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Latest Advances in Barrier Food Packaging Plastics

Donald Rosato – Jan 31, 2019

TAGS:  Additives for Packaging     Barrier Solutions for Food Packaging    

Latest Advances in Barrier Food Packaging Barrier packaging plays a vital role in protecting the quality of food from spoilage or degradation caused by oxygen, moisture, and bacteria.

Passive barrier layers limit oxygen and water vapor transmission into the package while vacuum packaging or modification of the gas in the package by purging with nitrogen or carbon dioxide provides additional protection.

The push for more recyclable packaging is driving growth in mono-material, multilayer film structures that use active packaging solutions, such as oxygen absorbers, to maintain or improve properties.

Research to understand the fundamentals behavior of barrier materials continues to offer fresh insights and generate new materials.

Let’s take a look at Barrier Food Packaging advances...

#1. A. Schulman’s Simplified Multi-layer Structure

LyondellBasell’s A. Schulman division has completed research where multi-layer barrier structures could be simplified if EVOH, the oxygen barrier layer, could be protected in a different way. EVOH (ethylene vinyl alcohol) is commonly used in barrier film structures because of its high oxygen barrier.

However, its sensitivity to moisture means that it must usually be protected within a multilayer structure of its own, which makes manufacturing the film more complex. Rather than doing this, which usually means making at least a five-layer structure, A. Schulman proposed protecting the EVOH by incorporating it into a polymer blend. This is a traditional method for improving the gas barrier of a polymer by blending it with another higher barrier polymer.

A. Schulman’s current approach is different to some previous efforts as it uses a pre-compounding process to ensure that the multilayer morphology forms after resins are extruded into thin films. This is because the choice of polymeric compounds, in this case, EVOH and a highly dispersible polyolefin such as LLDPE (Linear Low-Density PolyEthylene), with proper compatibility and a viscosity match ensures that they will form into ‘linear bands’ when extruded, which approximates to the structure of a multilayer film.

One blend formulation, called B24, gave similar barrier properties as actual multilayered films. This film could easily be embedded into other multilayer films. Atomic force microscopy (AFM) images show that A. Schulman’s directly extruded B24 blend has a similar structure to a traditional multilayer film.

A. Schulman’s Directly Extruded B24 Blend (L), Traditional Multilayer Film (R)
AFM Image Shows A. Schulman’s Directly Extruded B24 Blend (L), Traditional Multilayer Film (R)

#2. AIMPLAS Encapsulated Additive Compounding Methods

Spain’s AIMPLAS researchers have developed encapsulated additive compounding methods in tandem with suitable resin carriers. Encapsulation technology offers release control, thermal and shear protection, and the additional advantage to handle a powdered additive versus a traditional liquid.

For example, an encapsulated garlic extract additive, which has both antibacterial and antioxidant capabilities was compounded into a into a PLA (PolyLactic Acid) resin matrix. A container for fresh salad using the additive showed a significant difference from the control container with no active additive after four days at room temperature (RT).

AIMPLAS PLA Salad Packs (4 Days, RT); Pack (L) with Encapsulated Garlic, Control (R)
AIMPLAS PLA Salad Packs (4 Days, RT); Pack (L) with Encapsulated Garlic, Control (R)

#3. Bemis Odor Recognition Packaging

Organoleptics such as odor recognition can affect the consumer’s impression of freshness in vacuum-packaged meat products. A new technology from Bemis is intended to provide a solution to this problem. When combined with low oxygen transmission rate (OTR) films, vacuum packaging extends meat shelf life by reducing headspace oxygen. This in turn, decreases the growth rates of spoilage bacteria and minimizes the organoleptic effects of lipid oxidation. However, Bemis R&D claims that an unintended consequence of using low OTR packaging is the development of confinement odor.

Although this odor quickly dissipates once a package is opened; its detection by the consumer has a negative impact on acceptability. Confinement odor is a particularly vexing problem for the poultry industry.

In odor suppression Bemis technology uses potassium sorbate, an FDA (U.S. Food & Drug Administration) compliant food ingredient. It is compounded into the food-contact layer of the packaging inside an oxygen barrier. The novel combination of potassium sorbate modification and low OTR packaging films results in slower bacteria growth rates as well as suppression of confinement odor. The new Bemis technology will help poultry processors estimate ‘sell-by’ dates with added precision and better corroborate consumers’ freshness expectations. Additionally, shelf life extension techniques like this help producers reduce food waste.

Bemis Schematic Showing Latest Active Odor Control Solution for Vacuum Packed Meat
Bemis Schematic Showing Latest Active Odor Control Solution for Vacuum Packed Meat

#4. Nova Chemicals Grease-Resistant HDPE Films

Nova Chemicals has developed a family of HDPE (High Density PolyEthylene ) films with high grease resistance making them suitable for a range of food packaging applications. As part of the process, Nova devised a semi-quantitative method to measure the level of grease or oil permeation. It is now possible to develop cost-effective and recyclable PE (PolyEthylene) film packaging structures with good grease barrier performance by using certain single site catalyzed PE resin architectures. Grease-resistant plastic packaging usually uses higher specialty resins such as EVOH (Ethylene Vinyl alcohOL), but these make recycling more difficult.

Nova began a study to assess the effectiveness of its PE resins for grease resistance, and as part of this, developed a new measuring method. Nova tested a range of three- and nine-layer films, containing recyclable and non-recyclable resins, including traditional high barrier materials like EVOH, as well as its own Surpass LLDPE (Linear Low-Density PolyEthylene) and HDPE resins. Nova researchers found that some formulations using only polyolefins had a grease barrier that was comparable with EVOH and that its HDPE had a particularly strong effect.

Nova Chemical’s Grease-Resistant HDPE Films for a Range of Food Packaging Applications
Nova Chemicals Grease-Resistant HDPE Films for a Range of Food Packaging Applications

#5. Life's Technology of Food Shelf Life Enhancemet

One of the challenges for food packagers is to extend the shelf life of foods with no or reduced preservatives. Antimicrobials in the packaging can help extend shelf life, but they must also be approved for use in food-contact plastics.

An additive from Thailand-based Life Materials Technologies (LIFE DJ/AM-00-1A) combines an inorganic antimicrobial with a molecular sieve, with the two working synergistically in plastic packaging to help delay spoilage of foods. The LIFE DJ/AM-00-1 Aadditive complies with biocide regulations in the US and EU and is approved for use in food contact plastics globally.

Other potential natural, edible additives include highly antioxidant-based substances that can be obtained from olive and vine industry byproducts. Extracts with anti-fungal and antibacterial properties have also been obtained from garlic and onion production and from orange peel. These have been shown to have a proven ability to improve the shelf life of foods such as strawberries and fresh cheese.

Albis’ Monomaterial Film Compounds Replace Hard-to Recycle Multi-layer Packaging
Albis’ Monomaterial Film (above) Compounds Replace Hard-to Recycle Multilayer Packaging

Food Packaging Professionals: Stay Alert!

Stay updated on latest advances in barrier food packaging technology to identify where the true potential and new opportunities exist for you and make better R&D decisions. Join the course: Food Packaging: Latest Barrier Solutions today!

Latest Barrier Food Packaging Solutions

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