The application of petroleum polymers and plastics in food packaging is exhibiting an increasing trend, due to low price and desirable characteristics. Nevertheless, these polymers are nonbiodegradable, nonrenewable, and require landfills. Edible polymers are suitable alternative for synthetic polymers, which can be consumed by animals or human beings without health risk. Edible packaging can protect the foodstuff from microbial and chemical deterioration during storage and distribution, which can lead to extend the quality and safety of packaged food. The plant gums as natural polymers are able to form films and coatings with good barrier properties against the transfer of gases such as oxygen, carbon dioxide, and moisture. This review summarized the production and characteristics of novel edible films and coatings based on plant gums such as tree exudate, seed, and tubers.
K E Y W O R D Sedible films and coating, physico-mechanical properties, seed gum, tree exudates, tubers gums
| INTRODUCTIONOver recent decades, the increasing application of synthetic polymers for food packaging caused some health and environmental concerns. 1 Polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP), polystyrene (PS), and polyvinyl chloride (PVC) are plastics used widely in food packaging due to their low cost, excellent resistance, and superior water barrier and protective features. Nevertheless, plastics are nondegradable and some of them are not recyclable and cause environmental consequences. To overcome these obstacles, the convincing solution is the application of biodegradable polymers. 2 Biodegradable polymers are substances that decompose into water, carbon dioxide, methane, mineral compounds, and biomass in nature. 3 Some of the polymers including polycaprolactone (PCL), polyglycolide (PGA), and polybutylene succinate adipate (PBSA) are biodegradable, but they are synthetic and produced from fossil sourced chemicals that are nonrenewable. 2 Biopolymers, promising alternatives for synthetic polymers, are classified into three groups according to their sources including biopolymers derived from biomass (eg, polysaccharides, proteins, and lipids), biopolymers synthesized from bio-derived monomers (eg, polylactic acid), and biopolymers provided by microorganisms (eg, gellan and pullulan). 3 The new approach in food packaging is the application of films and edible coatings based on biopolymers to extend the shelf-life and maintain food quality. 1,4 The edible coating is a thin layer of biopolymers applied directly in liquid form on the surface of foods by immersing or spraying method, whereas a film is prepared separately as a solid sheet, then applied as a wrapping on or between food products, as illustrated in Figure 1. 5,6 Films and coatings have been used to prevent dehydration and add shin to fruits and vegetables since the 20th century. In addition to their selective gas and moisture barrier properties, they can act as a carrier of coloration, flavoring, sweetener, antimicrobial, and antioxidant agen...
