The influence of chemical interesterification on the physicochemical properties of complex fat systems. 3. Rheology and fractality of the crystal network

Colloidal networks of fat crystals

The following paper traces the development of the study of colloidal networks of fat crystals. The work starts with traditional pre-fractal particle network models of fat crystal networks. Due to its central importance in the study of colloidal networks of fat crystals (and other colloidal aggregates), a short exposition of fractal geometry is provided. The development of fractal aggregation models as well as models that describe the rheology of networks of these fractal aggregates is introduced. Later sections of the paper show the application of these aggregation and mechanical models specifically to fats. Finally, recent work in elucidating the nanostructural elements of fat crystal networks and aggregates of these nanostructures is provided.

Development of Novel Shortenings Structured by Ethylcellulose Oleogels

A novel shortening was developed based on oleogels structured by ethylcellulose (EC) polymers. The texture and oil retention ability of EC oleogels were characterized against the level of viscosity of different grades of EC, as well as the rheological properties in relation to the polymer structure in the gel network. EC100, which has an average viscosity of 100 cP, was selected as the most suitable organogelator at 4% (w/w) in combination with base oil (30% degree of saturation by mixing palm stearin and soybean oil) to form the shortening. Triglyceryl monostearate (TMS) was found to be the most effective emulsifier as evidenced by its ability to strengthen air-incorporation ability of the shortening while creating evenly distributed fine crystals in the system. The EC100 shortening was able to create breads with excellent specific volume, indicating its ability to incorporate air bubbles during dough development and to serve as an antifirming agent to create bread with stable soft texture. PRACTICAL APPLICATION: In the present study, we attempted to create a novel shortening by employing oleogels structured by ethylcellulose (EC), the most promising gelation agent to develop gel network capable of replacing solid fat without health concerns. EC oleogels in shortening with detailed characterization of the shortening microstructure in relation to its functional properties was elucidated. The optimal formulation in relation to preservation of gel structure and consistency with enhanced moisture and air retention were also identified.

Quantitative study on the microstructure of colloidal fat crystal networks and fractal dimensions

This paper highlights the most recent progress in the quantitative study on the microstructure and the rheological properties of colloidal fat crystal networks. Several physical models describing the structural hierarchy of the colloidal fat crystal networks are reviewed here, with particular emphasis on fractal model, which can be used to explain the scaling behavior of fat crystal networks. The concept of the fractal dimension has been extensively used in the quantitative study of the microstructure of fat crystal networks and other colloidal networks; however, the relationship between the fractal dimension value and microstructural characteristics remains somewhat nebulous. Recent computer simulation work from our laboratory will be presented relating simulated microstructural features to values of particular measure of fractality including the box-counting, particle counting and Fourier-transform fractal dimensions.