Xanthan encapsulation

In addition to the necessary protection of the contents of the emulsion droplets, effective encapsulation technology requires that the release of the active matter be controlled at a specified rate. Benichou et aL (2004) have demonstrated that a mixture of whey protein isolate (WPI) and xanthan gum can be successfully used for the controlled release of vitamin Bi entrapped within the inner aqueous phase of a multiple emulsion. The release profile, as a function of the pH of the external aqueous phase, is plotted in Figure 7.25. We can observe that the external interface appears more effectively sealed against release of the entrapped vitamin at pH = 2 than at pH = 4 or 7. It was reported that an increase in the protein-to-potysaccharide ratio reduced the release rate at pH = 3.5 (Benichou et aL, 2004). More broadly, the authors suggest that compatible blends of biopolymers (hydrocolloids and proteins) should be considered excellent amphiphilic candidates to serve as release controllers and stability7 enhancers in future formulations of double emulsions. So perhaps mixed compatible biopolymers wall at last allow researchers to... 

Gellan or xanthan gums are polysaccharides of microbial origin, obtained from Pseudomonas elodea and Xanthomonas campestris, respectively. Their mixture was reported to be extremely suitable to encapsulate probiotics in systems with high resistance in acidic environments. ... 

Giannouli P, Morris ER (2003) Cryogelation of xanthan. Food HydrocoUoids 17 495 Griffin DR, Kasko AM (2012) Photodegradable macromers and hydrogels for live cell encapsulation and release. J Am Chem Soc 134 13103... 

PE complexes made out of chitosan and xanthan were found to exhibit pH dependent complex formation. At pH 1.5, only 21 % of the PE form complexes, while this increases to 98 % at pH 6.3 [184]. The fibril structures of the complex exhibited sizes from 50 to 100 nm, with pore sizes ranging from 100 nm to 1 pm, making the formed gel like structure suitable for drug and enzyme encapsulation [184]. The enzymes showed a very different behavior—some exhibited an increase in activity, while others a decreased activity in the encapsulated state [184]. This behavior is probably caused by a reaction to steric hindrance as well as a change in the water structure, and dielectric and ionic fields in such a complex network compared to solution. 

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