Formulation And Characterzation Of Food Functional Factors/Surfactants Self-Assemble Systems

Epidemiologic and experimental data have provided evidence for a beneficial effect of water insoluble functional food factors. However, these factors are water-insoluble, especially sensitive to light, temperature and easily to be oxidized. Self-assemblies of surfactants (such as microemulsion, liquid crystal and vesicle) possess several advantages over their solvent-based counterparts, which are thermodynamically stable, nanoscale droplets, easy to prepare and low cost. In this paper,α-Linolenic Acid (ALA), conjugated linoleic acid (CLA), and curcumin microemulsions were prepared. The particle diameter, polydispersity index, encapsulation position, stability and rheological properties of these systems have been observed by dynamic light scattering (DLS), TEM, 1H NMR spectroscopy and rheological techniques. And the microstructures and dynamic rheological properties of lyotropic liquid crystal phases have been studied with the aid of small angle X-ray scattering (SAXS) and rheological techniques for the systems of ALA, CLA with nonionic surfactants and water. In details, the results of the researches as following:(1) The most attractive researches in the field of functional food factor carriers, such as cyclodextrin, lipidosome, inorganic nanophase materials and self-assemblies of surfactants, have been summarized. Furthermore, progress in food delivery system study of surfactant aggregates has been intensively analyzed. Spontaneous vesicle systems which were used as all-trans retinoic acid (ATRA) delivery systems were prepared. These nanophase delivery systems will be of great importance in food appearance, quality, and efficacy.(2) A novel ALA-in-water microemulsion composed of ALA as the continuous oil phase, water as the dispersed phase, and a mixture of EL-35 / Span80 as the emulsifiers were prepared and investigated as potential food delivery systems. The influences of pH on the microemulsion region were considered. The microstructure and characterization of microemulsion were determined by dynamic light scattering, negative-staining TEM and rheological behavior. The location of ALA molecules in the microemulsion formulations was determined by 1H NMR spectroscopy. The results show that the size of O/W microemulsion droplets depends strongly on the contents of ALA, and the diameter ranges from 22.1 to 42.1 nm. All samples keep a remarkable stability in the experiments of 60 days. The results of DLS and 1H NMR confirmed that the ALA molecules are solubilized in oil core of the O/W microemulsions drops in low ALA concentration. With the addition of ALA, they are solubilized in the hydrophilic shells of the microemulsion. The rheological results showed that the flow behaviour of microemulsion follows shear thinning. All microemulsion samples exhibit two Newtonian regions, and in low shear-rate region, the flow behavior can be described by the Carreau model. Centrifugation and storage experiments were used to test the stability of beverage samples with microemulsion system. The results showed that ALA could be added into juice, coke and sports beverage under a certain conditions.(3) CLA-in-water microemulsion based on Tween80, EL-35, ethanol and n-octanol was investigated as potential food delivery systems. The size of O/W microemulsion droplets depends strongly on the contents of surfactants and CLA, and the diameter ranges from 22.1 to 30.7 nm and from 18.3 to 32.8 nm respectively. All samples keep a remarkable stability in the experiments of 30 days. The stability of CLA in microemulsion and ethanol solution was determined by UV-vis spectrophotometry, the results revealed that the stability of the CLA in the microemulsion was increased remarkably. The stability of multiple emulsions showed that the optimum conditions for solo emulsifier system are: M (Span80)∶M (Tween80) =9.0, the mass fraction of the emulsifier in the emulsion is 9.7%, the oil to water mass ratio is 5.0 in first phase, and the mass ratio of first phase to second phase is 6.0∶1.3. The optimum conditions for complex emulsifiers system are: HLB of the emulsifier in the first phase is 7.4, M (mult-emulsifiers)∶M (Tween80)=9.0, and the mass fraction in the emulsion is 6.7%.(4) The ternary phase diagram of a curcumin-encapsulated O/W microemulsion system using food-acceptable components, Tween 80 as the surfactants, ethanol as the cosurfactant and isoamyl acetate as the oil phase was constructed. The stability and characterisation of curcumin in microemulsion were investigated. The results indicated that the diameter of microemlsions increased with the addition of curcumin. 1H NMR confirmed that the curcumin molecules are solubilized in palisade layer of the O/W microemulsions drops. microemulsion can significantly increase the solubility of curcumin in water. A permeation study for testing the penetration effect of various curcumin loading in the microemulsions in different dialysates was also performed and discussed.(5) The bicontinuous cubic (Ia3d) and lamellar liquid crystals were approved in EL-35/ALA/H2O system. The results of SAXS show that the lattice parameter and water channels radius (r) of cubic phase and the repeated distance (d) of lamellar phase get increased with the increase of water contents, and the area per surfactant at the hydrophobic/hydrophilic interface (aS) has no significant change. ALA is solubilized in the core of the micelle. The storage moduli are bigger than loss moduli for all samples. A certain concentration participation of ALA will stabilize the structure of liquid crystal. The cubic and lamellar phases were discharged into O/W microemulsion at 49 and 43°C, respectively.(6) The phase diagram of EL-35/AEO2/CLA/H2O system was prepared. The microstructure and rheological properties were researched by SAXS and rheological technique. The results of SAXS show that the repeated distance (d) and the area per surfactant at the hydrophobic/hydrophilic interface (aS) of lamellar phase get increased with the increase of water contents. CLA is solubilized in the core of the micelle. The dynamic rheology results show that the strength of lamellar phase network and the phase transition temperature are increasing with the increase of water contents. The different in the EO units among the AEO surfactants has an obvious effect on the lamellar phase. The interface layer arranged is looser, the strength of phase network and the crossover frequency decreases with the increase of EO units.