Imagine baking a pizza in the oven without removing the package. The film that involves the pizza is made of tomato and, when heated, will be incorporated to the pizza and becomes part of the meal. This material already exists and was developed by researchers at Embrapa Instrumentation (SP) which made edible films of different foods such as spinach, papaya, guava, tomato and many others that can be used as raw material. The research was developed under the Nanotechnology Applied to Agribusiness Network project (AgroNano) and received investments of R$ 200 thousand. "We can use food industry waste to process the material and this ensures two sustainability characteristics: the use of food waste and the substitution of a synthetic packaging that would be discarded", says the researcher Luiz Henrique Capparelli Mattoso, head of Embrapa Instrumentation and research coordinator. He also points out that developing films from tropical fruits is a pioneer work in the world. The material has physical characteristics similar to conventional plastic, such as resistance and texture, as well as equal capacity of protecting food. However, the fact that it can be ingested opens a vast field to be explored by the packaging industry. There are wrapped poultry in bags containing seasoning in its composition, sachets of soups that can dissolve with their contents in boiling water and many other possibilities. The difference lies in the raw material. The edible plastic is made primarily of dehydrated food mixed with a nanomaterial to bind the whole. "The biggest challenge of this research was finding the optimal formulation, recipe ingredients and proportions so that the material acquired the features that we needed to," says material engineer José Manoel Marconcini, Embrapa researcher who carried out this work. He explains that the foods used as raw material pass through the lyophilization process. This is a type of dehydration in which, after the food freezes, any water contained therein is transformed directly from solid to gas without passing through the liquid phase. The result is a completely dehydrated food with the advantage of maintaining its nutritional properties. It can be applied to many different foods like fruits, vegetables and even some types of spices, which explain the great diversity of edible raw materials and print the flavor and color of the packaging. Mattoso believes the edible plastic can also help reduce other problem: food waste. In addition to waste in working condition not used by food industry, there are many plants which stop being marketed due to the visual aspect even being in consumer conditions. "These vegetables that would spoil on the shelf can be raw material for edible packaging", says the specialist who is already thinking of partnerships with companies in the field to develop as a commercial product the results obtained in laboratory. According to him, the new packaging may also receive raw material of a booming market, the ready to eat meals. Mattoso adds that this is a branch which produces a lot of waste as peels and small pieces. He gives as an example the called baby carrots that are carved into small pieces of carrot. For the specialist, the remains of this process could become raw material for a plastic bag to the legume. A 20-year-old-work The material development was a result of two decades of work when the studies in materials at Embrapa Instrumentation began. "At first, the concern was to use renewable materials looking for alternatives to synthetic petroleum polymers", reminds Mattoso. For this purpose the group started to add natural fibers to synthetic plastics resulting in composites containing both types of raw material. "Natural fibers have components such as cellulose and lignin, called natural polymers because their macromolecules are similar to synthetic polymers", explains the researcher. Sisal, cotton, jute, coconut fiber and sugarcane bagasse are some of the natural fibers tested and included in these materials composition. The resultant composite had mechanical properties many times greater than synthetic plastics. Mattoso says that in laboratory tests, these composites presented higher tensile strength and impact, beyond the fact that they are up to three times more rigid compared to 100% synthetic polymers. Another discovery in this research has opened an opportunity to use leftovers of processing natural fibers industries. "To our surprise, the waste collected in the process industries such as dust of natural fibers had the same characteristics as the whole fiber", he says. It means that the industry leftovers have the same quality as the whole natural fiber to formulate composites. Mattoso believes a new market may emerge from the use of industrial waste sisal processing, jute, cotton and sugar cane. The second stage of the research has developed a material entirely made from renewable sources, without addition of petroleum-based plastics. Starch, polysaccharides, cellulose derivatives and proteins were also tested to generate new materials. Before getting to edible plastic, the research team also developed biodegradable polymers. Motivated by demand for packaging absorbable by the environment in a short time researchers obtained plastics from natural materials. Finally, it came time of edible plastics, which required the incorporation of the highest standards of safety and hygiene in manufacturing process. The researchers conducted tests adding chitosan, a polysaccharide which forms the shells of crabs. This natural molecule has bactericidal properties which can increase the shelf life of foods. Guava paste sold in plastic made from guava, sushi involved in edible films replacing the traditional algae, turkeys sold in bags made of oranges prepared for baking and jellies in teddies format prepared with natural fruit. These are some possibilities imagined by Mattoso team for the applications of new technology. Scientific Highlights The scientific community has recognized the importance of this research. The article "Papaya and cinnamon, ingredients of antimicrobial films for food packaging", generated within the project, received the Featured article distinction by the Brazilian Society of Materials Research (SBPMat), in June 2014. Every month SBPMat chooses an article of materials research area recently published in journals that have a high impact factor. Another paper of the project entitled "Antimicrobial and physical-mechanical properties of pectin/papaya puree/cinnamaldehyde nanoemulsion edible composite films", which addresses the papaya film development, is among the most downloaded on the journal website Food Hydrocolloids. "These emphases show that the scientific community is also interested in this area and believe it holds potential", explains the researcher; adding the importance of national scientific partnerships, such as the ones with the "State University Paulista Julio de Mesquita Filho" (Unesp), and international partnerships of which highlights the work together with the Agricultural Research Service (ARS) of the United States. He also emphasized the participation of Embrapa Tropical Agroindustry (EC) professionals.