5 - Starch-based edible films

Abstract

Commercially important starch is obtained from corn, wheat, rice, potatoes, tapioca, and peas. Starch is a polysaccharide that is produced in almost all plants by photosynthesis. Naturally occurring starch is present in the form of semi-crystalline granules, which vary in shape, granule size, size distribution, association, and chemical composition. Starch consists of two components: amylose and amylopectin. Edible or biodegradable packagings made from various biological resources and their applications have recently been investigated. Cellulose ethers have been used as ingredients in coatings for fruits, vegetables, meats, nuts, confectionery, bakery, grains, and other agricultural products. Dehydration and growth of microbial organisms in food products have been delayed by using edible and biodegradable films and coatings. Moreover, the flavor, odor and overall organoletic characteristics were not modified. Many materials from biological resources have been used for edible or biodegradable film and coating formulations, such as polysaccharides, proteins, lipids or their mixtures. The properties of edible films depend on the type of film-forming materials and especially on their structural cohesion. Additives—such as plasticizers, cross-linking agents, anti-microbial agents, anti-oxidants, and texture agents—are used to alter the functional properties of the films. Among the natural polymers, starch has been considered as one of the most promising candidates for future materials because of the attractive combination of price, availability and thermoplasticity.