Engineering and Architecture
Montserrat Ferrando Cogollos
Nanoscience, Materials and Chemical Engineering
New strategies to encapsulate probiotics in dispersion-based systems
Probiotics, mainly acid lactic bacteria (ALB), are beneficial for human health. Their successful incorporation into foods encompasses the need of a minimum concentration and mild process conditions. Encapsulation in multiple emulsions has been described as a suitable methodology to protect ALB and meet the requirements for being incorporated into foods. The use of microstructured systems for emulsification ensures the use of mild conditions compatible with the encapsulation of ALB. Scale up for industrial production of this type of encapsulates can be done using microporous systems such as packed beds of silica beads that are low energy intensive, compatible with food grade materials and easy to clean. Previous research on the production of multiple emulsions is available, but further knowledge for more complex interfacial systems is required to model the mechanisms of ALB release. Alternatively, microfluidic emulsification offers the fabrication of multiple emulsions with complex drop morphologies. One of the most attractive features of microfluidic techniques is that an emulsion is made by precisely fabricating one drop at a time, enabling to directly monitor the emulsification process and, in turn, the impact of emulsion formulation on droplet formation and stability.
The objectives of the thesis are: i) to design dispersion-based systems obtained by microfluidic emulsification, to optimize viability and encapsulation efficiency of ALB and ii) to scale up the production of dispersion-based systems using microporous emulsification while considering the properties determined by microfluidic emulsification.
The microfluidic emulsification system will be used to design multiple emulsions with the ALB encapsulated in the inner water phase. Droplet size, phase fractions and composition are the key parameters for ALB viability and hence for a successful encapsulation. Based on the co-flow emulsification results, microporous emulsification with packed beds will be tuned to produce multiple emulsions showing the best performance in terms of stability, encapsulation efficiency and ALB viability. Moreover, microfluidic devices will enable to link interfacial composition and emulsion stability, and to study mechanisms of ALB release.
The advantages of encapsulating microorganisms in multiple emulsions are the protective effect of the oil/water layers and the release under trigger conditions. Co-flow emulsification will determine how parameters such as droplet size, phase fractions and interfacial composition affect viability and encapsulation efficiency of ALB. Microporous emulsification has arisen as a suitable technology to produce multiple emulsions, which can be applied to encapsulate ALB. Results of co-flow and microporous emulsification will assist the process scale-up.
37.5 hours a week
|This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 713679|