Chocolate is commonly used to test whether food has been tainted by its packaging

By Jenny Eagle

- Last updated on GMT

Picture credit: Petra Berggren.
Picture credit: Petra Berggren.

Related tags Food contact materials Olfaction

Preserving the quality and freshness of edible products and protecting them from heat, light and oxygen put heavy demands on packaging.

Packaging should also preserve the taste and odour of foods so consumers get what they are expecting every time. Achieving all of this is a complicated task that requires a combination of chemical and human sensory analyses.

Chocolate absorbs volatile compounds easily

At Iggesund’s Laboratory for Sensory and Chemical Analyses in Iggesund, Sweden, a sensory team works with an external panel of 40 experts who are trained to determine whether food and other goods have been tainted by their packaging.

A chemical analysis is then conduced in the laboratory to determine the source of any tainting and to rectify the problem.

Chocolate is commonly used on the testing table​,” said Sara Jonsson, development engineer, Iggesund’s Laboratory for Sensory and Chemical Analyses.

The chocolate is placed in a jar together with paperboard so that volatile compounds from the paperboard can be absorbed to see if he chocolate changes flavour.

Chocolate is convenient to use and rather fat, so it absorbs volatile compounds easily​,” she added.

Migration and flavour scalping should be avoided as much as possible. In migration, odours and flavours from the packaging material are transferred to the product in the package.

Flavour scalping occurs when flavours from a product are transferred to the packaging material.

Packaging is there to protect the foodstuffs and maintain flavours​,” said Jonsson.

“If necessary, you can use a barrier with the paperboard such as aluminium foil to restrict the flavour loss.”

It’s all right for packaging to have a slight odour

Her colleague, chemist, Torgny Ljungberg, said it’s all right for packaging to have a slight odour, as long as it doesn’t influence the flavour of the contents.

If it smells strange, however, it makes you suspicious and more negative towards the product​," he said.

The first thing you do when you open a package is to sniff, and if something from the printing ink or varnish gives off an unpleasant smell, then you won’t want whatever is in the package​.”

Jonsson and Ljungberg.

Ljungberg said such was the case when a German chocolate producer switched to a package that released a smell of varnish.

The varnish was not interacting with the chocolate or compromising it in any way, but the company lost customers due to this odour​,” he added.

Today, most producers of sensitive foodstuffs know which varnishes, inks and glues to avoid, he said. There are also strict regulations regarding what can be used from a health and safety standpoint.

National legislation states which chemicals are allowed in packaging that is in direct contact with food.

If you want to be on the safe side, it’s best to use virgin fibre paperboard, but there are ways to use barriers to avoid the transfer of volatiles in packagin​g,” said Ljungberg.

Virgin fibre

Board made from virgin fibre is suitable for packaging of sensitive foodstuffs because it is clean, stable, and has good printability and convertibility so it can both promote and protect its contents, said Edvin Thurfjell, product manager, Graphics and Packaging, Invercote.


Rules & Regulations

  • In the EU, food contact materials and articles must comply with Regulation 1935/2004 of the European Parliament. According to this, food contact materials under normal and foreseeable conditions of use may not transfer their components to food in quantities that could endanger human health, cause unacceptable change to the composition or deteriorate the organoleptic characteristics of the food.
  • In the absence of harmonised legislation for paper and paperboard, products have to fulfil relevant requirements in the countries where the products are sold.

Tint, odour and microbial contamination are as minimal as we can make it, and these properties are stable over time. This is something you wouldn’t achieve with non-virgin fibres,​” he added.

In addition to health and safety features, consumers want consistency. “When you buy a special brand, you want that brand to always taste the same from one year to the next,” said Ljungberg.

In the 1980s we tried to convince a chocolate manufacturer in England to use our board rather than his recycled board, which interacted more with the flavour.

"They refused to switch, saying; ‘Our customers expect our chocolate to have a board flavour​.’”

It’s best not to underestimate consumer expectations, added Ljungberg.

“Milk in a carton doesn’t taste like milk directly from the cow. It has a bit of a carton flavour, but this is what we are used to and have come to expect,” he said. “We don’t like the taste of fresh milk from cows​.

So before making a packaging change for food, carefully weigh every aspect of how the paperboard and products will interact with each other​.”

Source: Cari Simmons, inspire magazine, Iggesund Paperboard, Issue 52, 2016

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