|M.Sc Student||Gilad Markman|
|Subject||Maillard-Reaction-Based Compounds as Nanovehicle for|
Enrichment of Clear Beverages with Hydrophobic
|Department||Department of Biotechnology and Food Engineering||Supervisor||Professor Livney Yoav|
|Full Thesis text|
Protein-Polysaccharide conjugates covalently bonded by Maillard reaction have been shown to be emulsifiers with better surface activity and emulsion stabilization capacity than the proteins used to form them. Such conjugates have been proposed as encapsulation agents, but their potential as nanoencapsulation agents in clear beverages has not yet been proposed or explored. When conjugating a protein and a polysaccharide by the Maillard reaction, a block copolymer is formed by Schiff-base formation between the saccharide reducing end and an amine residue of the protein. In this research we formed casein-Maltodextrin (CN-MD) conjugates and co-assembled them with hydrophobic nutraceuticals to create nanovehicles for enrichment of clear aqueous beverages. Conjugation was validated using gel electrophoresis and by ortho-phthaldialdehyde (OPA) assay. Vitamin D was nano-entrapped by the conjugates, and compared to controls based on unconjugated CN-MD mixture, and unencapsulated vitamin. The following advantages of the conjugates were shown: the diameter of conjugate- vitamin D nanoparticles was smaller and their solution was more transparent than that of the protein-polysaccharide mixture with vitamin D. Conjugates conferred better protection against oxidation to both Vitamin D and Epigallocatechin gallate (EGCG) than the mixture did. Conjugates were more colloidally stable at the CN original pI, allowing the formation of nano particles with mean diameter below 30nm when mixed with Vitamin D, even at the original pI of CN. Conjugates provided protection against degradation by heat, low pH and during shelf life. Entrapment efficiency was measured using Nile Red (NR), a fluorescent model for a hydrophobic nutraceutical. Protein affinity to the hydrophobic compound was not diminished due to conjugation, and 90% entrapment efficiency was obtained at the conditions tested. During simulated gastric digestion, Nile red was not released from the conjugates, suggesting potential application in enteric delivery.