University of São Paulo: New method to extract protein from corn should put more bioplastics on the market

Bioplastics made with zein may decompose in about three months. In Brazil, this type of product does not exist due to the low efficiency of the current protein extraction processes, which may be even more regrettable considering that the country is the fourth largest producer of corn grains in the world. An application for a “green patent” has already been submitted to the National Institute of Industrial Property (Inpi) – Photo: Pexels

New method to extract protein from corn should put more bioplastics on the market
Technique created by a researcher from USP makes zein (corn protein) more efficiently obtained, allowing ethanol plants and bioplastics industries to have a profit of at least 200%

UA new technique for extracting zein (corn protein) from residues from corn kernels will allow the insertion of bioplastics in Brazil that use the compound as a raw material. Currently, the methods used in the country to extract protein from waste are unable to remove even half of it, which discourages companies from investing in its use. However, with the new strategy proposed by a researcher at the São Carlos Institute of Chemistry (IQSC) at USP, the zein may be totally removed, allowing plants interested in extracting it for sale or industries that are thinking about producing sustainable bioplastics and biodegradable can make a profit of at least 200%. An application for a “green patent” for the new technique has already been submitted to the National Institute of Industrial Property (Inpi).

“In addition to being more efficient, our technique is cheaper, simpler and faster than those currently used to extract zein from corn grain residues”, says Sérgio A. Yoshioka, author of the work and professor at IQSC. The conventional technique for obtaining the protein uses the residues of corn grains mixed with common ethanol, which undergoes evaporation and solubilization processes to allow the zein to be extracted. In the method idealized by the teacher, the procedure is basically the same, but ethanol has its acidity or alkalinity altered, generating chemical reactions that allow the extraction of a larger amount of the substance (close to 100%).


From the zein extracted with the new technique, the researcher produced some 100% biodegradable, edible, compostable and recyclable biomaterials, such as soap and straws. Because corn protein can also be used as a film to coat food and prevent the invasion of bacteria, increasing the shelf life of products, the teacher took advantage of the raw material obtained to coat a cheese and illustrate its application. In Brazil, there are no bioplastics manufactured with zein due to the low efficiency of current protein extraction processes, which may be even more regrettable given that the country is the fourth largest producer of corn grains in the world, according to the Brazilian Institute of Geography and Statistics (IBGE).


The bioplastics sold today use corn or cassava starch as a raw material, compounds that are less resistant to moisture than zein, which ends up being more durable. With regard to films for coating food, nowadays they are generally made from pectin or chitosan, substances that have less mechanical resistance than zein when they are in high humidity environments. Initially, the IQSC researcher’s idea is to use corn protein to coat sweets and produce edible straws. Because it is a highly protein and safe product, zein can be consumed without any problem.

A pilot plant is already being set up in Criciúma (SC) to incorporate the new zein extraction technique from corn kernel waste in order to develop and patent new processes and products using the protein. The expectation is that this year the industry will produce tons of the compound per day. According to Professor Sérgio, if the value of the zein remains around R $ 40.00 per kilo (kg) and the sack of corn kernels does not exceed R $ 90.00 / sack, corn ethanol plants may innovate with technology and make a profit of at least three times in the sale of zein, in addition, of course, to become much more sustainable and renewable companies. At the end of this production chain are consumers, who, in turn, will have a new option to buy products that do not harm the environment,

One of Professor Sérgio’s goals, as well as that of all researchers working with the development of different types of bioplastics, is to provide new alternatives to ordinary plastic, of petroleum origin, which can take up to 100 years to degrade and cause serious damage. impacts on the environment, such as contamination of rivers and intoxications or deaths of animals that routinely ingest products discarded incorrectly, such as sea turtles and whales. Several Brazilian cities have even banned the use or distribution of disposable plastics, such as cutlery, glasses, plates, marmitex, juice straws, among others. Bioplastics made with zein, on the other hand, may decompose in about three months.

The work developed by the USP researcher was a consultancy for the startup GreenB Biological Solutions, which is responsible for setting up the pilot plant in Criciúma. The project is funded by the Centelha-SC Program, offered in partnership by the Foundation for Support to Research and Innovation of the State of Santa Catarina (Fapesc), by the National Council for Scientific and Technological Development (CNPq), by the Financier of Studies and Projects ( Finep) and the Ministry of Science, Technology and Innovations (MCTI).

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