טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentDavid Shlomit
SubjectPotato Protein-Based Nanovehicles for Health-Promoting
Hydrophobic Bioactives in Clear Beverages
DepartmentDepartment of Nanoscience and Nanotechnology
Supervisor Professor Yoav Livney
Full Thesis textFull thesis text - English Version


Abstract

Vitamin D is a fat soluble nutraceutical of great importance for multi-system function: calcium and bone metabolism, insulin reactivity, cell differentiation, the immune system and more. It was found that maintaining proper levels of vitamin D helps preventing a host of illnesses. Although humans can synthesize vitamin D in the skin upon sun exposure (ultraviolet type-B radiation) vitamin D deficiency is very widespread. Its food sources are scarce, and thus, there is a high need for fortification of staple food and popular beverages with this vital micronutrient. Fortifying beverages with vitamin D poses tough challenges especially due to its low aqueous solubility. Moreover, vitamin D is sensitive to light, oxygen and high temperature and is adversely affected by acids. Most food grade surfactants, which may be used for the task are synthetic, and thus preclude an “all-natural ingredients” labeling. Other ways to enrich beverages with hydrophobic nutraceuticals are either expensive, not always available, or are using allergenic components.


We have demonstrated the possibility of using potato proteins as protective nanovehicle for delivery of vitamin D in clear beverage solutions. Potato proteins are produced from a widely available and cheap raw material, they are considered GRAS and non-allergenic, they are natural and applicable in vegetarian, vegan and KOSHER PARVE products.


In the current study we aimed at characterizing the complexes in terms of size and turbidity, and quantifying the extent to which potato proteins protect vitamin D during thermal treatment and shelf life.


The addition of Vitamin D to aqueous solution causes turbidity. However, when Vitamin D was added to potato protein solution (at acidic pH of 2.5) nanocomplexes were formed and the solutions obtained were transparent. This was confirmed by UV absorbance spectroscopy. Dynamic light scattering showed that vitamin D - potato protein co-assemblies were much smaller than the vitamin D aggregates without potato protein: two subpopulations in terms of size were observed with an average diameter in the range of ~30-100 nm vs. above 500 nm for uncomplexed VD. The nanocomplexation provided protection and reduced vitamin D losses during pasteurization and during simulated shelf life tests under several different sets of storage conditions: at room temperature, with and without exposure to light, the half life of the VD was increased by 14 and 17 days, respectively, when complexed with potato protein. At 4°C the VD in the complexes solution was not degraded at all within the 3 weeks observation time. The protection conferred to VD by the potato protein was compared to that of Tween 80 emulsion. In the shelf life tests at room temperature when exposed to light and at 4°C there was no significant difference between the Tween 80 and potato protein. The protection conferred by the potato protein during thermal treatment was improved by the removal of iron ions.

Hence potato protein shows promise as a good protective carrier for VD, and possibly other hydrophobic bioactives, for enrichment of clear beverages (particularly acid ones) and other food & drink products, to promote human health.