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A biodegradable plastic bag


Product developed at FEA can also be used as a fruit protection film.

In place of the plastic bag made from petroleum-derived raw materials, a product made from natural polymers only.

Instead of material that takes up to a century to degrade in nature, a fully biodegradable substitute that decomposes in contact with the environment in a matter of days. The alternative, long craved by society, has just been made possible by the food engineer Farayde Matta Fakhouri.

She has developed for her Ph.D. thesis, recently defended at Unicamp, a flexible film that can be used in the manufacture of plastic bags, those provided by supermarkets, and fruit protection films.

Detail: Because it is basically composed of starch (corn and cassava), gelatin and a fatty acid, biofilm can be edible. The work was supervised by teachers Fernanda Paula Collares and Lucia Mei.

Farayde's research continued her work in the master's degree, whose orientation fell to Professor Carlos Grosso. The researcher's pursuit was to develop a packaging that was biodegradable and used only natural polymers. "Currently, the market even offers biodegradable materials, but using raw materials derived from petroleum, which is a non-renewable source," he explains. According to her, the study was very laborious. Before reaching the ideal formulation, she tested eight starch types at two different concentrations. It then evaluated three different gelatin concentrations and two types of plasticizer, which is responsible for the suppleness of the biofilm, as well as six different fatty acids.

The biodegradable plastic bags, according to Farayde, were produced by the extrusion method followed by blowing. Compared to products found on the market, they are slightly less resistant. However, the food engineer believes it will be enough to make minor changes in formulation to correct this deficiency. "Nowadays, thanks to the possibilities offered by nanotechnology, we can already use nanosilicas or nanocomposites that can give greater resistance to the film", he infers. Packaging made from natural polymers alone, the study author points out, tends to break down in nature very quickly. "In this case, everything seems to be a process that should take days," he predicts.


Fruit before the plastic bath.


Fruit after plastic shower.

Bioplastic-protected grapes: composed of starch, gelatin and a fatty acid, the biofilm can be edible by the researcher's calculations, who will continue to improve her postdoctoral innovation. within two years. "As the most difficult stage has been overcome, I believe that the transfer of this technology to the productive sector can be done without major obstacles."

Farayde also points out that in addition to serving this type of packaging, biodegradable film can also be used to protect fruits. As long as water is added to the formulation, it assumes the consistency of a "syrup". After being bathed in this formula, the fruit gets a film around it, which acts as a very thin and transparent shell.

"In the tests we did, the grape protected by this film had its shelf life extended by 20 days," says the food engineer.
If it is in fact transformed into a commercial product, the biodegradable plastic film developed by Farayde should contribute to the reduction of environmental aggression. In addition to being widely used by Brazilians, conventional plastic bags also serve to dispose of household waste in countless households in the country.

As this material is little recycled in Brazil, unlike aluminum cans, most packaging ends up being discarded in nature, which causes a huge environmental problem. Currently, of the total waste produced on a national scale, between 5% and 10%, varying by region, are made up of plastics. Of these, only 20% go through recycling processes.

Adapted from: Unicamp Journal - 22/03/2009

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