Brazilian scientists develop active and intelligent packaging

Researchers from the Food Engineering Laboratory (LEA) of the Polytechnic School (Poli) of USP are developing biodegradable packaging for foods made with raw materials of plant origin and agro-industrial waste, which serve as an alternative for the use of conventional plastic.
Work in the same laboratory goes further, and creates active and intelligent packaging, with substances such as antioxidants and antimicrobials that give them new uses. In one of the researches, for example, the addition of a substance from the grape skin to a package made with cassava starch may indicate whether red meat or fish are already in deterioration and can no longer be consumed.
So-called active packaging has substances capable of interacting with food to prolong its shelf life. Smart packaging, on the other hand, has mechanisms that allow detecting deterioration processes, temperature fluctuations suffered in storage or even indicating, by changing color, whether a fruit is ripe for consumption.
"One of our main challenges was to develop a resistant and malleable biodegradable film for packaging that could be produced on a large scale and at a competitive price compared to conventional plastic," says Carmen Cecilia Tadini, LEA coordinator and Director of Technology Transfer at the Food Research Center (FoRC), which collaborates with the studies. "At the same time, substances with differential attributes such as antioxidants or antimicrobials are researched," he adds.
The use of raw materials of plant origin and agro-industrial residues was the path trodden by the researchers to find a biopolymer formula capable of joining all these advantages.
One of the main promises tested in LEA is a malleable film based on cassava starch, additive with a substance called anthocyanin, obtained from the grape skin. When used to pack meat and fish this film changes color, from purple to blue, when food deteriorates. "In the process of deterioration, these foods release ammonia and the pH of the medium becomes more basic. When reacting to the pH change, anthocyanin changes color," explains Master student and food engineer Thaís Dale Vedove.
According to the LEA coordinator, this research has already overcome the main challenge to make the product industrially viable, which is to prevent the raw material from degrading when coming into contact with the high temperatures that occur in the extrusion process in the factories. "We are very close to solving the whole equation; it now lacks to stabilize the function of anthocyanin in the process and do biodegradability tests," says Tadini. "This is a disruptive innovation, because there are still no technologies that result in a malleable film, 100% biodegradable, and commercially viable," he adds.
Another route tested by the scientists was to create a hybrid material, composed of biopolymer and traditional polymers, which would have less environmental impact when discarded. The tested formula mixes babassu starch and polypropylene. "The goal is to maintain the properties of polypropylene and leave this material partially biodegradable, reducing by 30%, 40% the discarded residue," explains the chemist Bianca Chieregato Maniglia, researcher at FoRC and Poli, responsible for the research.
"The material made with the proportions of 70% polypropylene and 30% biopolymer has already shown that it is able to compete with conventional plastic," says the scientist.