Abstract
This research was aimed to investigate the characterization of encapsulated vitamin A with a nanoemulsion system. First, the study was focused on a strong literature review on lipophilic vitamins encapsulation by oilin-water nanoemulsion. Mainly the ingridients used in emulsions and characterization of emulsions was studied in order to formulate and develop an emulsion system for encapsulation of vitamin A. Second aim was focused on preparation of vitamin A encapsulated in an oil-in-water emulsion by high pressure microfluidizer. Two variables (concentration of α-tocopherol and pressure of microfluidizer) were determined to study oxidative stability of vitamin A during storage test at 40°C for five weeks. The retention of vitamin A in presence of four different concentration of α-tocopherol (0, 0.25, 0.50, 1.00 mg/g) and four level of pressure (10, 20, 100, 200MPa) was mesured by HPLC-DAAD. The third aim of this study was to measure the physical stability of vitamin A encapsulated in oil-in-water nanoemulsion. Droplet size distribution and zeta potential as an indicator for droplet surface charge were measured and colloidal stability of prepared emulsions was monitored by turbiscan tower. The color changes of emulsions was also monitored as an indicator for emulsion chemical stability over accelerated storage test. Finally, in this research, the transient changes of Dulce de leche (A dairy product from Latin America) which is generally obtained after extensive heating of milk and sugar under mild alkaline conditions were monitored by direct injection mass spectrometer based on proton transfer reaction (PTR-MS). The rheology and texture properties of the Dulce de leche product were measured during the process.