Use of irradiation, for the development of active

edible coatings, beads and packaging to assure

food safety and to prolong the preservation.

Monique Lacroix, Ph.D.

Professor

Fellow of the International Academy of Food Science

and Technology

Director

Research Laboratories in Sciences, applied to food

Canadian Irradiation Centre

INRS-Institut Armand-Frappier

531 des prairies blvd.

Laval Québec Canada H7V 1B7

450-687-5010, poste 4489

Monique.lacroix@iaf.inrs.ca

Web :www.iaf.inrs.ca

Web :www.labo-resala.com

Global market of packaging

$ 417 Billion

100 000 industries

Food Packaging represent

65% of the market

Paperboard: 36%

Plastic: 35%

Glass, composites, wood etc. 29%

Current global consumption of plastics

200 million tonnes/year

Annual growth: 5%

PET; PVC; PE; PP; PS; PA

New regulations

In Canada, every company has to pay 50% of the

cost of collection and recycling

Demand for the use of biopolymers is growing

Challenges

• Bio-based packaging is defined as packaging

containing raw materials originating from

agricultural sources

• Proteins based films have high moisture

sensitivity and a variable gas and water

permeability

• Polysaccharides can improve the emulsion

capacity but reduce the water resistance

• Lipid can improve the elasticity and improve the

water resistance

Nanocellulose and Food Packaging Nanocomposite: New generation of polymer

Nanocellulose has

Low thermal expansion coefficient

High strength and modulus

Can act as reinforcing material

Potentially

Assure a control release of active compounds

Modulate the barrier properties

The stability should be demonstrated

when in contact with the food

Some of the limited mechanical and barrier properties of

biopolymers can be significantly enhanced by the use of

reinforcing fillers like nanocellulose

Ionizing irradiation

Ionizing irradiation can plays a major role in

the development and improvement of

packaging polymers properties as well as

sterilizing material used in aseptic

packaging.

Enhance barrier, adhesion, mechanical

properties, thermal stability

Advantages of irradiation:

Crosslinking, Grafting and

compatibilization

Formation of strong bridges between macromolecules

Compatibilization of polymer blend by high energy radiation

Addition of multifunction monomers and inomers to polymer blends in order to accelerate and increase the crosslinking degree in polymer blends

Post-process contamination

66% of the post-process contamination is

caused by

Product mishandling

Faulty packaging

Active packaging and coating can interact

with the food and have been proposed as

innovative technologies

Natural Antimicrobial Compounds

Replace synthetic compounds by natural compounds

Advantages

Scientific Challenges

Instability during time and depend on the food

composition

The immobilisation in polymers is a good

alternative

Natural antimicrobial compounds under consideration

• Bacteriocins (ex: Nisaplin® nisin, pediocins)

• Spice and herb extracts

• Organic acids

nisin

Thymol

Crosslinking Reaction

of bio-polymers

with γ- Irradiation

0

500000

1000000

1500000

2000000

2500000

3000000

3500000

4000000

0 8 16 32 64 92 128

Flu

ore

scen

ce i

nte

nsit

y (

a.u

)

Dose (kGy)

Base

PEG

Sor

Man

Formation of bityrosine in

calcium caseinate based-films

as a function of irradiation dose

An increase by 10-60 times the molecular weight by irradiation

1: CC-WPI

2: CC-WPI-PS

3: CC-WPI-SPS

4: CC-WPI-Alginate

J.Sci.Agric.2006:908-914

Effect of gamma irradiation on

the puncture strength and

On the WVP of

Protein-Polyssacharides based

edible films

0

10

20

30

40

50

60

70

80

4 8 16 32 64 96 128

Dose (kGy)

Weig

ht

yield

(%

)

Fraction of insoluble matter in function of the irradiation dose

Results are expressed as the percentage in solid yield after

soaking the films 24 hours in water

Films based on crosslinked caseinate (32 kGy) in presence of pepper and oregano:

E. coli growth on fresh meat

2,0

2,2

2,4

2,6

2,8

3,0

3,2

3,4

3,6

3,8

4,0

0 2 4 6 8Temps (jour)

Lo

g U

FC

/CM

2 Control Control + pepper

Oregano + pepper

Oregano

Bilayer films based on

Proteins

methyl cellulose / carboxymethylcellulose

polycaprolactone

effect of crosslinking reaction using γ-irradiation

16

20 22

28

25

22 22 26

30

33

41

37

33

29

0

10

20

30

40

50

0 5 10 15 20 25 30

Tensi

le S

trength

(M

Pa)

Total Dose (kGy)

PCL Composite

35% increase

Effect of gamma radiation on tensile strength

of PCL/NCC based films

Khan et al., 2013 J. Appl. Polymer Sc. 129, 5, p. 3038-3046

58% increase

555

620

834

900

865 860

778

418

512

720

998 973

912

856

0

300

600

900

1200

0 5 10 15 20 25 30

Elo

ngati

on a

t B

reak

(%

)

Total Dose (kGy)

PCL Composite

Effect of gamma radiation on elongation at break of

PCL / NCC based films

Khan et al., 2013 J. Appl. Polymer Sc. 129, 5, p. 3038-3046

Effect of Bioactive films based on crosslinked

proteins, MC and ε-Polycaprolactone-diol

on Salmonella Typhimurium on Broccoli

Takala et al., 2013 J.Food Eng. 648-655

Irradiation to produce grafting

NCC-reinforced MC-g-TMPTMA films

NCC-reinforced MC-g-TMPTMA films

TMPTMA : Contains 3 reactive methacrylic acid residues

Wide acceptance as a cross-linker and plasticizer

Probable grafting mechanism

Reaction of OH groups from MC with the vinyl groups

of TMPTMA during exposure to ɣ-radiation

Formation of a grafted complex

Low dose irradiation to prevent polymer degradation

and by-products O

O

O

O

O

O

CNC-reinforced MC-g-TMPTMA films

Optimal concentration of TMPTMA : 7% (w/w, dry basis)

Optimal irradiation dose : 5 kGy

Incorporation of NCC into MC bulk (10-30% w/w, dry basis) allowed a

remarkable improvement of :

- Mechanical properties (+ 94-126% in PS)

- WVP (- 25%)

- Thermal properties (crystallinity )

CNC-reinforced MC-g-TMPTMA films

Combined effects of CNC filling/ɣ-radiation dose on the mechanical

properties of grafted films

Effect of NCC concentration combined with ɣ-radiation doses on the TS of MC-

g-TMPTMA (7%) films.

Effect of radiation:

TS up to 5 kGy and then

(degradation of the film)

Effect of radiation/NCC filling:

TS up to 1 kGy/10% CNC

Optimal TS = 67 MPa (+ 76%)

Synergy between grafting

and NCC addition

Control

10% CNC

20% CNC

30% CNC

Irradiation to produce

Crosslinked coating polymers

Effect of crosslinked coating based on proteins/MC and limonene

on rotting fruits (%) during storage at 4 ºC

0

10

20

30

40

50

60

70

Day 7 Day 10 Day 14 Day 17

control

coating

coating+L

Beads based on alginate and

nanocrystal cellulose

Effect of ϒ-irradiation on swelling and

application on food system

Time (h)

Sw

ell

ing

(%

)

50

100

150

200

250

300

350

0%NCC

1%NCC

3%NCC

5%NCC

8%NCC

81 2 4

5wt% NcC decrease by 53% the swelling of beads

Effect of nanocrystal cellulose on beads sweeling

Beads based on alginate and nanocrystal cellulose

Effect of irradiation on beads swelling

Huq et al. (2012) Rad. Phys. Chem. 81, 945-48.

A dose of 0.5 kGy decreased by 25% the sweeling of beads

Effect of NCC content (w/w%) on a)

tensile strength (MPa), b) tensile

modulus (GPa) and c) elongation at

break (%) of alginate-based film, as a

function of NCC content in dry matrix of

alginate-based film

NCC Content (w/w%) in Alginate-Based Film

0 2 4 6 8 10

Te

nsil

e S

tre

ng

th (

MP

a)

50

55

60

65

70

75

80

85

NCC Content (w/v%) in Alginate-Based Film

0 2 4 6 8 10

Ten

sil

e M

od

ulu

s (

MP

a)

1600

1800

2000

2200

2400

2600

2800

3000

3200

3400

NCC Content (w/w%) in Alginate-Based Film

0 2 4 6 8 10

Elo

ng

ati

on

at

Bre

ak (

%)

4

5

6

7

8

9

10

11

TS 5wt% NCC increase 37%

TM 5wt% NCC increase 75%

Eb 5wt% NCC decrease 44%

Mechanical properties of films

based on NCC/alginate

Development of Cellulose Nanocrystal (CNC)

Reinforced Bio polymeric Matrix for Encapsulation of

Bioactive Compounds

Encapsulation of Antimicrobial

Compounds in beads based on alginate-NCC

HAM without

Microbead

HAM with

Microbead

Cooked

HAM

HAM Application

Antimicrobial properties of the CNC reinforced alginate beads on ready-

to-eat (RTE) meat against Listeria monocytogenes

Growth of L. monocytogenes on vacuum packaged

cooked ham slices coated with non-

microencapsulated nisin at 4° C

Growth of L. monocytogenes on vacuum packaged

cooked ham slices coated with microencapsulated

nisin at 4° C

Crosslinked active beads by

ϒ-irradiation

and

ϒ-irradiation of meat

coated with the active beads

Evaluation of the synergistic effect on

pathogens elimination

Example of bacterial radiosensibilization in meat

Salmonella

0

1

2

3

4

5

6

0,00 0,25 0,50 0,75 1,00 1,25 1,50 1,75 2,00 2,25

Irradiation dose (kGy)

Log

CF

U/g

0

1

2

3

4

5

6

0,00 0,25 0,50 0,75 1,00 1,25 1,50

Irradiation dose (kGy)

Log C

FU

/g

Air MAP

Thyme Thyme

Control Control

20 times 5 times

D10 (kGy) RS

C 0.57±0.031a 1±0.00a

CN+N 0.16±0.001e 3.57±0.15g

CN+N (E) 0.08±0.002f 6.89±0.30h

D10 and Radiosensitivity (RS) for non and

microencapsulated antimicrobial microbeads against

L.monocytogenes*

*Values are means ± standard deviations. Means with the same letter are not significantly different (P > 0.05). Food Microbiology 2015, 46, 507-514.

An increase of the bacterial radiosensitization can

permit to reduce the dose needed to eliminate

pathogens

Active films based on crosslinked chitosan-NCC

and nisin on total microflora on ham

0

2

4

6

8

10

0 7 14 21 28 35

Bacte

rial

cou

nt

(Log C

FU

/g)

Storage (days)

Meat G-1.5kGy

Meat+1.5 kGy Acceptable limit

Population of mesophilic bacteria in fresh pork

during storage at 4°C

Innovative Food Science and Emerging Technologies. 2016, 35, 96-102

Conclusions

Crosslinking and graft copolymerization by

ϒ-irradiation and the development of nanocomposites

Can improve the physico-chemical, the water resistance

and barrier properties (WVP) of the films, beads and

coating and can assure a better control of the active

compounds release during storage.

Antimicrobial edible crosslinked films, coatings and

beads can also act in synergy with γ-irradiation on food in

order to eliminate pathogens, assure food safety and can

increase the food shelf life.

Microencapsulation technology combined with irradiation

could be an advanced process to improve the food safety.

Contact:

Monique Lacroix, Ph.D., Professor

INRS-Institut Armand-Frappier

Research Laboratories in Sciences Applied to Food

Canadian Irradiation Centre

531, Bd des prairies, Laval, QC, H7V 1B7, Canada

Tel: 450-687-5010 #4489 ; Fax: 450-686-5501

E-mail: monique.lacroix@iaf.inrs.ca

Web: www.iaf.inrs.ca

Research Laboratories in Sciences

Applied to Food

Canadian Irradiation Centre Dr Marcel Gagnon

1927-1993