114 Recent Patents on Food, Nutrition & Agriculture, 2012, 4, 114-122
1876-1429/12 $100.00+.00 © 2012 Bentham Science Publishers
Edible Coatings Enriched with Essential Oils and their Compounds for
Fresh and Fresh-cut Fruit
Maria D. Antunes
a
, Custódia M. Gago
a
, Ana M. Cavaco
b
and Maria G. Miguel
a,
*
a
Faculdade de Ciências e Tecnologia, Universidade do Algarve, IBB-Centro de Biotecnologia Vegetal, Ed. 8, Campus
de Gambelas, 8005-139 Faro, Portugal;
b
Faculdade de Ciências e Tecnologia, Universidade do Algarve, Centro de
Electrónica, Optoelectrónica e Telecomunicações, Ed. 2, Campus de Gambelas, 8005-139 Faro, Portugal
Received: February 20, 2012; Revised: March 29, 2012; Accepted: May 12, 2012
Abstract: Fresh fruit and vegetables consumption has increased in the past few years due to the enhanced awareness of
consumers for healthy food. However, these products are highly perishable, and losses can be of great significance if
postharvest correct management is not provided. Fresh-cut products are of increasing importance, since they are presented
to the consumer in a state that allows for direct and immediate consumption. However, those products are even more per-
ishable since cutting can induce a series of senescence associated responses to wounding, and are more susceptible to mi-
crobial spoilage. Edible coatings, which intend to reduce ripening processes and protect the fruit from water loss and
spoilage may be a good way to enhance the shelf life of these products. More recently, the inclusion of additives into these
edible coatings to increase their effectiveness, such as essential oils and their constituents with antimicrobial and antioxi-
dant activities, has been reported and patented.
Keywords: Edible coating, essential oils, film coating, fresh-cut, fruit, vegetables.
INTRODUCTION
The consumption of fruit and vegetables is widely ac-
cepted as health beneficial, and the market for fresh ready to
eat produce is increasing markedly due to dramatic changes
in the consumer life style [1, 2]. Fresh-cut products are fruit
or vegetables presented to the consumer in a state that allows
for direct and immediate consumption, without the need for
previous preparation or transformation. It is more difficult to
maintain the fresh-like quality and nutritional value through-
out shelf life of these products compared with entire fruits
and vegetables. In fact, wounded tissue responds with a rise
in respiration rate and ethylene production, inducing ripening
and rapid senescence [3]. Hence, it is of paramount impor-
tance to determine the best way to preserve minimally proc-
essed fruits, considering that all the previously mentioned
factors promote quality loss. Several studies have been con-
ducted regarding the preservation of these products and their
respective quality. For better preservation of fresh-cut com-
modities, investigations are towards the use of preservatives
such as anti-browning and/or firming agents [1, 4].
Low storage temperature and modified storage packaging
(MAP) are used to extend the shelf life of many whole and
fresh-cut fruit and vegetable products, as they reduce the
respiration rate, surface damage and browning [5]. More
recently, it has been reported that film coating can extend
shelf life in fresh-cut produce [6, 7]. Edible coatings have
been used widely in whole fruits to reduce water loss and
preserve quality [3]. For example, lipid-based edible
*Address correspondence to this author at the Faculdade de Ciências e Tec-
nologia, Universidade do Algarve, IBB-Centro de Biotecnologia Vegetal,
Edif. 8, Campus de Gabelas, 8005-139 Faro, Portugal; Tel: +351289800900;
Fax: +351289818419; E-mail: mgmiguel@ualg.pt
coatings are excellent for preventing dehydration, and add
brightness to the epidermis. Edible coating can also include
some additives such as antimicrobials. These can effectively
protect fresh-cut fruit against bacterial contamination by
retaining preservatives on the surface of the cut fruit where
they are needed, avoiding diffusion into the tissue [8].
Recent exploitation of natural products to control decay
and extend storage life of perishables has received more and
more attention. Essential oils are natural compounds isolated
from aromatic plants. Some of these oils are generally rec-
ognized as safe (GRAS) for environment and human health.
In this way, the interest in the use of such oils for a sustain-
able agriculture has increased and a lot of research has been
done, proving for many cases, that plant essential oils and
extracts may play the role as pharmaceuticals and food pre-
servatives [9-11]. Studies on the use of essential oils and
their constituents against microbial pathogens present in hor-
ticultural commodities have provided a set of results that can
lead to effective options in what concerns food safety [11].
Due to the antimicrobial effect of essential oils and their
components, their incorporation into edible coatings shows a
great potential to increase shelf life and improve quality of
fresh and fresh-cut fruits.
To our knowledge, very few patents have been made
concerning the use of essential oils and their components
incorporated into edible coatings to ensure quality and safety
of fresh and fresh-cut horticultural produce extending shelf
life. We intend to make a review on what is published about
edible coatings, including patents from 2010, used to pre-
serve shelf life of fresh horticultural products.