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39 Minimally Processed Foods 757etc. Barbosa-Canovas et al. (1998) suggested that the applica-
bility of multitarget preservation approach is not only limited
to traditional methods of food preservation, but also valid for
emerging nonthermal technologies like HPP, PEF, etc. A lot of
new research is being done using newer technologies, which are
based upon the central idea of multitarget preservation.Limitations of Hurdle ConceptCombination of two or more hurdles results in either additive,
synergistic, or antagonistic effect. Addition and synergism jus-
tify the use of hurdle technology but some studies have shown the
negative effect of using some hurdle combinations (Jordan et al.
1999, Casey and Condon 2002). The antagonistic phenomenon
is related to the type of conditions, intensity of preservative
action of each hurdle, and the type and nature of food to be
minimally processed.PACKAGING TECHNIQUES FOR
MINMALLY PROCESSED FOODSMapMAP is a method of preserving the fruits and vegetables by
changing the composition of the air surrounding the food in
a package. Different gas mixtures in varying concentrations are
used in modifying the atmosphere inside the package. Generally,
oxygen and carbon dioxide are used for packaging of minimally
processed fruits and vegetables, but the potentials of other gases
like nitrogen, carbon monoxide, and noble gases (Helium, Ar-
gon, and Neon) have also been realized (Sandhya 2010). Higher
carbon dioxide and reduced oxygen levels have been found ef-
ficient in enhancing the shelf life and preventing the problem of
enzymatic browning in fruits and vegetables. Generally, 15–20%
CO 2 has been considered effective in preventing decay in fresh
fruits and vegetables. In case of meat products, oxygen is used
for retaining the red color of oxymyoglobin, but oxygen levels
are reduced in other products to prevent oxidative rancidity and
spoilage due to microbes. Very low oxygen or high concentra-
tion of carbon dioxide can initiate anaerobic respiration in the
package, which may lead to formation of certain undesirable
metabolites, harming the product’s physiology (Soliva-Fortuny
and Martin-Belloso 2003).
The essential characteristics for MAP packaging material
are the gas permeability and water vapor transmission rate.
Most common packaging materials include polyvinyl chloride,
polypropylene, polyethylene, and polyethylene terephthalate
(Mangaraj and Goswami 2009). These days, laminates or coex-
truded films are used for packaging. The traditional gas mixture
configuration is not enough to prevent the deteriorative reaction
if fruits and vegetables get wounded. Minimal processing up
to some extent is responsible for initiating the tissue damag-
ing. Also, the packaging materials used for MAP are prone to
some limitations pertaining to textural, color, and permeability
changes. Hence, as a solution, edible coatings are being seen
as potential alternative to the MAP technique (Rojas-Grau et al.
2009). The advantages of edible coating are numerous, and con-stantly improvements are being made by incorporating active in-
gredients like antioxidant, antimicrobials, antibrowning agents,
etc. Edible coatings have been explained later in the chapter.Active and Edible PackagingActive packaging implies incorporation of certain additives that
can enhance the shelf life, flavor, texture, etc. by interacting
with the food product inside the package. These additives can
be oxygen scavengers, carbon dioxide absorbers or generators,
ethanol emitters, ethylene absorbers, and moisture absorbers
(Ohlsson and Bengtsson 2002). Antioxidants and antimicrobial
compounds are also used in the active packaging.
Inclusion of chemical or physical additives in packages may
become a hindrance for consumer acceptance of packaged foods.
The development of packaging techniques that use natural mate-
rials like edible coating is a potential alternative to the chemical-
based packaging methods. Edible coating is applied on the sur-
face of food by spraying, dipping, or brushing. Sources of edible
coatings are polysaccharides, proteins, and lipids (Lin and Zhao
2007). Edible coatings help reduce water loss and delay ageing
by allowing controlled and selective gas permeability through
product. They are also environmentally friendly as they reduce
synthetic packaging waste.CONCLUSION
Minimally processed foods have become very popular with con-
sumers. All the aspects related to minimally processed food,
from processing to packaging, are witnessing an unprecedented
continuous improvement. The combined treatment methods us-
ing thermal and nonthermal technologies have shown promising
results. Updated knowledge of the different emerging techniques
and how they might interact when combined may be critical in
developing new and innovative processing strategies.REFERENCES
Abadias M et al. 2008. Efficacy of neutral electrolyzed water (NEW)
for reducing microbial contamination on minimally processed
vegetables.Int J Food Microbiol123(1–2): 151–158.
Aguilo-Aguayo I et al. 2008. Influence of high-intensity pulsed
electric field processing on lipoxygenase andβ-glucosidase ac-
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Aguilo-Aguayo I et al. 2009a. Changes in quality attributes through-
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Aguilo-Aguayo I et al. 2009b. Avoiding non-enzymatic browning
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