Customised chocolate Synchronised and multiscaled 3D printing process in food production

3D printing is attracting growing interest in the food industry. It opens up new opportunities, such as making customised products with specific texture and alternating compositions. Nevertheless, major challenges must first be overcome before the technology can be successfully established on a large scale in industry. In particular, production rates must be improved, food mixtures compatible with printing developed and rigorous hygiene requirements met.

Funded by BRIDGE – a joint programme of the SNSF and Innosuisse – BFH, in collaboration with ETH Zurich, is developing technologies for rapid and industry-compatible additive production of structurally differentiated foods.

Chocolate confectionery was selected as the first area of application. A new production process aims to enable the amount of expensive aromatic substances or 5 nutritionally undesirable sugar to be reduced without detracting from consumers’ perception of sweetness.

Harnessing the potential of 3D printing to optimise food products requires in-depth understanding of how taste sensations are created. The tongue plays a key role. In addition to its kinaesthetic function (perception of movement) and the perception of material characteristics, it can also discern taste qualities (sweet, bitter, sour, salty and umami). This sensory capability is based on the interaction of various taste receptors which transfer the signals registered to higher brain regions via nerve pathways.

Initial consumer testing indicates that the perception of sweetness increases when the taste receptors are highly stimulated with alternating instead of consistent intensity. The targeted positioning of the sweetener in the 3D printing process enables the amount of sweetness to be reduced without the chocolate being perceived as less sweet.

A hybrid 3D printing method was selected for the production of chocolate optimised in this way to combine the various components. A chocolate mixture serves as the basic element of the product. Using a procedure developed in-house, it is pressed into the required form – which remains stable – through a nozzle.

After the basic element has been put onto a conveyor belt, synchronised robots manufacture the chocolate based on a digital model. A robot fitted with a dosing pump adds a frothed mixture made of cocoa butter to the chocolate form. This gives the product extra taste and texture. A second robot with micro-jets applies additional aromatic substances and sweetener to the product in line with the required positioning specifications.

The major benefit of this process is the high degree of flexibility in terms of product configuration. Both the geometry and basic form, as well as the structure and positioning of the frothed cocoa butter and aromatic substances can be quickly modified. This means the chocolate can be adapted to the taste and nutritional requirements of consumers at any time and without significant operational disruption on a single production line. The synchronised approach in combination with the extruded basic element also accelerates production speed compared with conventional 3D printing.