Research Projects

ABSTRACT

In the field of material science, a number of properties have been shown to provide the basis for linking of biopolymers and related molecules as natural building blocks to provide either hollow, or porous and non-porous structures with varying degrees of internal and external organization thus indicating a part of their encapsulating potential. In particular, polymers, such as structural components of the cell wall of plants (pectin) or algae (alginate) or starch and its derivatives offer numerous possibilities for the preparation of materials with controlled size, morphology, surface and structural properties.

Our project will be based on thorough characterization of the respective natural substances (mostly plant derived polysaccharides and other plant-based components), and their use as building blocks for self-assembly or targeted organization. The acquired supramolecular structures will serve as stand-alone encapsulants, as well as dedicated structural templates for a wide variety of microbial encapsulation approaches in order to suit to products, which are intended for ingestion and / or for contact with foodstuffs. The selected carriers will be used for two markedly different end-use applications, i.e. (i) for encapsulation of yeasts for optimized ethanol production, (ii) and to improve gut retention and act as a prebiotic for our own isolates of lactobacillus probiotics. In both cases, we will determine the encapsulation efficiency parameters, the level of supported and sustained microbial activity, as well as at the cellular level, the capability of the encapsulation system for fermentation or targeted  delivery of microorganisms.

The research project will set out to reach beyond the established alginate hydrogel systems using plant derived materials with more precisely defined surface characteristics in order to study the overlying physical, chemical and biological mechanisms that govern the efficiency of the microencapsulation process. We will employ and extend recent advances in the field of material science in order to generate in depth knowledge to allow for the design of food safe encapsulation carriers, perform through characterisation and material screening, as well as assess the suitability of such microencapsulated biomass for tacking current specific field issues using model microbial probiotics and food fermentation systems.

THE PHASES OF THE PROJECT AND THEIR REALIZATION

The research work is be organised within the following work packages:

• WP0: Coordination, project management and dissemination
• WP1: Preparation of carrier materials and development of encapsulation procedures
• WP2: Characterisation of encapsulation procedures
• WP3: Development of probiotics
• WP4: Process optimisation of fermented drinks

The project lasts three years. During the first year (0–12M) we will prepare and characterize the basic building blocks (using native forms of β- and α- or γ-cyclodextrins), develop basic processes for the preparation of empty materials (from 3 to 5 process variants) and carry out preliminary encapsulations with unmodified materials.  In the second and third year, we will continue to encapsulate with advanced materials and processes and, if necessary, carry out additional functionalization (3–7 functionalized forms or induced morphologies). Furthermore, a screening analysis will be employed (12–30M), in order to select the most suitable candidate for use in further applications. For this purpose, we will characterize the surface properties of model microbial cultures in advance and determine the possible and necessary forms of functionalization. As part of the analysis, we will compare different methods of preparation (for electrospraying and microsphere/microcapsule preparation, 4 to 8 final formulations), microorganism concentration (three to four concentration ranges), single-cell vs. multi-cell capsulation (4 to 5 size classes in the domain > 1 mm to ~ 1 μm) and varied particle surface properties (especially zeta potential), depending on the observed cell culture properties, as well as of the number of the functionalized building blocks. In the second half of the second year, we will start with testing for probiotics and fermentation. If necessary, the encapsulation procedures or the materials will be modified (18–36M). Process optimization and development of probiotics will be carried out and completed in the third year (24–36M). It is assumed that from 5 to 10 samples will be tested for each type of application. Characterization of materials and processes will be carried out simultaneously with the associated activities.

Bibliographic references

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