Encapsulation of Food Antioxidants
as Potential Functional Food
Ingredients
Amyl Ghanem Ph.D. P.Eng.
Chemical Engineering
Dalhousie University
Health benefits of plant polyphenols
– Plant polyphenols possess a high spectrum of
antioxidant, anti inflammatory anti bacterial and
antiviral functions.
– Research suggests that plant polyphenols can slow
the progression of certain cancers, reduce risk of
cardiovascular disease, neurodegenerative
disease, diabetes, osteoporosis etc.
Challenges
• Concentrations that are effective in vitro are often an
order of magnitude higher than in vivo.
• Low bioavailability of polyphenols
• small proportion of the molecules ingested orally actually make
it into bloodstream
• short gastric residence time, low solubility/permeability in the
gut or degradation due to enzymes, pH etc. in the GI tract.
• Instability of molecules during food processing and
storage
• degradation due to exposure to light, oxygen, temperature.
“Microencapsulation*”
Technically the formation of a wall material around a core/active material to make a
capsule, on the scale of 1-1000 microns. However this term has come to encompass
“entrapment” as well, Which includes the distribution of the core/active material
within a matrix:
wall
matrix
Core/active
active
Objective:
• Protect the core/active material from degradation in storage, processing or
active conditions
• Improve bioavailability, cell uptake of core/active material
• Act as a slow release reservoir
• Improve solubility of core/active material
• target delivery of core/active material to a specific location
*Nanoencapsulation applies
similarly to a nano-size range
Encapsulate or entrap plant extracts in
microparticles/nanoparticles
• Achieve high concentration of active molecules in small
volume.
• Matrix material would stabilize polyphenols during storage
and processing.
• Matrix material could be used to improve bioavailability.
• Applications exist in food, pharmaceutical and cosmetics
industries.
• Aim for particle size range < 30 mm or even lower not affect
texture or clarity.
My background:
Entrapment of molecules for Drug Delivery Systems
Purpose: to understand
and manipulate the fate
of drugs in humans.
• Controlled release
• Tissue targeting
Aicello Japan
Designed to release drug in the small intestine
Encapsulation Methods
–Spray drying
Widely used in the Food Industry
Common wall materials:
• Modified starch
• Maltodextrin
• Gum Arabic
Spherical particles
10-100 mm
Limitations: wall materials, high T
Freeze-Drying
Dehydration process good for heat sensitive materials
Active material and matrix material in solution
Results in powder of “uncertain form”
Great potential to combine with other methods
Cloudberry extract with Maltodextin
Lane et al, Agricultural and Food Chemistry
2008:11251-11261
– Ionic interactions: Coacervation, Gelation
Active molecule + matrix material
Counter ion solution
Microcapsules with
entrapped active molecule
Gel in solution deposits around the
active ingredient which is
suspended
• Gelatin
• Calcium alginate
• Chitosan
Considered expensive but does not
involve high temperatures or
solvents.
Control sizes from nano to micron
sized
-Liposomes
Lipid bilayer membrane encapsulating
an aqueous phase
Formed from phospholipids utilizing hydrophobic/hydrophilic interactions
Formed by:
thin film evaporation, sonication, reverse phase evaporation,
melting, freeze thawing, extrusion
A lot of literature on this technique
Shown to improve bioavailability and targeting
Often low entrapment efficiency and loading
Rapid release of active material
Can be improved by coatings
Fang and Bandhari, Trends in Food Science and
Technology 21(2010) 510-523
– Inclusion Complex
• Using cyclodextrin as an encapsulating material
• Hydrophobic/hydrophilic areas helps to improve the water solubility of
molecules.
– Emulsification
•
•
•
•
Active material dispersed into matrix/wall material
emulsified and cooled; Or
evaporation of internal phase
Lipids, hydrophilic polymers such as gelatin, glucan or agarose
– Thermal gelation
– Supercritical fluid
– Combinations of techniques, crosslinking, coatings
etc.
Fang and Bandhari, Trends in Food Science and
Technology 21(2010) 510-523
My background:
Entrapment of molecules for Drug Delivery Systems
• Matrix material: chitosan
• Active material
–
–
–
–
BSA (sample protein)
Glucose oxidase (sample enzyme)
Cladribine, adenosine (nucleotides, anticancer drug)
bFGF (growth factor)
• Methods:
– Complex coacervation of CH and TPP
– Crosslinking with gluteraldehyde, glyoxal, genipin)
Chitosan Nanoparticles (CH NP)
Unmodified, unloaded CH
Nanoparticles (112 nm 13)
Unmodified chitosan loaded with
100 ng of bFGF
87,000 x magnification
(157 nm  23)
N-succinyl Chitosan,
unloaded, dried
Magnification 16,500 ×
(642 nm  90)
Particle Properties
• Sizes: Microparticles and Nanoparticles
– 100-150 nm when dried (swell to 500 nm)
– Smooth spherical morphology
– Some aggregation observed
• Good loading efficiencies
– 70% for cladribine (anticancer drug)
– 50% for bFGF (growth factor)
• Can manipulate to modify behaviour
– Crosslinking (ionic, glyoxal, genipin)
– Modification (N-succinyl chitosan)
Controlled Release
Overall release from crosslinked Cladribine-loaded nanoparticles into PBS, pH 7.4.
180
Genipin Crosslinked (2 h, 0.1 mg/mL genipin)
160
Glyoxal Crosslinked (2 h, 50 mg/mL glyoxal)
Cumulative CdA Release (%)
140
120
100
80
60
40
20
0
No entrapment
0
20
40
60
Time (h)
Domaratzki, A and Ghanem, A.
Journal Applied Polymer Science 2013, 128: 2173–2179
18
80
100
120
bFGF release from nanoparticles into PBS, pH 7.4
chitosan
CH
CH+heparin
SCH
SCH+heparin
bFGF Released (% of entrapped)
25.0%
N succinyl chitosan
20.0%
+heparin
15.0%
10.0%
5.0%
0.0%
0
50
100
150
Time (hrs)
19
200
250
Examples of Polyphenol Entrapment
Encapsulation of anthocyanin extract from jabuticaba
and storage stability
Extracts by supercritical CO2, compared storage conditions of 3 systems
at 14 days:
Encapsulation
Efficiency
Degradation
25 oC
light
Degradation
25 oC
No light
Degradation
4o
No light
Free
anthocyanin
-
60%
~50%
~50%
Polyethylene
glycol
79.78%
60
30
~0
Ca-alginate
system
98.67%
25
20
~0
Both encapsulated systems were more stable under light and temperature
Santos et al, Food Research International, 2013:617-624
Spray drying of blueberry extract
•
•
•
Freeze dried blueberry, and blueberry pomace extracted into acetone (A), ethanol
(E) or methanol (M)
Spray dried with whey protein or gum arabic
Subjected to in vitro digestion model
Encapsulation
Efficiency
(TPC)
Antioxidant activity
during digestion
(Frap % 2hours)
Antioxidant activity
during digestion
(Frap %4hours)
Gum Arabic
A
E
M
68
106
95
~65
87
90
~30%
35
30
Whey Protein
A
E
M
53
137
102
65
85
85
55
80
85
No comparison to Free extract
However they did show that WPI preserved antioxidant activity during simulated digestion
Flores et al, Food Chemistry, 2014:272-278
Possible applications to Haskap
• Currently investigating extraction of blueberry
polyphenols and encapsulation by spray drying and
freeze drying
• Steps: what concentration can be achieved in the
extract?
• Recommend a combination of methods to achieve high
entrapment, stability and bioavailability
• Main variables would include material(s), extraction
method for polyphenols, encapsulation
• Encapsulation facilities
– spray drying, freeze drying, liposome formation,
coacervation
References
• Encapsulation of Natural Polyphenolic Compounds: A Review. Munin, A.
and Edwards-Levy, F. Pharmaceutics. 2011:793-829.
• Encapsulation of Polyphenol- a Review. Fang, Z and Bhandari, B. Trends in
Food Science and Technology 2010:510-523.