Packaging trends: Call for convenience

The latest packaging innovations were on show in Cologne last April at Interpack 2005. Ease of use, ‘ready to eat and drink’ and extended shelf life were some of the major trends at the world’s largest packaging fair.
Elsevier Food International, Vol. 8, Number 3, September 2005
Vincent Hentzepeter

In order to meet the growing demand for convenience foods, the packaging industry has developed improved materials that combine airtight seals with smart opening and closing  systems, while protecting packaged products against aroma loss, dehydration and the impact of UV-light. Packaging that can be heated in the microwave offers ultimate convenience in the area of refrigerated fresh foodstuffs. Steaming, rather than cooking, the contents, speeds up preparation times while flavours and vitamin contents are better maintained.

Anti-fog
Most packaging innovations are in the area of fresh convenience foods solutions. There has been progress in extending the shelf life of refrigerated foodstuffs such as ready meals, green salads, meal components, (marinated) meat and chicken and fish. Gas flushing in combination with high-barrier films and airtight trays create a modified atmosphere in which the product can be kept several days longer without dehydration or discolouring problems. Vacuum packaging is even more effective, extending expiration dates up to weeks. However, this process may cause discolouring of, for example, meat and within a compressed pack products do not look very appetising. In this case, a full-colour printed secondary packaging, for instance a sleeve or a carton box depicting a meal suggestion, is needed to create a fresh appearance. For robust products, like poultry, sausages or parmesan cheese, shrink packs that fit like a second skin around the product are a good alternative for so-called vacuum shrink bags. In contrast to shrink bags, no overlapping flaps of the bag obscure the product surface. From an aesthetic point of view, this is a great advantage for premium products.
To keep green salads and vegetables fresh up to a week, laser-perforated films are a promising invention. Micro pores permit the creation of new gas equilibrium within the packaging. This  enables the product to ‘breath’ at a lower metabolic rate, keeping it fresh and alive longer.
Condensation of the pouch can be prevented using packaging material with anti-fog properties. Because of the modified surface tension of the film, droplets no longer spread evenly over the foil, but tend to concentrate in pockets. An excellent visibility of the contents throughout the storage time is the result.

Home cooked

Microwaveable soup from Heinz served polypropylene cup. Heat-andeat is motto.

Microwave steam packaging is a new hype in the fresh food sector. Examples are trays with raw fish filet plus sauce, uncooked mixed vegetables andfresh ravioli with basil leaves and grated Italian cheese. Although this principle can also be applied to speed up the heating of frozen and ambient products, the benefits of steaming raw or semi-processed products go beyond convenience. As steam cooking raises temperatures above boiling point, products require shorter cooking times, thus better preserving minerals and vitamins and optimally containing flavour and colour. What is more, producers can fill the package with uncooked ingredients, offering the freshest product possible. For consumers this creates a feeling of like rice, soups and pasta meals with a shelf life between six and 12 months, Mondi Packaging has developed the Neo-Steam stand-up pouch.
An integrated valve at the top of the packaging opens gradually once pressure reaches a critical point. The absence of sudden drops in pressure prevents a product like soup from squirting out of the pack and spilling into the microwave.
Flexible can Many convenience products are sold under ambient conditions. Here tin cans are still dominant. However, as canned products are generally not associated with quality or freshness, food producers look for alternatives. Stand-up pouches are a possible candidate but have some disadvantages. Due to their conical shape, they cannot be stacked efficiently. They also demand more shelf space per unit than cans or jars. On the other hand, flexible packaging like the pouch is well suited for microwave heating. With this in mind Luc Fevrier, category manager Preserved Products at home cooking.
There are currently several steam systems on the market. Huhtamaki’s Steam Chef consists of  a tray in which either fresh, (un)cooked or frozen meals and ingredients are prepared in their own water molecules. Once pressure gets too high, excess steam is released through a self-venting anti-fog film. With this solution, puncturing the lid before cooking is a thing of the past. The ‘Cook’in sap’ principle of Saint-André Plastique is based on anti-fog films with a programmed automatic opening process. Raw vegetables and potatoes are cooked al dente in special bags for five to seven minutes at 900 Watt. If necessary, water pads are added to produce enough steam. For ambient products like rice, soups and pasta meals with a shelf life between six and 12 months, Mondi Packaging has developed the Neo-Steam stand-up pouch. An integrated valve at the top of the packaging opens gradually once pressure reaches a critical point. The absence of sudden drops in pressure prevents a product like soup from squirting out of the pack and spilling into the microwave.

Flexible can
Many convenience products are sold under ambient conditions. Here tin cans are still dominant. However, as canned products are generally not associated with quality or freshness, food producers look for alternatives. Stand-up pouches are a possible candidate but have some

The Zipper bag with Slider technology allows opening and closing with a gentle movement of hand.

disadvantages. Due to their conical shape, they cannot be stacked efficiently. They also demand more shelf space per unit than cans or jars. On the other hand, flexible packaging like the pouch is well suited for microwave heating. With this in mind Luc Fevrier, category manager Preserved Products at Carrefour France, launched an idea for a volume-saving multi-layer, polypropylene pack for processed vegetables. The British packaging firm RPC Bebo UK developed a transparent tray with two or four individual portions that can be retorted and be kept on an ambient shelf for up to two years. Strong point of the ‘Conserves Pratiques’ range is that the separable compartments can be reheated in the microwave easily and quickly. The packs are sold in a brilliantly printed cardboard outer sleeve with pictograms that provide instructions to the consumer.
Another substitute for cans is the carton pack from Tetra Pak. Bonduelle Italy was the first company to use this solution two years ago. Tetra recart has a cubic shape and withstands lengthy contact with hot water and steam connected with the retort process. Any product, from salmon to meat, beans and whole vegetables, can be filled in this 400-gram package that because of its light weight and square shape may reduce distribution cost by tens of per cents.

Feel good peel
Peelable packaging solutions and airtight seals are at odds with one another in terms of product protection. Easy opening features naturally weaken the (seal) construction. Therefore, a compromise must be found. This delicate balance can be influenced in favour of the customer by applying improved polymer constructions and smart design or a combination of both. For a better control of the seal and peeling properties of flexible plastic packaging, DuPont Packaging developed the Lock&Peel technology. At the core of this concept is a special grade of the widely used seal medium ‘Surlyn’. This resin delivers, depending on the selected seal temperature and other conversion parameters, either a tight, hermetic ‘lock’ seal or a well manageable, ‘easy-to open’ peel solution. One advantage is that converters with this flexible solution are able to meet individual brand requirements with one multifunctional peel system. Equally important is that Lock&Peel, according to DuPont, hardly deteriorates over time. Even after long storage periods, there is minimal increase in peel strength. Peelable seals do not become permanent ones as can happen with some sealing compounds. The latter is a critical factor. The quality of a seal and the way it opens influence the overall quality perception by the consumer. Peel systems that are difficult to open cause negative product associations.

Open & close

Fit Shrink Packaging from Multivac fits like a second skin around premium products.

An example of user-friendly design and upgraded thermoforming technology is the re-closable Aroma Box that German packaging specialist Multivac developed with meat manufacturer Wolfertschwenden. A customised, torsion-resistant lid engages the transparent tray with an audible click. As the lid is almost impossible to bend or damage, the packaging can be closed again tightly even when it has been opened frequently. Moreover, the pack preserves the taste and freshness of the packaged product after it has been opened for the first time. Ambient smells are kept out to prevent these affecting the meat products. A film that includes an oxygen barrier provides aroma protection and can also be printed all over to suit a high-quality brand positioning. Zips are by far the most consumer-friendly solutions to close pouches or bags after opening. In contrast to adhesive tapes, which are stuck to the package after folding the foil, zips do not lose strength or suffer from wear, dust and humidity. They also prevent pouches and bags with frozen products from spoiling the freezer, once opened. After breaking the permanent seal by tearing off a perforation strip, the package can easily be zipped open. Zip-Pak, supplier of 200 patented zipper profiles, has developed several innovative closures for ‘difficult’ products and specialities from shredded cheese to pet food for small and large format pouches. New products are a hightemperature resistant  retortable and a powder proof zip.
Ease in use is provided by the Slider technology (see picture) that reduces opening and closing to a sliding movement of the hand.

Glass coating
PET has proved to be the shooting star in the beverage market. After carbonated drinks, dairy and juices are increasingly filled in this light and unbreakable material. The trend towards on-the go consumption has given an enormous impulse to consumption of beverages like lemonades, mineral water and sport drinks in half litre or smaller bottles. The beer market, with a strong glass tradition, has now also discovered the merits of PET. One of the constraints here is that most beer containers are sold in a volume range between 0.3 and 0.5 litre. As beer is a highly sensitive product and PET has rather poor gas barrier properties, product degradation by carbon oxide leakage and oxygen introduction through the bottle wall is a threat.
This is especially true for small bottles, as they have a relatively high packaging surface when their content is compared to 1.5- to 2-litre bottles that are commonly used for soft drinks and mineral water. Fortunately, the application of high barrier layers or multi-layering solutions can enhance the barrier properties of PET to an acceptable level. By plasma coating the inner surface of a PET bottle with a very thin, clear layer of silicon oxide, PET gains more glass-like properties. More or less the same can be achieved using carbon. Gas transmission rates can also significantly be  lowered if a bottle is constructed from PET in- and outside layers and a more or less impermeable material in the middle. Single-serve beer portions in upgraded PET bottles may be stored up to a year without noticeable off-flavour problems. The maximum would be several months in standards bottles.

Oxygen scavenger
The risk of oxygen degradation in PET bottles can be further reduced using closures with oxygen scavengers. These contain an active material, for example sodium sulphide, that neutralises any residual oxygen that remains in the top space after filling or enters the bottle during storage. In combination with coated or multi-layered PETbottles, maximum protection can be offered to beer, as well as functional drinks. The latter often contain ingredients like vitamins and complex organic compounds or probiotics that are sensitive to oxygen, especially when exposed to UV light. As these health products are premium priced and the functional foods market is expected to boost in the next few years, a bright future lies ahead for advanced PET packaging, including innovative closure systems.