Biofilm can double shelf life of egg

A biofilm that allows coating eggs and extending their shelf life was developed by researchers from the Center for The Development of Functional Materials (CDMF) – a Research, Innovation and Dissemination Center (CEPID) supported by FAPESP at the Federal University of São Carlos (UFSCar).
The material was produced based on chitosan, a natural polymer extracted from the shell of crustaceans such as shrimp, lobster and crab. In addition to eggs, it can be used to coat various food packaging, giving greater mechanical resistance and protection against microorganisms. The work was collaborated with scientists from the Federal University of Grande Dourados (UFGD).
"In addition to increasing resistance and having antifungal and bactericidal properties, the biofilm allows to seal microcracks and pores on the surface of eggs. This results in an increase in shelf life of the product," Luiz Fernando Gorup, visiting professor at UFGD and project coordinator alongside Eduardo José de Arruda, from the same university, told FAPESP Agency.
Arruda estimates that the coating extends the durability of the egg from 30 to 50 or up to 60 days, depending on storage conditions.
The material, which has already been filed with the National Institute of Industrial Property (INPI), was obtained through the association of chitosan and ammonium quaternary sea fare s adhering sof all commercially available generations.
These compounds, with antimicrobial properties, are used in controlled concentrations in disinfection food industries and as household sanitizers. The combination with chitosan at a given ideal concentration resulted in polymeric mixtures in which the salts of ammonium quaternary are homogeneously dispersed or contained in the structure of the material.
"These polymeric mixtures can be used in the forms of solution, emulsion, gel and dispersions, or even contained in other natural or synthetic matrices or supports," Gorup explained.
In liquid form, for example, the material can be sprayed in aviaries directly on the eggshell or in the disinfection bath of the product, in the hygiene step.
By losing water quickly and drying, the polymeric mixture returns to its initial polymer state, with chains of ammonium quaternary salts intertwined in its structure.
Similar to a flexible varnish, the material forms a biofilm that prevents the colonization of fungi and bacteria on the surface of the egg shell, preventing microorganisms from penetrating through microcracks or pores. In addition, when coating the product, it prevents moisture loss, controls gases and, consequently, prevents the loss of egg mass by evaporation, protecting the food throughout the chain, from production to commercialization.
"We found, in laboratory tests, that eggs covered with the material lose 40% less mass than those without protection with the material," Gorup said.
- Marketing plans
The idea is that the new material be made available for commercialization and application in aviaries by spraying or hygiene baths, after the polishing stage of the eggs, prior to the selection by size.
The product can be sprayed by means of a conventional spray when passing through the conveyor belt to be packaged.
"Our goal is to develop with producers a solution already in the ideal concentration for application through a simple process, so as not to financially affect the commercial egg production chain, as they are very cheap products," gorup said.
In the researchers' assessment, the solutions based on ammonium quaternary used today in the spraying of incubable eggs for product disinfection are not fully effective for fighting salmonella and other organisms.
This is because, when drying, the ammonium quaternary sea the saipers present in these solutions easily detach from the surface of the egg shell by any mechanical abrasion during transport, for example.
"In the case of the biopolymer there is no such risk, because the particles of the compound are homogeneously dispersed on the surface," he compared.
- New solutions
Researchers are now developing polymeric blends with new bioactive compounds to cover not only eggs, but also fruits and legumes. The idea is to develop "smart" packaging for food.
Some of the advantages of new compounds in development, compared to natural polymers such as chitosan, chitin, alginates and pectins, are better cost-effective and more consumer and environmental safety.
The new compounds could be used in a complementary way to polymer coatings and even in special applications for various food products and packaging.
Thus, they would have less toxicity compared to conventional sanitizers used today for disinfection of fruits, vegetables and legumes and could be used to produce plastic films and other products for coating packaging and surfaces, Gorup explained.
"We believe that the polymer based on this compound has great potential to be used as a bioprotective film for fruits and legumes and even for the production of food packaging," said the researcher.