Nofima scientists have studied which nanomaterials are suitable for encapsulating natural antimicrobial agents. The purpose is to make food packaging greener.

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Wenche Aale Hægermark  

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The most important reason for packaging food is to keep it fresh and safe for as long as possible. Increased shelf life reduces food waste. In addition, there is an expectation of greener food packaging. The climate footprint must be as small as possible for both food and packaging solutions. The challenge the researchers face is to develop greener packaging solutions that also ensure that food keeps just as long and fresh as today’s packaging provides.

Natural plant oils need protection

“We are working on the possibility of combining active packaging solutions based on naturally active components with more environmentally friendly packaging solutions. These natural components are found in natural plant oils that have antimicrobial properties, thus inhibiting bacterial growth so that food has increased shelf life”, explains Nofima scientist Jawad Sarfraz.

One challenge is that the plant oils, or more precisely the active components of the plant oils, are very volatile. That means that they ‘disappear’ after a certain amount of time. The components are also sensitive to oxygen, heat and light, which make it difficult to process them in their natural state. This is where nanomaterials come in. They can form a protective environment around the sensitive plant oil components.

Nanocarrier = nanomaterial with encapsulation abilities

The Nofima scientists have investigated nanomaterials that are able to encapsulate things such as organically active components, and then adjust the effect so that the components are released after a certain amount of time. These nanomaterials are called nanocarriers. The technique is well known in research on biomedical applications. This involves using a nanomaterial to transport a specific type of medicine to a specific place in the body in order to achieve the best possible effect.

“We have investigated and compared different nanocarriers to take a closer look at which ones can work best in a food packaging application” says Tina Gulin-Sarfraz. She is a postdoctoral researcher at Nofima and works on the PackTech project.

­Results from medical research provide inspiration

Other research groups have previously investigated how commercially available nanoclays can be used to encapsulate the sought-after active components of plant oils in order to develop new, active packaging solutions that have a smaller climate footprint. Common to these is that little thought has been given to the possibility of adapting the nanocarrier to the specifically intended use. Nanoclay is a natural type of clay.

“Interest in so-called synthetically produced porous silica particles is now growing. This is a harmless mineral found naturally in large quantities. It is widely used in medical research and is a common food additive called E 551. We believe that this nanocarrier is the most relevant with regard to food contact”, says scientist Jawad Sarfraz.

Partikler fra Tailoring silica particles

The silica particles offer great design possibilities, and researchers are able to tailor the particles so that they protect a specific active component.

“We can tailor the pore structure, the surface area and the surface chemistry, and adapt to the components we are going to encapsulate” explains Tina Gulin-Sarfraz. She adds that other important nanocarrier criteria include how effective they are at encapsulating the active components and being able to make the components available at just the right time.

The Nofima scientists have found that the active volatile components are encapsulated more effectively when using synthetically produced silica particles rather than commercially available nanocarriers.

“It may seem counterproductive to use a commercially available nanocarrier that is not adapted to the active component. We must develop tailor-made solutions where the nanocarrier is adapted to the relevant active component. We also need exact knowledge about how the nanocarrier preserves the properties of the active component, and how these can be activated in an appropriate way”, concludes Tina Gulin-Sarfraz.

Equipment for the characterisation of nanoparticles

Synthesis and characterisation of nanomaterials is a relatively new field of research at Nofima, and the infrastructure is gradually being built up.

A Zetasizer, which is used for the characterisation of nanoparticles, is in place. This makes it possible to study the size and surface charge of the nanoparticles.

Gas chromatography – mass spectrometry (GC-MS) and spectroscopic techniques are available in house. These methods are used to study the encapsulation and release of active components. Other characterisation methods are used in collaboration with UiO and NMBU.

About nanotechnology and nanomaterials

A nanometre is one-billionth of a metre. When the dimensions of a material enter the nanoscale, major changes occur in the reactivity of the material. Nanomaterials have a much greater surface area per unit mass compared to larger objects. Porous nanomaterials can have a surface area greater than 1000 m2/g. A result of the high surface-to-volume ratio is that the optical, electrical, physical, mechanical and magnetic properties can be changed.

These unique nano-effects are the basis for the new and fascinating applications of nanomaterials. Nanomaterials can potentially be used in the field of food packaging to improve the barrier properties of the packaging material, and to develop new active and intelligent packaging systems.

Fakta om forskningen

  • Forskningen er utført i prosjeket PackTech
  • Finansiert av Nofima