Nanoclay – A Feasible Alternative for Food Packaging Industry?

Incorporation of nanoclay in polymer is an emerging technology for optimizing food packaging material that can meet the stringent regulations imposed on packaging industry. However, a few challenges are associated with its use in food packaging industry. If these challenges can be successfully overcome, nanoclay technology will be widely adopted.

The world is facing an existential crisis due to environmental degradation and large-scale pollution. Plastic is a major pollutant choking the planet. Intense use of plastic across all sectors has led to this situation. One of the main users of this material is the food packaging industry. The high demand for minimally processed food, such as ready-to-eat and ready-to-cook options, has compelled food producers to come up with innovative alternatives for packing food that preserve nutrition and are simultaneously cost effective.

The Rise of Nanoclay Technology

Polymer-based packaging technology is most accepted in food packaging industry. For preserving food, the packaging must have barrier resistance, long shelf life, heat resistance, flexibility, and antimicrobial properties. To enhance these properties, nanoclay is embedded into the polyolefins (polypropylene/polyethylene) as tiny particles used in packaging. Nanoclay is a nano agent used to prepare nanocomposites for food packaging.

The incorporation of inorganic material in the organic polymer matrix led to the discovery of nanocomposites. Nanocomposites have optimized packaging and significantly improved the properties of biodegradable polymers.

Polyolefins are known for their nonpolar, hydrophobic, beneficial mechanical, and barrier properties making it suitable for bottles, wraps, sachets, and films. Due to their grease resistance and gas barrier properties, nanoclays, such as montmorillonite (MMT) or organophilic MMT, are incorporated into the polymer. MMT nanoclay also exhibits antimicrobial function against gram-positive and gram-negative bacteria. Studies show that antimicrobial property of low-density polyethylene/Ag/titanium dioxide nanocomposites prepared using sol–gel and melt-mixing methods could be increased against pathogens such as E. coli, S. aureus, C. albicans, and A. niger.

Challenges

Various challenges are associated with the use of nanoclay:

• A possible risk is involved with their use in the food packaging industry; aluminum in most of the clays is a concern due to its neurotoxic effects, and the use of synthetic additives in nanoclay pose a high risk. There is a possibility of contamination due to migration of nanoparticles into the food components. 
  
• Furthermore, the use of synthetic organic modifiers applied in producing certain nanocomposites have cytotoxic effects.
  

Inductively coupled plasma (ICP), graphite furnace atomic absorption spectrometry (GFAAS), and high-performance liquid chromatography (HPLC) are few of the various experimental techniques to identify the migration of nanoclay to nanocomposites.

Leaching of nanoclay can be identified through technologies, such as scanning and/or transmission electron microscopies (SEM and/or TEM) with X-ray energy dispersive spectroscopy (EDS). These tests can help ensure that food remains safe and edible once the packaging is removed.

Regulations

Several regulations have been implemented on the use of nanoclay in food packaging industry in regions such as the US and Europe. For instance, EU Regulation No 10/2011 gives authorization based on the size of the additive in the food contact material and the surfactants used for the modification of nanoclay. Further, EU regulates that the nanocomposites must comply with a total migration limit of 10 mg dm⁻². While in the US, the use of bentonite and kaolin fall under “generally recognized as safe” (GRAS) category.

Conclusion

The rising need for novel packaging technology that complies with the regulation and caters consumer demand will support the growth of nanoclay technology. The optimal conditions used to produce clay nanocomposites and food contact regulations would help resolve the concerns associated with quality of food. Nanoclay could become an important ingredient in food packaging material.