Double emulsions stabilized by new molecular recognition hybrids of natural polymers.

Citation:

Axel Benichou, Aserin, Abraham , and Garti, Nissim. . 2002. “Double Emulsions Stabilized By New Molecular Recognition Hybrids Of Natural Polymers.”. Polymers For Advanced Technologies, 13, 10-12, Pp. 1019–1031. doi:10.1002/pat.270.

Abstract:

Water-in-oil-in-water (W/O/W) double emulsions with improved stability and less polydispersity in droplet size distribution were prepd. using polyglycerol polyricinoleate (PGPR) as emulsifier in the inner aq. phase and replacing the common nonionic hydrophilic monomeric emulsifiers by a "protein-polysaccharide hybrid" in the outer interface. Amphiphilic macromol. hybrids with specific interfacial recognition capabilities to be termed "biomacro-mol.-recognition hybrids" have been prepd. in aq. soln. by interacting whey protein isolate (WPI) with hydrocolloids (xanthan gum, galactomannans) at selected pH and wt. ratios. The binary aq. mixts. do not coacervate or ppt. but form stable mol. adducts. At pH lower than the isoelec. point of the protein (pH 4.6), the yield of encapsulation of glucose (a model marker) in the inner phase of the double emulsion is close to 95%. The emulsion droplets are stabilized by both steric and electrostatic contributions (zeta potential is close to +30 mV). Rheol. measurements indicate that, at low pH, such systems behave as viscous ones with G'' (loss modulus) greater than G' (storage modulus). When the pH is close or greater than the isoelec. point of the protein, the system exhibits a more pronounced elastic behavior (G' \textless G'') that can explain the redn. in emulsification capabilities of such mixts. In this case the yield of encapsulation is less than 10% and the double emulsion droplets are larger than 10 $μ$m. At pH ≤ 2, the adducts can efficiently stabilize double emulsions and serve as an efficient and thick barrier against the release of vitamin B1 entrapped in the core of the W/O/W double emulsions. The release of the vitamin was less than 18% after three weeks of storage at room temp. (against 100% of release at neutral pH). [on SciFinder(R)]

Last updated on 05/27/2020