that produce modified atmospheres, minimizing respiration rates,
reducing moisture exchange, delaying deterioration, controlling
microbial growth, and carrying functional ingredients (antioxidants,
antimicrobials, and so on). ECs can be elaborated with
polymers such as proteins, lipids, and polysaccharides including
pectin, chitosan, and pullulan (Costa and others 2010).
Pectin, consisting of 1,4-linked α-D-galacturonic acid, is a complex
anionic polysaccharide present in the cell wall of many fruits
and vegetables (Iijima and others 2000). Additionally, chitosan, β-
(1→4)-2-amino-2-deoxi-D-glucosa or D-glucosamine, is a natural
polymer derived by deacetylation of chitin, which is a major
component of crustacean shells (crabs, shrimps, and crawfish). This
compound, which has been used to elaborate ECs, is a cationic
polysaccharide that exhibits bactericide and fungicide activities
(Campos and others 2011; Dutta and others 2009). Finally, pullulan
is an extracellular linear homopolysaccharide that is formed
by maltotriose and maltotetraose units having both α-(1→6) and
α-(1→4) linkages. Produced by Aerobasidium pulluans, pullulan
is capable of forming edible films and coatings. However, this
polymer has not yet been thoroughly explored as a coating or
packaging material (Diab and others 2001; Kandemir and others
2005; Eroglu and others 2014).
In most fresh or processed products, microbial contamination is
found mainly on the surface. Therefore, EC based polysaccharides
are applied and formed directly on the surface of food products
and can be added with a paintbrush or by spraying, dipping, or
fluidizing (Mchugh 2000; Sorrentino and others 2007; El-Anany
and others 2009; Falguera and others 2011). Moreover, active
ingredients, such as antimicrobials or bioactive compounds (essential
oils), can be incorporated into ECs to form edible active coatings (EACs) to more efficiently protect food surfaces and increase
product quality and shelf life (Sorrentino and others 2007;
Rojas-Grau and others 2009; Costa and others 2010; Falguera ¨
and others 2011; Vu and others 2011). In most fresh or processed
products, microbial contamination is found mainly on the surface.
Therefore, EC based polysaccharides are applied and formed directly
on the surface of food products and can be added with a
paintbrush or by spraying, dipping, or fluidizing (Mchugh 2000;
Sorrentino and others 2007; El-Anany and others 2009; Falguera
and others 2011). Moreover, active ingredients, such as antimicrobials
or bioactive compounds (essential oils), can be incorporated
into ECs to form EACs to more efficiently protect food surfaces
and increase product quality and shelf life (Sorrentino and
others 2007; Rojas-Grau and others 2009; Costa and others 2010; ¨
Falguera and others 2011; Vu and others 2011). According to
the European Regulations, ECs supporting antimicrobials can be
considered as active materials. EACs are intended to extend the
shelf life or to maintain or improve the condition of packaged
food. These materials should not endanger human health, bring
about an unacceptable change in the composition of the food
and not bring about deterioration in the sensorial characteristics.
Also, the active and intelligent materials and articles should be adequately
labeled to indicate that the materials or articles are active
and/or intelligent (Regulations (EC) No 1935/2004 and (EC)
No 450/2009). According to U.S.A. regulations, ECs must comply
with the Code of Federal Regulations (21CFR172), and be
declared on the label under the Federal Food, Drug, and Cosmetic
Act (FD&C) (FDA 2006; Campos and others 2011).
Antimicrobials, such as potassium sorbate (controls molds
growth) and sodium benzoate (controls yeasts, bacteria, and some
molds), are not toxic for human beings and are ideal preservatives
for acidic foods (Garcia and others 1998). Several studies of ECs
incorporated with antimicrobials such as potassium sorbate have
been performed. Park and others (2005) elaborated ECs based on
chitosan with potassium sorbate. However, the study only determined
the effects of the coating on the growth of Rhizopus sp.
and Cladosporium sp. Unfortunately, significant inhibitory effects
of chitosan and potassium sorbate on fungal growth on fresh strawberries
were not detected. Other studies have used starch-based
coatings incorporated with antimicrobials such as potassium sorbate
and citric acid (Garcia and others 1998; Garcia and others
2001; Costa and others 2010). However, is important to note that
the effect of coatings based on polysaccharides, such as pectin, pullulan,
and chitosan with sodium benzoate and potassium sorbate,
have not been studied in strawberries. Therefore, the objective of
this study was to determine the effects of EACs based on pectin,
pullulan, and chitosan with sodium benzoate and potassium sorbate
on the quality and shelf life of cv. Albion strawberries.