Microencapsulation of probiotic bacteria

Transcription

1 Microencapsulation of probiotic bacteria Dimitris Charalampopoulos Department of Food and Nutritional Sciences

2 Health benefits of prebiotics The concept of probiotics and prebiotics reduced cancer risk and IBD inflammation improved bowel habit de novo lipogenesis controlled serum lipids and cholesterol colonocytes trophic and anti - neoplastic effects induce peristalsis SCFA Ca ++ Mg ++ reduced ph increased mineral absorption prebiotics selective fermentation antagonism of pathogens and putrefactive bacteria fewer toxic bacterial metabolites probiotics reduced cancer risk Modified from Crit tenden, In: Prebiotics: Development and Application (2006) 2

3 Potential of encapsulation and challenges Prolong survival during long term storage of probiotics in dried form (refrigerated and ambient temperature) Prolong survival during food processing and storage in food products (dairy, juices, chocolate, etc) Ability to target delivery / control release in the GIT (e.g. small intestine, large intestine) Scalability and costs Minimise negative organoleptic effects 3

4 Survival of free probiotic cells in fruit juices log 10 (CFU/mL) Storage time (weeks) Orange juice Cranberry juice Grapefruit juice Blackcurrant juice Pineapple juice Pomegranate juice International Journal of Food Microbiology, 146, (2011) 4

5 Oral administration of live bacteria Loss of viability in the stomach before action in intestine 5

6 Materials for encapsulation Alginates Pectinates Xanthan gum Gum acacia Guar gum Carrageenan Casein Gelatin Whey proteins Significant amount of literature Capsules char act er ist ics Size Porosity Physical properties Technologies: Extrusion, Emulsion Coating technologies Journal of Controlled Release, 162, (2012)

7 Encapsulation of probiotics Bacterial dispersion in sodium alginate solution Extrusion into CaCl2 solution - OOC - OOC - COO - COO - COO - COO - COO Drying + NH3 - OOC + NH3 + NH3 - COO - COO - COO Alginate bead with encapsulated bacteria - OOC - COO + NH3 - COO + NH3 + NH3 Coating with chitosan

8 Coat thickness as a function of chitosan exposure time Chitosan labelled with fluorescein isothiocyanate Depth of penetration investigated by confocal microscopy Biomacromolecules, 12, (2011) 8

9 Viability of free and encapsulated B. breve in simulated model gastric solution Biomacromolecules, 12, (2011) 9

10 Release of cells during exposure to simulated gastric and intestinal solutions Biomacromolecules, 12, (2011) 10

11 Understanding the mechanism of protection against acid phrodo FITC Biomacromolecules, 14, (2013)

12 Understanding the mechanism of protection against acid Biomacromolecules, 14, (2013)

13 Methods for drying the microcapsules Wet alginate beads Air drying Problems: flat beads sticking together; slow process; not scalable; clumping Fluidised bed drying Biomacromolecules, 12, (2011)

14 Stability of fluid bed dried encapsulated cells during accelerated storage Aw + 37 C 0.11 Aw + 37 C 0.23 Aw + 30 C 0.11 Aw + 30 C Viability of bacteria CFU/g Days Food Research International, 74, (2015) 14

15 Survival in fruit juices - Cranberry juice L. plantarum ph ~ 2.8 B. longum Food Research International, 53, (2013)

16 Protection against phenolics Control UN S D 2 h. UN S D Uncoated The beads were in 1%gallic acid 1 h (ph =3) and then Folin Ciocalteu reagent was added to form the colour Food Research International, 53, (2013)

17 Microencapsulation of a synbiotic (probiotic + prebiotic) into PLGA/alginate multiparticulate gels Prebiotic galactooligosaccharide (GOS) International Journal of Pharmaceutics, 466, (2014) 17

18 Release of GOS from PLGA microparticles International Journal of Pharmaceutics, 466, (2014) 18

19 Release of GOS from PLGA/alginate (blue diamonds) and PLGA/alginate chitosan (red squares) multiparticulates 500 μm 50 μm 20 μm 400 μm 20 μm 20 μm International Journal of Pharmaceutics, 466, (2014) 19

20 Release of probiotic from PLGA/alginate multiparticulates International Journal of Pharmaceutics, 466, (2014) 20

21 Future research Develop small size microcapsules that offer good protection and understand the influence of size and physiochemical properties on the organoleptic properties of the food Develop scalable technologies Design and develop encapsulation that can deliver probiotics and prebiotics and specific areas of the GIT Study the delivery/release of the microcapsules in animal models of inflammatory bowel disease (e.g. Crohn s disease and ulcerative colitis) and human trials