2. INTRODUCTION
• Vegetables and fruits are highly perishable as they contain 80 – 90 percent water
by weight. If they are left without cuticle, the water quickly begins to evaporate, resulting
in poor product shelf life. Major losses in quality and quantity of fresh fruits and
vegetables occur between harvest and consumption. Edible coatings on fresh fruits and
vegetables can provide an alternative to modified atmospheric storage by reducing quality
changes and quantity losses through modification and control of internal atmosphere of
the individual fruit and vegetable. Edible coatings may contribute to extend shelf life of
fresh fruits and vegetables by reducing moisture and solute migration, gas exchange,
respiration and oxidative reaction rate as well as by reducing or even suppressing
physiological disorders. The most suitable, abundant, renewable and low cost material for
producing edible coatings based on biopolymers is starch.
3. EDIBLE COATINGS
• Consumers demand higher quality and longer shelf life foods, while reducing disposal packaging
materials and increasing recyclability. Such demands have caused increased interest in edible and
biodegradable films or materials which serve as mass transfer barriers to moisture, oxygen, carbon
dioxide, lipids, flavor and aroma between the food component and surrounding atmosphere and
improve quality of almost any food system. Edible film is defined as a thin layer of material which
can be eaten as a part of whole product. However, some of the drawbacks of biopolymers as a food
packaging materials compared to non biodegradable materials include poor mechanical properties,
high hygroscopic capacity, rigidity, brittle character, and barrier properties. To overcome these
limitations, starch is blended with other polysaccharides and plasticizers which resulted in good film
forming ability.
4. GENERAL CHARACTERISTICS OF EDIBLE FILMS
• Not contain any toxic, allergic or non-digestible components;
• Provide structural stability to prevent mechanical damage during transportation, handling, and display;
• Have good adhesion to surface of food to protect and to provide uniform coverage;
• Have a control water migration both in and out to protect food and maintain the desired moisture content;
• Provide semi-permeability to maintain internal equilibrium of gases involved in aerobic and anaerobic
respiration, thus retarding senescence;
• Prevent loss or degradation of components that stabilize aroma, flavor, nutritional and
organoleptic characteristics, which are necessary for consumer acceptance;
• Provide biochemical and microbial surface stability while protecting against contamination;
• Maintain or enhance aesthetics and sensory attributes (appearance, taste etc.) of product;
• Be able to serve as carrier for desirable additives such as flavor, fragrance, coloring, nutrients, vitamins,
antioxidants and antimicrobial agents, and
• Be easily manufactured and economically viable.
5. STARCH
• Starch is the main carbohydrate which is stored as a food material in plants. It contains two types
of glycose units, amylose and amylopectin. Both have α (1→4) linkage between the polymers in
short or long chains. Amylose has a linear chain, while amylopectin can have branches due to
α(1→6) linkage. Starch is found in the form of semi-crystalline hydrophilic granules. Starch is
known for being biocompatible, biodegradable, nontoxic and for having low cost. This material is
relatively easy to handle. Besides being totally biodegradable, is also widely available in nature from
sources such as cereals, roots, tubers and palms. Several authors studied the development of starch
films from different sources, which ones found good barrier results in their work on the development
of green peas starch films; and quinoa starch films. Which says that these films could be applied on
food products to improve their preservation, distribution and marketing. Starch is recently receiving
more attention as a material to be used as packaging.
6. CASSAVA STARCH
• Cassava starch is easily produced with low cost, hence become a cheap source for edible film.
However, edible film from cassava starch has low quality due to its low strength and high water
vapor transmission rate. Cassava starch or tapioca is one of cheapest edible film’s raw materials.
Cassava starch consists of amylase and amylopectin which containing linear polymer with a
molecular weight of about 10 and a highly branched polymer with high molecular weight. The main
component for film formation from cassava is the polymerization is amylose. However, the
cassava starch film brittle and weak leading to inadequate mechanical properties.
7. RICE STARCH
• Rice (Oryza sativa L.) is one of the most popular cereals in the world, especially in Asian
countries. The popularity of this cereal is due to its many characteristics, such as nutritional quality,
practicability and applicability. Rice is a major source of energy owing to the high concentration of
starch, proteins, minerals, and B vitamins. It is the staple food of more than half of the world
population, and increasingly popular for its beneficial health properties. In recent years, the interest
in rice starch has increased because of its specific characteristics: white color, odorless, easily
digestible, hypoallergenic, and small granular form. These characteristics allow multiple applications
of starch, both in food and in non-food industries.
8. CORN STARCH
• One technique that can maintain fruit quality and extend shelf life, one of which is a coating
technique called edible coating. The edible coating is a thin layer used to coat products to protect and
maintain the quality of the coated products against product deterioration. Corn starch is
polysaccharide widely used for packaging material (edible coating) on agricultural products because
of its low price and accessibility. Corn starch has a characteristic of white color, resulting in an
(edible) layer of which will be more transparent along with the addition of corn starch. The stability
of edible coatings can be increased by adding antioxidants and antibacterial substances to maintain
the quality of fruits and vegetables.
9. MAKING OF EDIBLE FILM FROM VARIOUS
SOURCES
• Chitosan
• Xanthum gum
• Fibers
• Lipids
• proteins
10. CONCLUSION
Starch as a packaging material is socially responsible, economically viable, and is suggested as an
important tool to overcome existing challenges that are associated with packaging material and
consequently resulting in enhanced shelf life, quality, safety, and security of foods. The starch film
showed excellent forming properties like air, moisture, barrier, heat-sealing capacity, etc.
However, further research focused on a commercial scale needs to be done so that more realistic
information can be used to commercialize edible coated fresh fruits and vegetables
