Edible films represent a novel approach in the food industry, offering an innovative solution for preservation and packaging. These thin, consumable layers are applied directly to food products, creating a protective barrier. This technology aims to enhance food quality and safety while addressing environmental concerns associated with traditional packaging materials.
What Are Edible Films?
Edible films are defined as thin, continuous layers made from food-grade materials that can be safely consumed along with the product they enclose, or easily removed. These layers typically have a thickness less than 0.3 millimeters, forming a flexible and often transparent covering. They are distinct from traditional non-edible packaging because their composition allows for ingestion, eliminating the need for disposal.
The materials used to create these films are derived from natural, renewable sources, making them inherently biodegradable. Unlike conventional plastics, edible films decompose naturally, reducing environmental pollution. This characteristic makes them an attractive alternative in a world increasingly focused on sustainable practices. They can be applied as freestanding sheets or directly as coatings on food surfaces, providing a versatile packaging format.
How Edible Films Work and Their Advantages
Edible films create a controlled microenvironment around food products, slowing spoilage. They act as selective barriers, regulating the transfer of gases like oxygen and carbon dioxide, as well as moisture and volatile flavor compounds. For example, limiting oxygen exposure prevents oxidative rancidity in fats and oils, preserving freshness. Controlling moisture exchange reduces dehydration or unwanted moisture absorption, maintaining texture and weight.
Beyond passive barrier functions, these films can carry and release active compounds directly onto the food surface. This includes antimicrobials, which inhibit the growth of spoilage-causing bacteria and fungi, and antioxidants, which prevent undesirable chemical reactions that degrade food quality. The localized delivery of these agents provides targeted protection, potentially reducing the overall amount of preservatives needed.
Edible films offer several advantages. They extend the shelf life of various food products by mitigating spoilage factors, which reduces food waste. By maintaining nutritional value and sensory attributes like color, flavor, and texture, they enhance the overall quality of food for consumers.
Composition and Practical Applications
Edible films are formulated from biopolymers, which fall into three main categories: polysaccharides, proteins, and lipids. These can also be combined to form composites. Polysaccharides, such as starch, cellulose, pectin, and alginates, are used for their film-forming abilities and as barriers to gases like oxygen. Their hydrophilic nature often means they are combined with other materials to improve water resistance.
Proteins, including gelatin, casein, and soy protein, also form robust films and serve as good oxygen barriers. Lipids, such as waxes (e.g., carnauba, beeswax) and fatty acids, are incorporated to provide a barrier against moisture loss due to their hydrophobic properties. Combining these materials in composite films allows for tailored properties, leveraging the strengths of each component.
Practical applications of edible films are widespread in the food industry. They are applied as coatings on fresh fruits and vegetables to reduce moisture loss and control respiration rates, delaying ripening and maintaining firmness. For example, a wax emulsion can be applied to apples to improve gloss and prevent softening. They can also coat nuts, preventing oil migration and rancidity.
Beyond fresh produce, edible films find use in processed foods for portion control, such as separating layers in multi-component items, or for packaging individual snacks and candies. Some films are designed as edible wrappers for confectionery or as alternatives to traditional bread or tortillas. The ability to incorporate flavors, colors, or nutraceuticals directly into the film broadens their utility, delivering an enhanced sensory experience or added nutritional benefits with the food.