This document provides an overview of modified atmosphere and modified humidity packaging. It defines these terms and discusses their commercial uses and principles. Modified atmosphere packaging involves exposing produce to a controlled gas mixture inside a sealed package to extend shelf life. Benefits include reduced respiration and ethylene effects, while risks include disorder development if not designed properly. Modified humidity packaging controls the relative humidity inside packages using additives like salts to prevent issues from very high humidity. The document outlines the key learning objectives and lessons that will be covered.

1. Lecture 6
POSTHARVEST CONTROL
OF SENESCENSE AND
RELATED PROCESSES

2. LEARNING OBJECTIVES
At the end of the lesson, the learners are expected to:
1. define modified atmosphere and modified atmosphere
packaging;
2. explain the commercial uses of modified storage
packaging;
3. Discuss the principles of modified atmosphere storage;
4. cite the advantages and disadvantages of modified
atmosphere storage; and
5. Define modified humidity packaging.

3. LESSON OUTLINE
1. Definition of Modified Atmosphere and Modified
Atmosphere Packaging
2. Commercial Uses of Modified Storage Packaging
3. Principles of Modified Atmosphere Storage
4. Advantages and Disadvantages of Modified Atmosphere
Storage;
5. Definition of Modified Humidity Packaging

4. DEFINITION
• Modified atmosphere is a condition of atmosphere
(normally in a package of commodity) around the
commodity that is different from that of air (78.08%
N2, 20.95% O2, and 0.03% CO2).
• Usually this involves reduction of O2 and/or
elevation of CO2 concentrations.

5. • Modified atmosphere packaging (MAP)
involves the exposure of produce to the
atmosphere generated in a package by the
interaction of produce, the package and the
external atmosphere.

6. .
• Different additives that may affect the atmosphere may be
introduced into the package before it is sealed.
• The main feature distinguishing MAP from controlled atmosphere
(CA) is that , in the case of MAP, active human involvement stops at
the moment of sealing.
• Wide spectrum of techniques of MAP from Individual sealed
packaging to the more intricate control of microorganisms in the new
package of salad bar items.
• MAP is a multidisciplinary technology of maintaining freshness that
utilizes basic principles of chemistry, physics, plant physiology and
pathology, microbiology, food science, engineering, polymer
chemistry.

7. Presentation 3.2
Modified and controlled atmosphere storage

8. • Modify the concentration
of gases in the produce
packing.
• Reduce respiration rate.
• Reduce ethylene action.
• Delay ripening &
senescence.
• Increase product’s shelf
life.
O2
CO2
O2 CO2
21% O2 0.035% CO2

9. 21% Oxygen
0.35% CO2
2% O2
1% CO2
Filters
Cold room
0ºC
Fruit, as any living entities..breathe

10. Presentation 3.2
• CA is used for transporting and storage of apples, pears,
less used in kiwifruits, avocados, nuts, dry fruits and
persimmon.
• MA- for long distance transport is used in mangoes,
apples, bananas, avocados, plums ,strawberries,
blackberries, peaches, figs, nectarines.

11. PRINCIPLES OF MAP
• MAP is a dynamic system during which respiration
and permeation occur simultaneously.
• Factor affecting both respiration and permeation
must be considered when designing a package.
• Commodity mass, temperature, O2, CO2, and C2H4
partial pressure and stage of maturity are known to
influence respiration in a package.

12. PRINCIPLES OF MAP
• Type, thickness, intended
holes, and surface area of
packaging film, as well as
temperature, RH, and
gradient of O2 and CO2
partial pressures across
the film, are known
determinant of permeation.

13. PRINCIPLES OF MAP
• Package equilibrium or
steady state is defined
as the point at which
the commodity CO2
production and O2
consumption rates are
equal to the permeation
rates of the respective
gases through a
package at a given
temperature.

14. PRINCIPLES OF MAP
• Poorly designed
package will become
anaerobic or develop
unacceptable levels of
CO2 before equilibrium
is achieved.

15. CO2
O2
Gasconcentration(O2
andCO2)
0.03%
21%
Time

16. • Retardation of senescence
• Reduction of fruit sensitivity to
ethylene action
• Alleviation of certain physiological
disorders
• Directly and indirectly affect
postharvest pathogens
• Useful tool for insect control in
some commodities
Potential benefits
Kader et al. (2002)

17. Potential harmful effects
• Initiation or aggravation of certain
physiological disorders
• Irregular ripening of fruits
• Off-flavor and off-odors
• Susceptibility to decay may
increase
• Sprouting and retardation of
periderm development are
stimulated in some root and
tuber vegetables, such as
potatoes.
Kader et al. (2002)

18. • Reduction of weight loss, desiccation and shriveling
• Delay of ripening
• Alleviation of chilling injury
• Semicentralised manufacturing option
• Expanded radius of distribution system
• Reduction of labor and waste at the retailer level
• Quality advantages such as colour, moisture,
flavour and maturity retention
• Excellent branding option
• Reduction of handling and distribution of unwanted
or low grade produce
• Quality advantages transferred to the consumer
Ben-Yehoshua et al.
(1993)
Advantages

19. • Requirement of additional investment in
machinery and labor in the package line
• Risk of spoiled produce due to improper
packaging of temperature abuse
• Possible occurrence of new risk of
microbiological safety due to possible
development of anaerobic pathogenis
flora
• Plastic film may be environmentally
undesirable unless effective recling is
installed
• MAP technology is still unavailable for
most produce
Disadvantages
Ben-Yehoshua et al.
(1993)

20. MAP for fruits and vegetables
• Various films have been used
for packaging F&V to minimize
respiratory anaerobiosis and
potential microbiological
hazards
• In China and Japan sealed-
packaging has become a
common new technique for
citrus fruit storage.
• Sealed-package of many F&V
are commonly available on the
shelves of supermarket.
• One of the novel approaches
in MAP of F&V is the
introduction of a gas mixture of
desirable composition into a
package before sealing.

22. RH in a plastic package is usually
very high.
Reduction in RH to an optimal
amount may be critical for the
success of MAP Research: CaCl2,
Sorbitol, NaCl, xylitol and KCl
sealed with one mature tomato
fruit at 20C in simulated package
for 48 days resulted in stable RH
of 35, 75, 75, 80 and 85%,
respectively.
Modified humidity packaging

23. RH is a function of the
ratio of chemical and
fruit mass.
The storage life of
package red-type
tomato fruit at 20C
was extended from 5
days using no pouch
to 15-17 days with a
pouch containing
NaCl.
Modified humidity packaging

25. Thank You!