A team of Purdue University, US, researchers have manufactured an innovative new process that uses cellulose nanocrystals (CNCs) to create advanced barrier coatings for food packaging. The technology can be used to create non-toxic and biodegradable packaging solutions. The shelf-life extending process also has the potential for a large-scale rollout but it will require industrial partners to bring the technology to market.

CNCs are an alternative renewable raw material derived from abundant resources such as wood and plants. They have properties including non-toxicity, biodegradability, high specific strength, high thermal conductivity and optical transparency, all of which make them excellent components for advanced food packaging.

“The main issues were in getting sufficient alignment of the cellulose nanocrystals and then actually measuring the extremely low gas permeabilities without interference from other things, like substrates. once we solved those issues, we realized that the CNC coating is an extremely good barrier layer,” Jeffrey Youngblood, Professor of Materials Engineering at Purdue University and project lead, tells PackagingInsights.

The Purdue manufacturing technique is also scalable since it is a roll-to-roll manufacturing process using waterborne polymer systems. CNCs are highly crystalline and easily dispersed in water, so manufacturers can control the structure to eliminate the free volume and end up with only the properties that are needed for the barrier material.

“once we realized that aligned CNC films were so good, we developed a way to utilize Roll-to-Roll gravure coating to apply the aligned films at a pilot scale. It is still smaller than any manufacturer, but R2R gravure coating is a scalable method, unlike most lab methods,” Youngblood adds.

The Purdue Research Foundation Office of Technology Commercialization helped secure a patent for the technology. It is available for licensing.

The research team is now working to improve the barrier performance even further. They want it to be competitive with the absolute best barrier layers in the world.

Currently, high humidity performance poses an issue. “Our performance drops a bit at high humidity, but we believe we know how to solve it, as has been done in other materials,” Youngblood explains.

He notes that the team has achieved barrier properties equal to or better than EVOH coatings, which is a standard workhorse barrier material.

“Application areas will really depend on the ultimate performance we achieve. However, as the material is high clarity, high performance and cellulose – so non-toxic and biodegradable – we think that food packaging is the sweet spot,” he notes.

The Purdue manufacturing technique achieved top honors at one of the worlds largest technical conferences for the packaging industry. Md Nuruddin, a graduate student on the team, received the award for best poster during PaperCon 2019 this month in Indianapolis, US.

According to Credence Research, food packaging is a growing billion-dollar market and the overall predicted growth is expected to reach 6 percent by 2024. Advanced barrier coatings, which help to protect grocery items such as foods and beverages, are growing by as much as 45 percent each year.

“Winning an award such as this at Papercon from experts in the packaging field is validation that our approach has merit,” Youngblood says.

Food waste is widely considered to be one of the biggest sustainability challenges and one that advanced barriers can help to minimize. Dr. Nina McGrath, Senior Manager for Food & Health Science for European Food Information Council EUFIC tells PackagingInsights that an estimated 1.3 billion tons, or 32 percent of all food produced globally, are lost or wasted each year.

“This also represents an enormous waste of the valuable resources used in food production, such as water, energy, work and money,” McGrath says.

Also working to eradicate the food waste problem, the NanoPack project has reported significant advancements in the shelf-life and quality extension of a range of foods when packaged in nano-active materials. Funded by the EU Horizon 2020 scheme, the project aims to mainstream nanotechnologies in commercial flexible packaging.

NanoPack plans to have all technological developments ready by the end of 2019, including a roadmap to facilitate the commercial uptake of the technology in “the nearest future.”

Innovation in shelf-life enhancing packaging is showing signs of progress, particularly within the food and vegetable category. Just recently, Seattle-based start-up StixFresh developed a sticker that can keep fruit and vegetables fresh for up to two weeks longer than usual.

Similarly, UK-based technologists, It’s Fresh! recently launched its latest shelf-enhancing product – Infinite – a new sustainable delivery system that utilizes a proprietary “active ingredient” that can be printed directly onto existing packaging for fruit, vegetables and even flowers. It is proven to prolong shelf-life and extend freshness and quality by absorbing the natural ripening hormone, ethylene.

A recent report by Fruit Logistica anticipates “significant innovation” in fresh produce packaging and supply chain management in the coming years. This prediction is based on increased consumer awareness of the environmental damage caused by food packaging and the need for greater shelf-life and efficiency in the supply chain.

By Joshua Poole