Researchers create a biodegradable, edible, antimicrobial and more resistant than usual plastic

By : Dr. Franyi Sarmiento, Ph.D., Inspenet, March 22, 2022.

Researchers at the Universidade Estadual Paulista, in Brazil, managed to create a biodegradable, edible, antimicrobial and more resistant plastic, using gelatin, clay and a nanoemulsion of black pepper essential oil, which can be used in the manufacture of food containers.

The study was carried out by the Hybrid Compounds and Nanocomposites Group (GCNH) of the Department of Physics and Chemistry of the Universidade Estadual Paulista (Unesp), at its campus in the town of Ilha Solteira, in Brazil. This work was supported by FAPESP and its results were published in the journal Polymers.

To manufacture its “bioplastic” –or “green plastic”, as it is also called–, the group used type B colorless gelatin as its main raw material, extracted from cow marrow and easily found in supermarkets and other commercial establishments.

“Gelatin was one of the first materials used in the production of biopolymers and it is still widely used due to its abundance, low cost and excellent film-forming properties,” says chemist Márcia Regina de Moura Aouada, a professor at the Faculty of Engineering of Ilha Solteira (Feis-Unesp) and coordinator of the study.

“However, containers made from biopolymers often exhibit characteristics that need to be improved to become comparable to those made from petroleum derivatives. This is especially important with regard to mechanical and vapor barrier properties. For this reason, we add Na+ cloisite clay to the gelatin”, comments the researcher.

With the addition of this clay, a more homogeneous film was obtained, capable of withstanding traction on the order of 70 megapascals (70 MPa) on average. In conventional polyethylene-based plastics, the tensile strength usually varies between 20 MPa and 30 MPa, less than half of that achieved with bioplastic.

“In addition to the clay, we also added a nanoemulsion of black pepper essential oil to the mix. The objective in this case was to obtain a more attractive edible package in terms of flavor and aroma. And that it could also extend the shelf life of the packaged food by adding antimicrobial and antioxidant components to the polymeric matrix,” says De Moura Aouada.

It should be noted that the bioplastic in question was designed to package beef in the form of hamburgers, a food that is quite susceptible to microbial contamination and has a very strong odour. But the general principle of adding clay and nanoemulsions of essential oils to the gelatin matrix can and will be extended to other types of food, with case-by-case variations in the type of essential oil and the proportion applied.

Apart from the aforementioned bioplastic, the group produces dressings based on bacterial cellulose. And edible packaging with nanostructures derived from cabbage puree, cocoa puree, cupuaçu puree (Theobroma grandiflorum), camu-camu extract (Myrciaria dubia, a fruit of the myrtaceae family) and nanoemulsions with potential application in industries of food, drugs and cosmetics.

Source and Photo: DICYT: