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Microencapsulat ion of probiot ic bacteria

Dimitris Charalampopoulos Department of Food and Nutrit ional Sciences

Health benefits of prebiotics The concept of probiotics and prebiotics

SCFA

peristalsis

prebiot ics

selective fermentation

improved bowel habit

reduced cancer risk and IBD inflammation

colonocytes

increased mineral absorpt ion

antagonism of pathogens and putrefactive bacteria

fewer toxic bacterial metabolites

reduced pH

Ca ++ Mg ++

reduced cancer risk

trophic and anti - neoplastic effects

induce

de novo lipogenesis

controlled serum lipids and cholesterol

Modified from Crittenden, In: “Prebiotics: Development and Application” (2006) 2

probiot ics

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

Survival of free probiotic cells in fruit juices

0.001.002.003.004.005.006.007.008.009.00

0 1 2 3 4 5 6 7

log

10 (C

FU/m

L)

Storage time (weeks) Orange juice Cranberry juice Grapefruit juiceBlackcurrant juice Pineapple juice Pomegranate juice

4 International Journal of Food Microbiology, 146, 111-117 (2011)

• Loss of viability in the stomach before action in intestine

5

Oral administration of live bacteria

Materials for encapsulation

• Alginates • Pectinates • Xanthan gum • Gum acacia • Guar gum • Carrageenan • Casein • Gelatin • Whey proteins

Technologies: Extrusion, Emulsion Coating technologies

Significant amount of literature

Capsules’ characterist ics Size Porosity Physical properties

Journal of Controlled Release, 162, 56-67 (2012)

Encapsulation of probiotics Bacterial dispersion in sodium alginate solution

Extrusion into CaCl2 solution

Alginate bead with encapsulated bacteria

Coating with chitosan

OOC -

COO -

COO -

COO -

COO -

COO -

OOC -

OOC -

COO -

COO -

COO -

COO - COO -

OOC -

NH3 +

NH3 +

NH3 +

NH3 +

NH3 +

NH3 +

Drying

Coat thickness as a function of chitosan exposure time

8

Chitosan labelled with fluorescein isothiocyanate Depth of penetration investigated by confocal microscopy

Biomacromolecules, 12, 2834-2840 (2011)

Viability of free and encapsulated B. breve in simulated model gastric solution

9 Biomacromolecules, 12, 2834-2840 (2011)

Release of cells during exposure to simulated gastric and intestinal solutions

10 Biomacromolecules, 12, 2834-2840 (2011)

Understanding the mechanism of protection against acid

pHrodo FITC

Biomacromolecules, 14, 387-393 (2013)

Understanding the mechanism of protection against acid

Biomacromolecules, 14, 387-393 (2013)

Methods for drying the microcapsules

Problems: • flat beads sticking together; • slow process; • not scalable; •clumping

Air drying

Fluidised bed drying

Wet alginate beads

Biomacromolecules, 12, 2834-2840 (2011)

Stability of fluid bed dried encapsulated cells during accelerated storage

14

0

2

4

6

8

10

12

0 3 10 14 20 45

Vi

abili

ty o

f bac

teria

CFU

/g

Days

0.23 Aw + 37°C 0.11 Aw + 37°C 0.23 Aw + 30°C 0.11 Aw + 30°C

Food Research International, 74, 208-216 (2015)

Survival in fruit juices - Cranberry juice L. plantarum

B. longum

pH ~2.8

Food Research International, 53, 304-311 (2013)

Protection against phenolics

Uncoated

2 h.

The beads were in 1% gallic acid 1 h (pH =3) and then Folin–Ciocalteu reagent was added to form the colour

Control

UN S D

UN S D

Food Research International, 53, 304-311 (2013)

Microencapsulation of a synbiotic (probiotic + prebiotic) into PLGA/alginate multiparticulate gels

17 International Journal of Pharmaceutics, 466, 400-408 (2014)

Prebiotic galacto-oligosaccharide (GOS)

Release of GOS from PLGA microparticles

18 International Journal of Pharmaceutics, 466, 400-408 (2014)

Release of GOS from PLGA/alginate (blue diamonds) and PLGA/alginate–chitosan (red squares) multiparticulates

19

500 μm 50 μm 20 μm

20 μm20 μm400 μm

International Journal of Pharmaceutics, 466, 400-408 (2014)

Release of probiotic from PLGA/alginate multiparticulates

20 International Journal of Pharmaceutics, 466, 400-408 (2014)

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