Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


RUDN University chemists obtained new material for antibacterial food coatings


RUDN University chemists have developed a simple and convenient method for producing derivatives of the natural polymer chitosan. These derivatives are non-toxic and have a pronounced antibacterial activity at the level of modern antibiotics. These substances can be used in the production of antibacterial protective films for food. The article is published in the journal Food Chemistry.

Preservatives are widely used in the food industry. They are necessary to extend the shelf life of products. On the other hand, preservatives reduce food quality. Some of them can cause allergies (benzoic acid) or be toxic (nitrates, nitrites).

RUDN University chemists have developed a simple and convenient method for producing derivatives of the natural polymer chitosan. These derivatives are non-toxic and have a pronounced antibacterial activity at the level of modern antibiotics.

Credit: RUDN University

Synthetic waxy substances used to coat fruits can be carcinogenic (biphenyl is prohibited in the US and EU). This explains the importance of finding new preservatives that are effective and safe.

Chitosan is a natural polymer derived from chitin, the main component of insect and crustacean shells. It has antibacterial properties and is already used in the food industry for packaging and coating products with a protective film. However, its activity is much inferior to antibiotics.

To obtain non-toxic and highly active derivatives of chitosan, RUDN University chemists Andreii Kritchenkov and Margarita Kurasova and their colleagues have modified chitosan with organic azides by "sewing" them to the polymer chain.

Azides are derivatives of hydrazoic acid HN3. Both organic and inorganic azides are toxic, but their compounds with chitosan are not poisonous. Antibacterial activity of the obtained substances, azido chitosan, was significantly higher than that of chitosan.

The experiment showed that samples of polymers based on chitosan had antibacterial activity at the level of antibiotics. The researchers compared this parameter for azido chitosan with the two most common antibiotics - ampicillin and gentamicin.

Antibacterial activity was determined by diffusion into the agar (nutrient) layer. A disk of filter paper impregnated with the test substance (or comparison antibiotic) was placed on the agar layer sown with a bacterial culture. The substance penetrates the agar, killing bacteria or slowing their reproduction. As a result, a growth suppression zone is formed around the disk, which differs from the rest of the agar surface visually. The value of an antibacterial activity is estimated by the diameter of the formed zones. Toxicity was determined by a standard colorimetric test.

An obtained derivative of chitosan - azido chitosan - cleaned Staphylococcus aureus from a zone of 26 mm in diameter (the indicator for ampicillin was 30 mm), and of 18 mm for Escherichia coli (in gentamycin it was 22 mm).

That is, the polymer has almost the same antibacterial activity as antibiotics. This is extremely important, because the use of antibiotics as components of antibacterial films is highly unacceptable because it leads to the emergence of resistant strains of bacteria. Chitosan compounds do not have this disadvantage.

New chitosan derivatives can be used as harmless and effective preservatives to create protective films for food on their basis.



Novel non-toxic high efficient antibacterial azido chitosan derivatives with potential application in food coatings.

Food Chemistry

15 December 2019, Volume 301, 125247

Research area: chemistry

RUDN University

Media Contact

Ekaterina Mareeva 

Ekaterina Mareeva | EurekAlert!
Further information:

More articles from Life Sciences:

nachricht 'Flamenco dancing' molecule could lead to better-protecting sunscreen
18.10.2019 | University of Warwick

nachricht Synthetic cells make long-distance calls
17.10.2019 | Rice University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Solving the mystery of quantum light in thin layers

A very special kind of light is emitted by tungsten diselenide layers. The reason for this has been unclear. Now an explanation has been found at TU Wien (Vienna)

It is an exotic phenomenon that nobody was able to explain for years: when energy is supplied to a thin layer of the material tungsten diselenide, it begins to...

Im Focus: An ultrafast glimpse of the photochemistry of the atmosphere

Researchers at Ludwig-Maximilians-Universitaet (LMU) in Munich have explored the initial consequences of the interaction of light with molecules on the surface of nanoscopic aerosols.

The nanocosmos is constantly in motion. All natural processes are ultimately determined by the interplay between radiation and matter. Light strikes particles...

Im Focus: Shaping nanoparticles for improved quantum information technology

Particles that are mere nanometers in size are at the forefront of scientific research today. They come in many different shapes: rods, spheres, cubes, vesicles, S-shaped worms and even donut-like rings. What makes them worthy of scientific study is that, being so tiny, they exhibit quantum mechanical properties not possible with larger objects.

Researchers at the Center for Nanoscale Materials (CNM), a U.S. Department of Energy (DOE) Office of Science User Facility located at DOE's Argonne National...

Im Focus: Novel Material for Shipbuilding

A new research project at the TH Mittelhessen focusses on the development of a novel light weight design concept for leisure boats and yachts. Professor Stephan Marzi from the THM Institute of Mechanics and Materials collaborates with Krake Catamarane, which is a shipyard located in Apolda, Thuringia.

The project is set up in an international cooperation with Professor Anders Biel from Karlstad University in Sweden and the Swedish company Lamera from...

Im Focus: Controlling superconducting regions within an exotic metal

Superconductivity has fascinated scientists for many years since it offers the potential to revolutionize current technologies. Materials only become superconductors - meaning that electrons can travel in them with no resistance - at very low temperatures. These days, this unique zero resistance superconductivity is commonly found in a number of technologies, such as magnetic resonance imaging (MRI).

Future technologies, however, will harness the total synchrony of electronic behavior in superconductors - a property called the phase. There is currently a...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

International Symposium on Functional Materials for Electrolysis, Fuel Cells and Metal-Air Batteries

02.10.2019 | Event News

NEXUS 2020: Relationships Between Architecture and Mathematics

02.10.2019 | Event News

Optical Technologies: International Symposium „Future Optics“ in Hannover

19.09.2019 | Event News

Latest News

Energy Flow in the Nano Range

18.10.2019 | Power and Electrical Engineering

MR-compatible Ultrasound System for the Therapeutic Application of Ultrasound

18.10.2019 | Medical Engineering

Double layer of graphene helps to control spin currents

18.10.2019 | Physics and Astronomy

Science & Research
Overview of more VideoLinks >>>