Part 3.1.8: Dehydrated and dry foods

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Drying as a technique for food preservation has been with us since civilisation was born. Yet today it remains a very efficient and widely used way to greatly extend the useful life of foodstuffs. Once safely protected from light and gases, the food retains its nutritional value and texture until re-hydrated.

Removing the water eliminates any support for bacteria and other contamination. It also removes a high proportion of the product weight and space requirements, so saving valuable resources otherwise used in storage and transport.

Aluminium foil can provide the essential barrier needed to completely and reliably stop the ingress of moisture and escape of subtle flavours. It also prevents the UV rays, present in most forms of lighting, from causing the ‘photo-oxidation’ and rancid taste of the fat and oil components of dried food products.

Alufoil, mainly in the form of sachets, is widely used to package such food items as peas, beans, milk and soup powders, cake mixes, sweet and savoury sauces, herbs and spices, yeast, instant beverages such as chocolate and malt-based drinks, tea and coffee. By only using the amount needed, single serve sachets ensure that the rest of the product remains in top condition.

Essential properties

Barrier

Alufoil’s total barrier to light, oxygen, moisture and aromas is the principle reason for its use in the flexible laminates used for dried food products. Valuable aromas are fully retained.

Heat conductivity

Aluminium is very conductive to heat. This can help minimise heat-sealing times for sachets and pouches.

Tough laminates

Strong alufoil laminated pouches withstand the stresses and impacts encountered in the distribution chain. Specially tough laminates can withstand the penetration of sharp particles and deter insects.

Decorative potential

Alufoil’s metallic finish plus compatibility with all printing methods provides designers with scope to create stunning graphic design and shelf presence.

Lightness and space economy

Economies in both transport and storage result from lightness and the flat or reeled format of empty packs.

Sustainability

By incorporating a layer of alufoil into a laminate, a reduction in the weight of other materials can be made. The barrier job is done totally by the alufoil: the other substrates are there for their sealing and structural properties only.

In the case of alufoil single-serve sachets, product spoilage can be greatly reduced. This saves both materials and energy resources. Furthermore, the energy content of alufoil laminates can be recovered by thermal processing after use.

Applications

Pouches and sachets

By far the most popular way of protecting and marketing dried foods is the handy sachet or pouch. These can be made in a variety of sizes and shapes, from the smallest ‘stick pack’ of instant coffee to very large multi-portion packs used by the catering industry for such products as soup and cake mixes.

Savoury sauces and soup powders, cheese and stock cubes

In the savoury foods sector there are usually sensitive but essential ingredients upon which the flavour and food value depend. Dry cheese products such as powdered parmesan, for example, require a strictly controlled but low humidity content for long life coupled with good flavour. Meat, fish and poultry stock cubes, often high in moisture-loving salt, can enjoy the full (and deadfolding) wrapped protection of a non-laminated alufoil wrapper.

Peas, beans, rice, potato crisps and pasta

Dependent upon the fat or oil content, so dry carbohydrate foods need protection from the damaging effect of light. Most dried pulses and rice will keep in good condition without completely light-proof protection, but if the full subtlety of the flavour and aroma is to be preserved, alufoil offers a good packaging choice.

Cake mixes, biscuits and sweet sauces

Many cake mixes, powdered dessert sauces and biscuits are high in sugar, a highly hygroscopic ingredient. The shelf life of high quality biscuits can also suffer if not fully protected from oxygen and moisture. Alufoil laminated pouches and sachets can stop such deterioration.

Hot and cold beverages

Sold in single-serve sachets, drinks such as powdered milk and chocolate, malt-based drinks, instant coffee and tea, can all benefit from the longevity provided by alufoil. The ‘use-by date’ on the packet may often be greatly exceeded once the product is in the kitchen cupboard, but alufoil helps to make sure that the drink can still be fully enjoyed many months later.

Herbs, spices and yeast

Perhaps the best example of alufoil’s protective role is in the packaging of aromatic herbs and spices. Alufoil has been scientifically proven as a complete barrier to the organic molecules which make up flavour and taste. Dried yeast, a ‘living’ organism, will last for very long periods in the total protection from moisture that an alufoil sachet can provide.

Alufoil-lined cartons

For many dry food products, one of the several versions of alufoil lined cartons can combine technical efficiency with great consumer convenience and attractive graphic design.

Powdered food products such as baby milk and drinks such as chocolate and tea etc. can be very effectively presented in foil-lined cartons. Some cylindrical designs offer an easy-open fully protective alufoil membrane under a plastic reclosable lid. Rectangular cartons can be perforated at the top seam for easy opening.