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Israel Agriculture 2014

Layer-by-Layer Edible

Coatings to Improve Quality

and to Prolong Shelf Life of Dr. Elena Poverenov
Department of Food Quality and
Safety, Agricultural Research
Organization, The Volcani Center,
Fresh Agricultural Products Bet-Dagan, 50250, Israel.

Figure 1. Schematic representation of the agricultural products coated Figure 2. Fresh cut melons coated by: Layer-by-Layer alginate-
by Layer-by-Layer edible coatings. chitosan coating, chitosan coating, alginate coating and non-coated
afer 10 days of storage at 7 C.
o

Edible coatings are a new promising approach for controlling have to answer a long list of various requirements. The
the quality and extending the shelf-life of fresh agricultural necessary requirements include (1) good adhesion to a food
products (Baldwin et al., 2011). Edible coatings may control surface, (2) normal gas permeability and (3) an acceptable
moisture transfer protecting products from deterioration and color, taste, favor and texture. In addition to be valuable
improving textural quality, help to retain volatile components, edible coatings are expected (4) to improve appearance and
reduce the internal oxygen partial pressure decreasing a mechanical properties of agricultural products, (5) to retard
metabolism of fresh products (Falguera V et al., 2011). moisture migration, (6) to protect agricultural products from
Moreover, active edible coatings may have antimicrobial, physiological and/or microbiological damages. Single coating
material is ofen unable to satisfy all these requirements.
antioxidant, antibrowning and texture enhancing properties Therefore, Layer-by-Layer (LbL) approach could be very
(Rojas-Grau et. al., 2009). Edible coatings are based on helpful. Layer-by-Layer method is based on the alternate
completely biodegradable and biocompatible polymers deposition of various polymers to produce ultrathin layers
from natural sources such as polysaccharides, proteins, on surface. Physicochemical properties of the created flms
and lipids (Vargas et al., 2008) therefore they respond to can be controlled by changing the deposition conditions and
consumer demand for more natural and environmentally by altering the nature of polymers themselves. The technique
friendly approaches of product quality control. Due to all has applications range from optical devices to biomaterials.
the mentioned benefts edible coatings attract much current Despite LbL approach has great potential to control properties
scientifc and practical interest worldwide. and functionality of edible coatings until recently it was almost
To be applicable on fresh agricultural products, edible coatings unexplored in the feld of food quality and shelf life extending.
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