Packaging That Really Works

Published: July 01, 2002, By Stanley Sacharow, Contributing Editor

ACTIVE PACKAGING TECHNOLOGIES
Oxygen Scavenging Water Adsorption
Carbon Dioxide Control
Heat/Cold Insulation
Ethylene Control Time–Temperature
Tags
Anti-Microbial Preservatives

Active packaging has been present as a concept for many years in varying forms, but interest has grown recently thanks to a rash of publicity about the development of newly enhanced oxygen absorbers, antimicrobials, and ethylene absorbers.

Along with this interest have come new perspectives for food packaging, such as the concept of indirect food preservatives from the package into the food.

Active packaging focuses on the development of materials that in some way interact with the product to improve quality, safety, shelf life, and usability.

Much of the initial work on active packaging centered in Japan, where oxygen scavenger sachets were introduced in the late 1970s. These “ageless” iron-based scavengers from Mitsubishi Chemical have been used over the years in many Japanese food packages. While they never have been very popular in the US, there are still many packages on the market using the sachets.

In recent years various films have been developed that utilize iron in the film. Many of these are opaque and are not used widely due to initiation problems.

Another vital area of development has been academia, where many types of active packaging concepts for foods have been introduced. There also have been sporadic projects at film suppliers such as Cryovac Div., Sealed Air, governmental organizations, and research and development labs in Natick, MA, and CSRIO (Australia).

Oxygen Scavengers: Explosive Growth
The rise of oxygen scavengers is evident. With a growth rate estimated at more than 50% annually for beer crowns alone, bottles for other beverages, fruit juices, sport drinks, and case-ready meat also head the list. Other substantial markets include trays and lidding stock for home replacement meals and composite cans.

Projections call for the use of 3 billion packages using oxygen scavengers by 2004 in North America and more than 6 billion worldwide.

Significant activity on the increased use of oxygen scavengers has been seen with PET bottles for beer and other beverages. These have included products such as “Amsorb DFC” from BP Chemical. Targeted for the non-carbonated fruit juice market, the additive is capable of removing oxygen that permeates the side walls of a PET bottle.

In the flexible packaging area, Cryovac, Duncan, SC, introduced a range of “OS” (Oxygen Scavenger) films with a polymer in which the film itself is the oxygen scavenger. These are multilayer films with the polymene scavenger incorporated in the film. The film is initiated by ultraviolet light and is fully transparent. This has been used by Nestlé for its Buitoni fresh pasta packages. Other films are under development by CSRIO, Chevron Phillips (US), and CLP (Israel).

Antimicrobials/Flavor Enhancers
Initially categorized and introduced to a wide audience at an IFT conference in Rekjavik, Iceland, in the late 1980s by Dr. Ted Labuza (Univ. of Minnesota), antimicrobials have long been the subject of widespread academic activity.

However, one notable exception that has come from the industry is “No-Tox AM” inks and coatings from Colorcon, West Point, PA. Utilizing Japanese technology, the inks incorporate silver combined with a non-organic ceramic that allows a continuous controlled release of ionic silver over the specified time. Moisture causes a slow release of the substance, which then causes the resultant antimicrobial surface. The antimicrobial material is utilized in the coating formulation, which acts as a delivery system for the silver ions. These coatings can be applied to a wide variety of flex-pack materials by standard coating methods. Inks also are being developed for various printing applications.

As for antimicrobial and flavor advances from academic circles, along with Labuza's pioneering work have been some recent successes in active packaging by Dr. Joseph Hotchkiss at Cornell. Among these successes has been the development of an enzyme in a film material used to reduce the bitterness in citrus juice. Using naringanase, an enzyne-derived fungus, the material was incorporated in the film liner of a juice carton. Since the bitterness in grapefruits is due primarily to a common plant compound that has sugar molecules attached to it, the enzyme clips off those sugar molecules, making the juice taste sweeter.

In the antimicrobial area, Hotchkiss currently is working with an enzyme called lysozyme, which is most common in a hen's egg white. Lysozyme also occurs in human saliva and tears and is fairly common as an antibacterial enzyme. The material has been successfully incorporated in a film.

Other possible concepts include using a cholesterol-reducing enzyme in a packaging film to reduce the cholesterol content of milk or dusting the inner surface of a film with an antimicrobial powder spray.

Ethylene Gas/Moisture Control
There have been many developments in the area of ethylene gas removal in packaging.

“Orega” film has been developed for preserving fruits and vegetables. The ethylene-absorptive properties work by the addition of a fine porous material such as zlolita or carbon. In addition, CSRIO has introduced a compound that removes ethylene gas, which causes the leaves to turn yellow, from around plants. An organic reagent that reacts with ethylene and diffuses into the package is incorporated into the film.

The diffusion rate largely determines the reaction rate, and the reagent preferably should be included in the more permeable layers of barrier films. Only small quantities are required to remove ethylene at levels of a few parts per million.

In the area of moisture, development has proceeded far past the use of silica gel sachets for various products. There have been attempts to produce desiccant combinations incorporated in the packaging film. Although still fairly blue-sky, this appears to be an area of promising success.

For flex-pack converters, both cost and converting applicability are important factors in the successful use of most active packaging concepts.

Because the technology is so new, it tends to be fairly expensive. A cost-benefit equation as to whether the extension in shelf-life overshadows the increased price would be helpful. However, other factors also need to be considered, including the possibility of quality improvement, distribution changes, and nutritional enhancement. Only then can converters decide how advantageous it would be to include active packaging in their product mix.

NEW STUDY
Pira Intl. has just published “The Future of Active Packaging.” It is a landmark study dedicated to providing a comprehensive understanding of the entire field.

On p. 8 the conclusion states: “The long-term outlook for active packaging is positive in western markets, although the market is set to evolve in a rather different way, with converters seeking to incorporate active packaging ingredients into barrier materials or caps/closures rather than employ loose sachets. Aside from select fresh food, pharmaceuticals, and various specialist industrial areas, the other key application market for oxygen scavengers is likely to be PET-packaged beer, forecast to account for around one-third of all US and around one-quarter of western European oxygen scavenger units by 2007. With PET forecast to account for just 3.5% and 2.3% respectively of US and western European beer sales (including draught beer), there is significant potential for growth for the remainder of the decade and beyond.”

The report, priced at $3,750, also says: “Another major factor in Europe which cannot be overlooked revolves around moves by the European Commission to put in place legislation to formally recognize active packaging and adjust legislation to (probably) relax rules on migration levels from packaging, thus facilitating moves towards the development of preservative release mechanisms and antibacterial films, in addition to other technologies which involve interaction of this nature between packaging and contents. The Actipak project was sponsored by the European Commission to ‘evaluate safety, effectiveness, economic-environmental impact and consumer acceptance of active and intelligent packaging,’ and ended in December 2001 after three years of research. The results from the process will be used as the basis for new legislation, or amendments to current EU food contact and other laws.”

For more information contact Pira, Randalls Rd., Leatherhead, Surrey KT22 7RU, U.K.; +44 (0) 1372-802000; piranet.com.

Stanley Sacharow has been in the flexible packaging industry for more than 35 years. His company, The Packaging Group, is an organizer of targeted conferences and a consultant to the international packaging/converting industry. He is also the author of PFFC's “Package Converting” column. Contact him at 732/636-0885; e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it..