Modified Atmosphere Packaging Flashcards
What is “MAP?” What is its purpose?
gas barrier materials (selective permeability) to modify gaseous environment
-> extend shelf life
How does MAP extend shelf life?
alter gaseous environment:
- > slow microbe growth
- > slow respiration
- > retard enzymatic spoilage
the principles of MAP are based on:
Which is more stable/precise?
CA, MA storage
CA/MA is more stable/precise (cannot control package or environment conditions once exits factory)
The CA/MA inside the package is maintained by selective ____ of ____ into the package, and ____ out of the package.
diffusion
CO2
oxygen
Equilibrium is a balance between ___ ____ and ___ ____
product respiration; package permeation
What is critical to consider for MAP? Why?
temperature
affects both respiration and permeability rates
What are the aims of MAP concerning the gaseous environment?
reduce oxygen levels
increase CO2 levels
then maintain
What is the gaseous environment comprised of?
O2
CO2
N (filler)
What gas can be used to further improve CA?
CO (carbon monoxide)
What are some uncontrolled examples of MA?
airtight cold storage rooms film/wrap/bags PE liners in shipping containers pallet shrouds vents waxes plastic with diffusion windows
2 stages of MAP or MA:
- MA Generation
2. MA maintenence
How is the MA generated? (2)
- active process (commercially): GAS FLUSH: fast control of resp/ethylene, vacuum to remove toxic gases
- passive process: produce respiration (slow, some quality loss)
how is MA maintained?
selective permeability
What are various gas barriers present in the system?
commodity’s dermal system (natural skin)
coating (wax, film)
package
room
What causes the changing of gas atmosphere in passive process?
produce respiration: consume O2 (deplete), release CO2
True/false: With equal permeability, oxygen and CO2 flow rates are equal.
False
O2 = 16/10 CO2
What happens in a package with NO permeability?
CO2 cannot exit (accumulates), O2 depleted (O% oxygen)
- > puffing of package
- > fermentation
What happens in a package with equal permeability?
no change in gaseous environment
What permeability can maintain active MAP?
deltaC for O2: 16%
for CO2: 10%
What plastic has the lowest permeability?
saran (PVDC)
What plastic has the highest permeability?
LDPE (low density polyethylene)
What factors need to be considered with MAP?
Commodity factors (RQ, resp rate, type, maturity, quantity) film/package factors (type/structure, thickness, SA) environmental factors (temperature)
gas flux should be proportional to:
difference in concentration x permeability
constant K depends on:
surface area, thickness of film
respiration flux =
respiration rate x mass
What effect does temperature change have?
affect respiration rate, permeability
What happens if respiration is greater than permeation?
O2 will be depleted
accumulation of CO2
causes damage (cannot respire)
What happens if permeability is greater than respiration?
more O2, more CO2 released lose MA (ineffective)
What are the advantages of edible coatings? What are some examples?
provide MAP
moisture barrier
biodegradeable
methylcellulose, whey films
Active packaging is:
packaging with additional functions:
MAP
Moisture barriers
+ additional functions (antibacterial, antifungal, etc)
