3. Edible films

New delivery systems for probiotic
digestive health products
Christos Soukoulis
Senior researcher (PhD)
Public Research Centre – Gabriel Lippmann, Luxembourg
Department of Environment and Agro-Biotechnologies
Nutrition and Food Science Area
1
Outline of the presentation
1. Introduction – General remarks on probiotics
2. Advances in probiotic encapsulation technologies
3. Edible films: can they promote probiotic efficacy?
4. Probiotic food product prototyping based on edible films
5. Future perspectives and conclusions
2
1.1 What are probiotics?
Probiotics are defined as:
“live organisms which when administered in adequate amounts
may confer a beneficial effect to the human host”
WHO/FAO (2002)
Examples of probiotic microbiota:
• Lactic acid bacteria (Lactobacilli)
L.acidophilus, L. casei, L. rhamnosus, L. plantarum, etc.
• Bifidobacteria
B. bifidum, B. breve, B. longum, B. lactis
• Yeasts
Saccharomyces boulardii
• Other LAB species
Streptococcus thermophilus, Lactococcus lactis , Leuconostoc
faecium etc.
mesoenteroides, Enterococcus
3
1.2 Why probiotics?
Health benefits associated to probiotics ingestion:
Relief of inflammatory bowel disease
Reduction of the recurrence of Clostridium difficile diarrhoea
Modulation of gut microflora
Stimulation of immune system
Treatment of acute rotavirus diarrhoea
Antagonistic action towards
Treatment of antibiotics associated diarrhoea
gastrointestinal pathogens
Reduction of LDL-cholesterol
Prevention of lactose intolerance implications
Recovery of ulcerative colitis
•
•
•
•
•
•
•
•
•
Health benefits are generally dependent on:
•
•
•
•
•
Species and strain type
Amount of live cells administered via diet
Presence of probiotic growth stimulants e.g.
inulin, FOS, GOS etc.
Adopted processing and handling conditions
Characteristics of the food carrier
Saad et al., (2013)
4
1.3 Delevelopment of probiotic foods: Challenges for
the R&D scientist
Designing the food matrix/carrier to deliver probiotic efficacy is a rather complex task …

 
Soukoulis and Bohn
(2015)
Changes occurring
during GI passage
5
1.4 Which strain/species fits to my needs?
Selection
criteria
SAFETY
GRAS e.g.
Non-pathogenic
Non-toxic
Non-allergenic
IN-VIVO
VIABILITY
Good tolerance
to GI conditions
Gastric juice
Bile salts
Bile enzymes
Antagonism synergism with
colon microbiota
TECHNOLOGICAL
ASPECTS
HEALTH
POTENTIAL
Resistance towards
common processing
conditions
Clinically proven
functionality
Interaction with the
food matrix
Sensory aspects
Approved by EU
governmental
bodies e.g.
EFSA
Cost efficiency
Facile incorporation
6
1.5 Encapsulation: promoting bioactives stability
What is
encapsulation?
"Physical or chemical entrapment of a labile compound into
a dry or liquid matrix that creates a barrier against harsh
environmental conditions e.g. heat, pH, enzymes, light,
oxygen etc."
7
2.1 Probiotics encapsulation technologies
ANHYDROBIOTICS
COATED
PARTICLES
SPRAY
DRYING
SPRAY
CHILLING
EXTRUSION
FLUIDISED
BED
FLUIDISED
BED
COACERVATION
ELECTROSTATIC
LAYERING
FREEZE
DRYING
8
2.2 Recent advances in probiotics encapsulation
SUPERCRITICAL
FLUIDS
ELECTROSPINNING
Moolman (2006)
ELECTROSPRAYING
EDIBLE FILMS AND
COATINGS
NANOSTRUCTURED
POLYELECTROLYTE
LAYERS
Lopez Rubio et al., (2012)
SOLID LIPID
MICROCARRIERS
Soukoulis et al., (2014a)
Priya et al., (2011)
Soukoulis and Bohn (2015b)
9
3. Edible films: can they promote probiotic
efficacy?
Edible film: “Any type of material used for enrobing various food to extend
shelf life of the product that may be eaten together with food with or without
further removal”.
Light penetration
Water vapour and
gases permeability
SHELF LIFE
EXTENSION
Food product
surface coverage
EDIBLE
FILMS
Flavourings
Colorants
CUSTOMISED
STRUCTURE AND
MECHANICAL ASPECTS
Durability upon
handling
Tailored
organoleptic aspects
BESPOKE
FUNCTIONAL
ASPECTS
Antioxidants
Antimicrobials
Micro-nutrients
Beneficial microbiota
10
3.1 Probiotic edible films and coatings: the
concept
HYDROGEL
BASED
Polysaccharides
Proteins
Hydrophilic
bioactives
PROBIOTIC
GROWTH
STIMULANTS
Primary carriers
PLASTICISER
FREE RADICAL
SCAVENGERS
EMULSION
BASED
Mainly
biopolymer
stabilised o/w
emulsions
They allow the
delivery of
secondary
(synergistic)
compounds
e.g. lipophilic
polyphenols and
carotenoids
BLENDING
WITH
HARVESTED
PROBIOTICS
COLD CASTING
DRYING
11
3.2 Probiotic edible films and coatings:
advantages and disadvantages
PROBIOTIC EDIBLE FILMS
Pros







MAINTAIN TECHNO-FUNCTIONALITY OF CONVENTIONAL EDIBLE FILMS
ALLOW SUSTAINED RELEASE
INEXPENSIVE
VERSATILE
EASY-TO-MAKE
DO NOT REQUIRE SOPHISTICATED PROCESSING REMEDIES
SUSTAINABLE





Cons
SHELF-LIFE IS RESTRICTED COMPARED TO ANHYDROBIOTICS
ACUTE TOXICITY DUE TO OSMOTIC STRESS MAY OCCUR
DETERIORATION OF OPTICAL PROPERTIES e.g. opacity
SOLUTES MOLECULAR MOBILITY IS HIGH (RUBBERY THAN GLASSY STATE IS ACHIEVED)
PROBIOTICS VIABILITY IS STRONGLY DEPENDENT ON COMPOSITIONAL ASPECTS
APPLICATIONS
Mainly IMF foods
12
3.3 Some examples on probiotic edible films
A. ANIONIC POLYSACCHARIDES
WPC BASED
NO WPC
•
•
•
•
0.094 μm
5.02%
5.65
Higher Tg
•
•
•
•
0.108μm
6.40%
7.62
Improved mechanical
properties
13
3.3 Some examples on probiotic edible films
A. ANIONIC POLYSACCHARIDES
Survival
Storage
throughout
stabilitydrying
4°C
Promising for short shelf-life food applications
e.g. bakery
0.06 – 9.59%
4.75 – 86.02%
25°C
Addition of whey proteins improved the resistance of L. rhamnosus
14
3.3 Some examples on probiotic edible films
A. ANIONIC POLYSACCHARIDES
REDUCTION
OF SOLUTES
MOLECULAR
MOBILITY
FREE
RADICAL
SCAVENGING
ACTIVITY
HIGHER
AMOUNT OF
NUTRIENTS
REDUCED
GASES
PERMEABILITY
IMPROVED
ADHESION
ABILITY OF
PROBIOTIC
CELLS
BETTER
COATING OF
PROBIOTIC
CELLS
15
3.3 Some examples on probiotic edible films
B. STARCH BASED SYSTEMS
 No significant effect of starch type
on maintaining the probiotic
efficacy throughout drying
Rice
Rice
1
C_gel
C_NaCas
a*
%E
C_NaCasTS
PC2: 21.36%
L. rhamnosus GG
R_NaCas
R_gel
R_NaCas
C_gel
 Rice starch improved storage
stability of L. rhamnosus GG
 Presence of proteins enhanced
storage stability and viability of
R_gel
2
0
Viability loss at drying
WVP
Corn
-1
Tg
k4C
Corn
k25C
C_SPC
L*
b*
Opacity
 Protein performance followed
the order: NaCN>gelatine>SPC
 Storage stability was positively
correlated with glass transition
and negatively with starch
retrogradation phenomena.
-2
Thickness
R_SPC
C_SPC
R_SPC
-3
-5
-4
-3
-2
-1
0
1
2
3
PC1: 45.64%
Soukoulis et al., (2015)
16
3.3 Some examples on probiotic edible films
C. SYMBIOTIC FILMS
Microstructure
Survival throughout drying
Storage stability
Soukoulis et al., (2014a)
Estimated shelf-life:
17 – 100 days
Inulin: +123%
Wheat dextrin: +89%
GOS: + 36%
17
4. Probiotic food product prototyping based on
edible films: The case of pan bread
The concept:
 Preparation of a “probiotic fluid-hydrogel”
 Application by means of spraying on the crust of bread exiting the oven
 Rapid air drying (60°C, ventilated chamber – baking oven)
Lactobacillus
rhamnosus GG
Application of a
probiotic film forming
solution
Prebaked pan bread
•
•
Air drying
180°C for 2min
60°C for 10min
Pan bread
containing surface
coated probiotic
edible film
Soukoulis et al., (2014b)
18
4.1 Appearance and crust microstructure
No visual differences between probiotic and conventional breads were
detected
CONTROL
ALG@60°C
ALG@180°C
WPC@60°C
WPC@180°C
Whey proteins:
o Thicker films
o Better coverage of probiotic cells
19
4.2 Viability of probiotic cells
Viability throughout drying
Storage stability
---Lag phase---
Growth
***
Survival throughout
in-vitro digestion
NS
*
0.85
0.9
0.94
aw
One slice may deliver > 107 cfu
under simulated GI conditions 
20
4.3 Physical, thermophysical and textural
properties (bread staling)
NS
NS
NS
NS
ΔHretrogradation = 1.22-1.74 J/g
ΔHamylose-lipid = 3.97-5.65 J/g
Tglass transition = -31.9 to -30.9°C
21
4.4 Flavour profile of probiotic bread crusts
APCI-MS headspace fingerprinting of bread crusts
Bread staling
associated VOCs:
a) Depletion of "freshly
baked " flavour
descriptors
b) Development of "
LA fermentation "
associated VOCs
22
5. Conclusions and future perspectives

Edible films appear to be a viable carrier to provide probiotic efficacy in
functional foods

Most of the common biopolymers elaborated in food manufacture did not
exert any acute toxic effect on tested probiotic strain

Presence of proteins prominently improves survivability of probiotics

More research is required to elucidate the mechanistic basis of the viability
of probiotics in plasticised biopolymer matrices

Combination of common biopolymer with prebiotics improved the survival
in-vitro of L. rhamnosus GG

Other bioactives could be combined via the probiotic edible film
technology to provide multifunctional food matrices targeting colonic
nutrients absorption
23
Acknowledgements
Dr. Ian Fisk
Dr. Lina Yonekura
Ms. Solmaz Behboudi-Jobbehdar (MSc)
Ms. Poonam Singh (MSc)
Dr. Heng-Hui Gan
24
THANK YOU FOR YOUR ATTENTION !
25

Download Report