FEATURE FOOD ENGINEERING
The 3D printing of foods – from concept to reality Words by Drs Amy Logan, Peter Watkins and Bhesh Bhandari
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D printing is a form of additive manufacturing, which involves a computer-controlled process of sequential layering to form a predesigned object. This technology is more commonly used for the production of metal and plastic speciality items, however current research to develop suitable food ‘ink’ ingredients has led to the reality of using 3D printing to prepare on-demand foods in kitchens or elsewhere such as in restaurants. With a global value of around $485.5 million in 2020, the market for 3D printed food products is estimated to grow to around $1 billion by 2025, primarily in the confectionery and bakery space.1 Recent advancements have meant that more complex and multi-ingredient food products can be fabricated using 3D printing with customised colour, shape, flavour, texture and nutritional loading. The concept of 4D printing is also emerging, where the structure of the 3D printed food can change with time. For example, the development of flat pasta that will morph into predesigned shapes when rehydrated and exposed to heat,2 providing a novel consumer experience as well as packaging efficiencies for the flat, dry ingredient. Our recent ICEF13 legacy book chapter focuses on the hardware, inks, applications and commercial activities associated with 3D printing of foods
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from which parts of this article have been extracted.3
Hardware Four different types of 3D printing hardware are commonly used for the production of foods based on the principles of: • Material extrusion - where the food ink material is in a liquid or powder form and forced to flow through a shaped hole or die under varied temperatures and pressures at a steady rate to form the desired 3D product. This is the most common method applied to food 3D printing • Material jetting - which uses an array of pneumatic nozzle-jets to produce a layer of the ink material and deposited onto a surface, similar to 2D inkjet printing • Binder jetting - which is similar to material jetting but uses a liquid binder with a powder base to form the desired product • Selective laser sintering - where a laser is used to apply high temperatures and fuse the powder ink materials in layers.
Inks and applications The form (e.g. dried powder or liquid concentrate) and physicochemical properties of the 3D printer inks are important considerations for the construction of different food materials, and the user will need to
match the ink’s characteristics and 3D design parameters to the mechanism of the specific printer hardware. In most common extrusion types of 3D printing, a food ink must be able to flow from the print cartridge, yet form a self-supported shape once deposited on the printing platform. As such, much emphasis has recently been placed on understanding the material properties of food inks with or without the addition of thickeners or stabilisers, and how they respond during the 3D printing process. 3D printing allows for the upscaling of low value products (such as vegetable rejects and meat offcuts) and the introduction of novel ingredients to construct attractive and nutritious food products. Consumer acceptance needs to be considered in the development of 3D printed foods, especially when novel ink ingredient or approaches are considered. A survey of Australian consumers conducted in 2016 suggested little support for cultured meat and insect-based foods.4 However, more recent media attention and growth in the number of emerging start-up companies involving cellular protein and insect farming, indicates a step-change in consumer acceptance, providing greater social licence for advancements in this space. It is fascinating that 3D printing makes it possible to control the
