microencapsulation of probiotic bacteria · 2017-12-21 · microencapsulation of a synbiotic...
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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)
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