02.10.2013

The Nano Approach to Flexible Packaging

While the focus for flexible packaging suppliers has been firmly on sustainability issues as much as performance in recent years, a new generation of packaging technologists is looking at new, and potentially ground breaking, nanomaterials and coatings to create new products. Nano is showing great promise across a number of areas and is gaining increasing acceptance with regulatory authorities. For example, the European Food Safety Authority (EFSA) approved three nano coatings for use with material in contact with food earlier this year.

Silicon dioxide, titanium nitride and carbon black are all authorized for use in plastic food contact material. Major energy savings can be achieved when making plastics film containing these nano chemicals, up to 38 percent has been claimed. A spokesman for the Nano Industries association (NIA) says, “These materials can be used by manufacturers of food packaging to improve the properties and characteristics of their products. The benefits these nano materials brings to packaging is to be explored and commercialized by food packaging manufacturers.”

Film Made of Shrimp Shells
More exotic ideas are also beginning to surface. For example, Nofima is participating in a major EU-financed project in which “active” packaging based on raw materials from shrimp shells improves and conserves food products, and after use, the packaging biodegrades. Called the Chitopack project, the goal is to expand on the positive properties of chitin nano-fiber to development new food packaging. Project researchers are looking at biodegradable packaging made of chitin and chitosan from shrimp shells that will improve and conserve food products. These are biocompatible, naturally biodegradable polymers, non-toxic and show antimicrobial and UV adsorption characteristics. Used as an integrated part of the packaging, chitosan can have an antibacterial affect on the food. Materials range from hard bioplastic to thin film that can come in direct contact with food products. Elsewhere, at Michigan Technological University, scientist Jaroslaw Drelich has found a new way to destroy bacterial infections on flexible materials. His innovation relies on copper, long recognized for its antibiotic properties. Drelich has discovered how to embed nanoparticles of this metal into vermiculite, an inexpensive, inert compound sometimes used in potting soil. If it were incorporated into food packaging materials, it could help prevent a variety of food borne diseases, including listeria and salmonella, according to initial tests. The copper-vermiculite material mixes well with many other materials, such as plastic, so it could be used in a variety of packaging materials. And because the cost is low – 25 cents per pound at most – it would be an inexpensive, effective way to improve the safety of the food supply, especially fruits and vegetables.

Scientists from ETH Zurich have developed a nanomaterial that protects other molecules from oxidation. Unlike many existing active substances, this antioxidant has a long shelf life, which makes it ideal for industrial applications. Antioxidants are found in many fruit and vegetable varieties, coffee, tea and red wine and are generally regarded as healthful; they are also used as food additives to preserve items for longer. The problem in using these antioxidants is that many of these molecules are not actually very stable. Researchers have now developed a special nano antioxidant that is considerably more stable than its conventional counterparts, so it can be stored more easily and is effective in smaller amounts. ETH Zurich's researchers coupled gallic acid with silicon dioxide nanoparticles to stabilize the antioxidant. In addition, the nano antioxidant is temperature-resistant and could protect food that is pasteurized or polymers that are produced at high temperatures. Conventional antioxidants become inactive at these temperatures.


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