Beware the brazil nut effect

The production and packing of sweets and snacks presents new challenges to machines and their constructors as market demands increase. In particular, the processing of nuts and cereals for sweets and snacks is treading new paths in the handling of these sensitive, free-flowing materials.

Over 300 companies will be presenting techniques and solutions for the sweets and snacks industry at the ProSweets Cologne 2016 international supplier fair. From 31 January to 3 February 2016, ProSweets Cologne will offer comprehensive information and a direct line to suppliers of techniques, machinery and technology.

The path taken by a cereal flake during the production of muesli shouldn't be underestimated, and sweet and snack manufacturers have plenty of tales to tell. The flow behaviour and transport characteristics of nuts, pistachios, chocolate crispies or dried fruit are very difficult to predict in advance. Elaborate test series of varying degrees nearly always precede the implementation of mixers, driers or other systems for handling the free-flowing goods.

Mixtures that include particles of differing sizes, weight and densities prove to be particularly tricky. Some of the physical phenomenon can actually be observed at the breakfast table. If one pours muesli out of a packet, the big nuts always land on top. The reason: while pouring, hollow spaces form under the larger particles. Smaller particles flow into these hollows and thus move further and further down in the mixture. The phenomenon that is referred to as the ‘brazil nut effect’ causes technologists considerable headaches because the prerequisite for sweets of high quality is the exact adherence to the recipes.

Segregation-free on the way to becoming a muesli bar

They are a first choice for between-meal hunger: sweet bars filled with cereals and pieces of fruit. Often the granular ingredients have to be carefully heated during the mixing process so that the liquid chocolate can flow into the spaces between the granular ingredients when the chocolate coating is finally applied. Hence, there is the optimal mixer for almost every application.

Volumetric plate metering devices ensure the exact supply of cereals, dried fruit and nuts in the Conbar bar manufacturing systems of Sollich. It not only enables rectangular-shaped products to be produced, but also bars with different cross-sections. The SnackFix by Hosokawa-Bepex is an easy way for manufacturers to get started in the automatic bar production sector, with a system for the production of fruit bars consisting of just two components. The cereals are continually mixed with the binding agent in the processing unit. After the mixing process, the mass is moulded into an endless carpet by two calibrating rollers and cut into the desired product width.

A coat for crunchy granules

Crisps lend chocolate and bakery products a crunchy effect and produce interesting colour effects in ice-cream. However, the crunchy granules obtain their characteristic properties after the coating process, where the cereal extrudate is coated with a layer of chocolate, yoghurt cream, caramel or fruit mass. The coating protects the crisps and retains their crunchiness in the end product. Fluidised bed systems or coating drums are the appropriate equipment for the coating process.

Predominantly, the size of the particle to be coated is decisive for the choice of process. Whereas for particle sizes under 1 mm, fluidised bed systems are the standard choice, coating drums are used for larger products. So that the crisps don’t stick together, liquid nitrogen is conducted directly onto the product bed. The cryogenic gas allows the applied mass to crystallise evenly.

Packed in small target weights

Whether pure or as a fruit and nut mix, cashew nuts, crisps and dried fruit are packed inside bags, plastic cups or in cans. When six or more components are mixed together, modern multiple-head scales ensure the desired mixing ratio.

Suitable for small target weights, the solutions by Ishida, Multipond and Yamato that are being exhibited at ProSweets Cologne can also accurately weigh oily or fragile products. The multiple-head scales work using the part quantity weighing principle, feeding the materials to the weighing pans that are arranged in pairs. The computer chooses the combination from these that is closest to the filling weight. An additional ring of booster pans enables the intermediate storage of part quantities already weighed. A sophisticated vibration control ensures a uniform product flow.

Whether to improve the recipe, for the introduction of a new product or if the packing format is altered, the right equipment is decisive when processing free-flowing goods. At ProSweets Cologne the focus is on processing and packing systems, which enable fast retrofitting and easy cleaning, allowing manufacturers to keep pace with market demand.

‘Power Nuts & Cereals’

Companies whose product portfolios include nuts, seeds, cereals or grain will be presenting at the ‘Power Nuts & Cereals’ special event. In addition to various types of nuts and almonds, the product range also includes the super food ingredients quinoa and chia.

This theme will also be included in lectures presented during the supporting program. The ‘Speakers’ Corner’ is the location for this: in the midst of the trade fair action, expert speakers will highlight new product trends and their impact on the manufacturing processes.

Held in conjunction with ISM, the international fair for sweets and snacks, ProSweets Cologne will cover the entire value chain in the production of sweets and snacks.