coating provided good protection in simulated GI conditions. Optimal formulation was selected after the characterization of the samples and the release of Curcumin in simulated GI conditions at time intervals was evaluated. The sample was incorporated into dry pasta and bread, and properties were examined. Bioavailability test in human volunteers was performed. Incorporation of the encapsulated sample into dry pasta improved sensory acceptability, unlike nonencapsulated Curcumin. In vivo test showed that microencapsulation followed by enteric coating increased the bioavailability of Curcumin compared to the free ingredient, though microencapsulated samples with added enhancers provided no additional improvement.
In the future, the model developed in this study, a targeted release vehicle, can be applied in commercial production, to overcome the absorption limitations of sensitive functional ingredients.