|Ph.D Student||Uri Lesmes|
|Subject||Effects of Guest Molecules on the Structure and|
Functionality of Amylose-Based Nanocapsules
|Department||Department of Biotechnology and Food Engineering||Supervisor||Dr. Shimoni Eyal|
|Full Thesis text|
Unsaturated fatty acids in food are known to contribute to human health. However, their poor chemical stability is a major technological challenge when trying to supplement them to food. This study evaluated amylose and starches as possible hosts to form V-amylose molecular inclusion complexes with various fatty acids (FA’s). The hypothesis was that guest chemistry affects the supramolecular arrangement of the complexes, which in turn affects their colloid properties and susceptibility to enzymatic digestion. Furthermore, this study assessed a continuous dual feed homogenization process for the production of such complexes out of starches commonly used by the food industry.
First, this study focused on V-amylose complexes with stearic acid as a model system. The data collected by X-ray diffraction experiments, light scattering based particle sizing, NMR and atomic force microscopy (AFM) experiments shed some light as to the mechanism of the complexes’ formation, their structure and their colloid tendency to form what appears as aggregates of nanocapsules. Sequentially, complexes were produced with a series of unsaturated FA’s and data obtained reveals that FA unsaturation affects the structure and functionality of the complexes. 13C CP/MAS NMR spectra, light scattering based particle sizing and AFM images and analyses were used to ascertain that increased FA unsaturation lead to the formation of less defined crystallites with a rougher surface and bigger and more disperse particle populations. Differences were also found in the enzymatically induced release of the FA’s. Finally, a method was implemented in a dual feed homogenization process to produce V-type complexes from three commercial starches. It was found that the process enables rapid complexation coupled to particle size reduction. In some instances, V-type particles were found to be less than ~3μm in diameter and release the FA mainly upon pancreatic digestion.
Overall, this study demonstrates the effects of guest fatty acid chemistry on the long range order and functional properties of the resulting amylose based nanocapsules. Also, it describes and evaluates a technological platform for the production of V-type complexes from commercial starches. In the future, the insights described in this study might be used in tailoring and commercially producing such edible delivery vehicles for oral delivery of bioactives to the lower gastrointestinal tract.