Density and Microviscosity Studies of Palm Oil/Water Emulsions

Abstract

Electron paramagnetic resonance (EPR) and densitometry were used to measure the temperature- and rate-dependent formation of fat crystals in emulsion droplets in hardened palm kernel oil in water emulsions. The solid fat content in emulsions can be critical for the functionality of the emulsions in a wide variety of applications. Therefore, new and accessible methods are needed to monitor solid fat content in order to control the functional properties of these emulsions. EPR measurements showed that the microviscosity within the oil droplets could be measured as a function of temperature and that the storage temperature below the main fat melting point is crucial for an increase in the microviscosity, due to fat solidification. The microviscosity of the oil droplets could be an important parameter for defining functional performance (e.g., rheology and partial coalescence). Density measurements provided a simple and accurate method for monitoring changes in phase state of the oil. The phase behavior agreed well with the EPR results, demonstrating that accurate density measurements could prove to be a valuable tool for monitoring fat crystallization processes.

In situ measurements of dispersed and continuous phase viscosities of emulsions using nanoparticles

“…The viscous properties of the continuous and dispersed phases in emulsions are expected to contribute to the overall emulsion rheology [1][2][3][4][5], but have not been independently investigated in situ to any appreciable extent due to lack of suitable methods. Rheological properties of emulsions are commonly characterized in the bulk using conventional macro-scale instruments such as controlled-shear or controlledstress rheometers [4,5].…”

ESR/Spin Probe Study of Ice Cream

“…Combined with the selection of an appropriate spin probe, ESR can be invaluable for studying materials containing fat and water ( , ). We have found that spin probes based on the 1,1,3,3-tetramethylisoindolin-2-yl structure (TMIO) are superior to commercially available spin probes such as TEMPO (): The main reasons are that there are fewer unresolved proton interactions and the molecules are rigid so that rapid interconversion does not increase the line width.…”