PFG-Untersuchungen an Monoglycerid-Gelen und Wasser-Öl-Emulsionen
Both series of monoglyceride gels samples with different monoglyceride concentration of two monoglycerides C14 and C16/18 and series of water-in-oil emulsions that differ from flocculation, water concentration and biopolymer have been investigated by means of PFG NMR. Aim of the measurements was to determine microstructural parameters characterising such heterogenous systems. For the monoglyceride gels a return-to-the-origin probability, the average surface-to-volume ratio of the pore space as well as the tortuosity and dimensionality of the network could be calculated on the basis of echo attenuation and diffusion curves. Additionally pore size distributions have been determined for the monoglyceride gels. The results verify a postulated crystallisation process for monoglyceride gels and were validated by CryoSEM images and image analysis. The PFG NMR findings of the water-in-oil emulsions have been fitted with four various models which were developed in the context of this thesis and assume different diffusion behaviour of the water molecules. All models show individual deficits as the real movement of water molecules in the water-in-oil emulsions is more complex than assumed. Non flocculated and flocculated emulsions could be characterised and the droplet and aggregate size as well as the effective diffusion coefficient could be calculated. The results have been corroborated by CSLM images and image analysis.