Personalised 3D-printed protein bars: Consistency tested by athletes
Personalised. Rich in protein. Printed.
This summer, 51 users of a fitness centre in East Jutland were able to try out a completely new type of protein bars, which were 3D printed on site.
The bars are part of the 3DPERFIT project, which over the past two years has been investigating how 3D printing can be incorporated in the nutrition of gym users and top athletes who follow a diet with a very specific protein, carbohydrate, and fat content.
The project is a collaboration between the Danish Technological Institute, the 3D printer manufacturer Natural Machines, and Linus Pro Nutrition, and there is one challenge in particular that has been central to the project.
Hitting a bar mass that is both print-friendly and offers the desired high protein content.
“The biggest challenge has, of course, been consistency,” says business manager Maja Krogsøe Skou from the Danish Technological Institute, which is a contributor to the 3D print project.
Different sizes of nozzles were tested in the project, since the sharpness of the protein mass increases as the size of the nozzle decreases. However, the printing time increases as well. Illustration: Teknologisk Institut.
Users could use an app to choose between different flavours and nutritional compositions of the protein bars. Illustration: Teknologisk Institut.
A model has not yet been found that ensures that the protein bars can be retrieved without assistance. Illustration: Teknologisk Institut.
The bars are made out of dry ingredients such as crushed hazelnuts, industrially produced branched-chain amino acids (BCAAs), and proteins from whey and soy.
If the mixture is to come out of a nozzle as anything other than a large, deformed, and not-so-appetizing blob, the size of the nozzle must be small enough to be able to print sharp details. This places demands on the bar mass, which must at the same time be soft enough to be able to come out of the nozzle, but conversely firm enough so that the print can hold its shape.
“Our bars are somewhat softer than traditional protein bars,” Maja Krogsøe Skou says and explains that the test subjects did not find that the high protein content makes the bar feel dry—quite the opposite.
“50 percent of the respondents think that the consistency is suitable. The others think it’s too soft.”
No thanks to chewy bars
So, there is still something to work on if the preferences of the East Jutland gym goers are representative of the average fitness centre member.
According to Maja Krogsøe Skou, a lot of work has already been done on the consistency of the bars, which have a protein content of up to 36 percent.
“We had to be very sure of how to handle the ingredients so that the proteins retain their functionality and the starch doesn’t stick too much,” she says.
“For example, we have added hazelnuts to improve both flavour and texture, as they break up the protein structure and make the bar less chewy.”
At the same time, there have been experiments with different protein sources, for example exclusively vegan ones. But the product simply differed too much from what one associates with a protein bar.
App provides many options
Expectations also need to be slightly adjusted in relation to a classic bar wrapped in shiny foil.
In contrast to prefabricated protein bars, which can be bought from vending machines or at the counter in many Danish gyms, the 3DPERFIT bars are neither dried nor baked.
3DPERFIT—3D printing food products for Personalised Sport Nutrition—is a project developed in collaboration between the Danish Technological Institute, the 3D printer manufacturer Natural Machines, and the ingredient developer Linus Pro Nutrition.
The project spans two years and will be completed in October 2023.
During the project, the parties have developed recipes for protein bars that consist of up to 36 percent protein in three different flavours: caramel, cookie, and chocolate.
The bars are printed with Natural Machines’ printer Foodini, which uses cartridges with ingredients such as protein and fats.
Alongside the bars, the project partners have developed an app from which users can order personalised protein bars.
The project is supported by the Innovation Fund and Eurostars.
In order to handle the soft mass, they are therefore printed on a moulded plate of chocolate, which serves as a kind of edible plate on which the protein mass can be printed.
The advantage of this is that the contents of the mass can be put together according to the individual athlete’s needs, and the bar can be ready for pick up in the printer around five minutes after an order has been placed.
“As part of the project, we have developed an app from which you can place your order. Here you can indicate personal preferences if you, as a high-level athlete, know your nutritional needs. Alternatively, you can indicate your type of training and get suggestions for protein bars based on that,” Maja Krogsøe Skou says.
The app has not yet been finished, but the respondents in the user survey think the idea of using an app makes sense.
“The users were really positive in relation to the question of choosing a printed bar over a commercial one. 80 per cent of the respondents indicate that they would to some extent choose the printed bar over a commercial bar, based on the tested concept,” Maja Krogsøe Skou says.
Wide distribution
The hope is, according to the business manager from the Danish Technological Institute, that other user groups than top athletes and gym users will be just as positive.
When Ingeniøren asked whether there were no other target groups that find personalised nutrition important, Maja Krogsøe Skou points out that the project’s results have the potential to be used in many other areas.
“We previously had a project involving 3D-printed food in hospitals, and a protein bar can easily be used there or in similar institutions,” she says, citing military bases as another example.
“The project was initially about investigating whether we can print a protein bar, and yes, we can. Now we can start looking at which challenges that can help solve.”
