Components of Edible Packaging

1.Polysaccharides 

 Polysaccharides are natural polymers produce by plants which are found in all types of organisms and plants. It contain cellulose, chitosan, pectin, agar, carrageenan etc.,

   Cellulose  has strong hydrogen bonding property and are water insoluble, so used to form water soluble films. 

 Chitosan has antifungal behaviour to fungi, hence it’s an acute choice in making of preservative coating for fresh fruits and vegetables. Chitosan films are clear, tough and flexible with good resistance to oxygen, fat and oil, but are sensitive to moisture.

     Pectin and its derivatives based edible films are fragile and elastic with less elongations.

     Agar present in red algae as a gel which is insoluble in cold water and soluble in hot water, hence specifically it used as a gel inducer in candy and desserts.

2.Protein

      Protein based edible films can be made from both animal or plant protein sources. It has more shelf life compared to polysaccharide-based edible films, due to less moisture sensitive. 

   Gelatine is used as encapsulation of low moisture food ingredients, coatings on meats and pharmaceuticals to protect against oxygen and light, moisture etc. 

 Collagen is an animal protein which shows a thermoplastic behaviour and provides extended hydrogen bonding in parallel structures to form into a fibre edible film which is widely used in sausage making.

  Soy protein films are generally produced from soy protein isolate, which are flexible, clear and smooth compared to films formed by other plant protein sources , and are excellent gas barriers compared to lipids and polysaccharides. 

 Milk proteins contains casein protein and whey protein. Casein based films remains stable for a range of pH, salt concentrations and temperature, which form transparent, flavourless and flexible films. 

3.Lipids

  The most effective lipid substances are paraffin wax and beeswax, but due to lipids structural restrictions lipid based films are not been well explored.

        As per the research of Saucedo-Pompa et al. (2007), an edible coating with candelilla wax and Aloe vera gel, applied on fresh-cut fruits. They concluded that candelilla coatings were an alternate for the preservation of foods, also helpful in firmness, weight loss, and appearance. 

   Paraffin wax is estimated by distillate fraction of crude petroleum and contain a mixture of solid hydrocarbon which is obtained from ethylene catalytic polymerization. It is permitted for use on raw fruit and vegetable and cheese (Bourtoom, T. 2008).

   Shellac resins are a secreted by the insect Laccifer lacca and is composed of a complex mixture of aliphatic alicyclic hydroxyl acid polymers. It is mostly used in coatings for the pharmaceutical industry and but few studies have been reported on foods too (Hernandez, 1994).

References

1. Bourtoom, T., Edible films and coatings: characteristics and properties, International Food Research Journal 15(3): 237-248 (2008).
2. Hernandez, E. 1994. Edible coating from lipids and resins. In Krochta, J. M., Balwin, E. A. and Niperos-Carriedo, M. O. (Eds.). Edible Coatings and Films to Improve Food Quality, p. 279-303. Lancaster. Basel: Technomic Publishing.
3. Renge Sachin M and B.B Renge., Concept of Edible Packaging, Agriculture Observer an online magazine, Vol:1, Issue :3 Article No. :31 August 2020.
4. Saucedo-Pompa, S., et al., 2007. Effect of candelilla wax with natural antioxidants on the shelf life quality of fresh-cut fruits. J. Food Qual. 30, 823–836.