Microbial encapsulation and interactions in emulsions

El Kadri, Hani (2018). Microbial encapsulation and interactions in emulsions. University of Birmingham. Ph.D.

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Previous studies indicated that emulsions with nano-sized droplets or nano-emulsions possess anti-microbial activity. The microstructure of water-in-oil-in-water (W1/O/W2) emulsions present interest for microbial encapsulation in food, cosmetic and pharmaceutical applications. Therefore microbe-emulsion interactions need to be characterised in order to fully explore the potential of such applications. This thesis investigated the effect of nano-emulsions on bacteria as well as W1/O/W2 emulsion feasibility for encapsulation and triggered release (altering osmotic pressure) of bacteria and in real life application by incorporating in set-style yogurt model system for protection of probiotics were investigated.
Exposure of bacterial cells to nano-emulsions was found to have no significant effect on the survival or growth bacteria and cell membrane integrity was not compromised. Bacteria had no effect on the stability of nano- and double emulsions. The release of bacteria form W1/O/W2 emulsion occurred due to the bursting of the oil globules independent of diffusion mechanisms and be controlled by altering the structure of W1/O/W2 emulsion. W1/O/W2 emulsion had a significant effect on texture and physicochemical properties of yogurt but no effect on bacterial growth kinetics while probiotics maintained high viability at the end of the fermentation.
In summary, this thesis demonstrates the feasibility and applicability of W1/O/W2 emulsion for the encapsulation of microbial cells for the purpose of their protection and triggered release. The results of this thesis can be used in the formulation of better probiotic products, segregation, protection, and release of microbial cells during fermentation as well as for in vivo delivery of fermentation.

Type of Work: Thesis (Doctorates > Ph.D.)
Award Type: Doctorates > Ph.D.
College/Faculty: Colleges (2008 onwards) > College of Engineering & Physical Sciences
School or Department: School of Chemical Engineering
Funders: None/not applicable
Subjects: T Technology > TP Chemical technology
URI: http://etheses.bham.ac.uk/id/eprint/8192


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