1. CONTROLLED RELEASE FOOD PACKAGING
Seyhun Gemili
March 23rd, 2009

2. OUTLINE Packaging Packaging Materials Active Agents
Importance of Controlled Release
Controlled Release Techniques
Mathematics of Diffusion
Conclusion

3. Packaging Packaging is the science, art, & technology
It also refers to the process of design, evaluation, and production of packages
Many cooking & preservation processes still largely depend on effective packaging
O2, light, WV, bacterial and other contaminants can effect the products

4. Packaging Materials GLASS METAL PAPER PLASTIC Advantages Disadvantages
Excellent barrier against O2 & moisture
Easily breakable
Relatively heavier
METAL
Excellent barrier against O2, moisture, & light
Good mechanical strength and durability
Good thermal stability
Susceptible to corrosion
Metal cans are generally more difficult to open and reseal
PAPER
Relatively inexpensive
Excellent printability
Lightweight
Poor gas and moisture barrier
Greatly reduced mechanical strength when wet
PLASTIC
Most versatile packaging material
Can be formed easily into many shapes
More susceptible to migration and flavor-scalping problems

5. Natural Polymers (Environmental issues)
Polymers or long-chain macromolecules that can be molded, extruded, cast into various shapes
Polyethylene (PE)
Polypropylene (PP)
Polyvinyl Chloride (PVC)
Natural Polymers (Environmental issues)
Starch
Protein
Cellulose
poor O2 & moisture barrier
weak mechanical strength

6. Active Packaging
Active packaging is an innovative food packaging system
Categories for active packaging techniques are
Absorbing
Releasing
Other (Self heating & self cooling packaging)

7. Active Agents for Releasing Systems
Antimicrobial Agents
Organic acids
Sorbate
Propionate
Benzoate
Bacteriocins
Nisin
Pediocin
Enzymes (high cost)
Lysozyme
Antioxidant Agents
BHT (phsiological effects)
Vitamin E
Vitamin C

8. Clear zones of inhibition of the
spoilage bacteria Brochothrix
thermosphacta around discs of
whey protein film containing
lysozyme after 48 hr at room
temperature

9. Controlled Release Packaging Sytems
Controlled release is mostly applied in pharmaceutical industry
Controlled release packaging (CRP) is a new generation of packaging materials
CRP is attractive for controlling food degradation reactions
Release rate of active agents is the most critical factor
Controlled release of active agents is highly desirable

10. Releasing Systems Contact w/ the food surface
Diffusion b/w the packaging material & food
Active agents have to be volatile

11. Different delivery modes of nisin
LaCoste et al. 2005
■ Instant addition of nisin into broth medium
▲Slow addition of nisin into broth medium
▼Combination of the above two delivery mode
● The control
Different delivery modes of nisin

12. Different Techniques
Mono- and multilayer active films containing lysozyme as antimicrobial agent (Buonocore et al. 2005)
Sample
Monolayer
Multilayer
Containing lysozyme
Layer 1
Layer 2
contaning lysozyme
Layer 3
Film A
Cross-link A
Film B
No cross-link
Film C
Fiilm D
Cross-link B
Cross-link A: 0.077% of glyoxal
Cross-link B: 7.7% of glyoxal

13. (●) film A (○) film B (■) film C (□) film D
Different Techniques
Amount of lysozyme released from 4 different films plotted as a function of time
(●) film A (○) film B (■) film C (□) film D

14. Different Techniques smart blending (LaCoste et al. 2005)
Multilayer morphology
Selective permeable morphology
Interpenetrating (sponge) morphology
Fibrous morphology
Conducting morphology

15. Mathematics of Diffusion
Assumptions
Well stirred limited volume of solution
No chemical rxn b/w active compound & the film
Mass transfer in the film takes place only by diffusion
Diffusion coefficient of active compound in the film is constant

16. Mathematics of Diffusion
Crank 1975
……………………………………………
……………………………..……………... 2
………….. 3

17. Mathematics of Diffusion
…..…………………
………………………………………………
………………………….……..…

18. Mathematics of Diffusion
………….. 7
Amount of solute leaving the film up to time t
Amount of solute leaving the film at eq.
Partition factor
Non-zero positive root

20. Conclusion
More information is needed about the chemical, microbiological and physiological effects of various active concepts on the packaged food
There are various methods and their testing in a model system, but not much in real food products. Models should be developed for real food systems.
Some researchs have to be done to identify the types of food that can benefit most from active packaging

21. Thank You