From compost to cakes: Carrot pulp flour gives healthy reformulation green credentials
As part of an innovation pilot course at the Danish Technical University (DTU), wholesaler Greens Engros challenged engineering students to develop ways to optimise its production line and upcycle the carrot peel and pulp.
Through its in-house juicing and fresh-cut produce operations, Greens generates around 100 tonnes of biological waste every month. Although this by-product is turned into biogas or compost, it could have higher value uses.
The success of the project, however, means that it has a new product in its portfolio and hopes to commercialise the carrot flour within one year, turning an expense into a source of revenue.
By replacing 35% flour with the carrot powder, DTU students created a golden coloured bread with a texture and structure that was similar to conventional bread.
According to Timothy John Hobley, associate professor at DTU's National Food Institute who oversaw the project, the taste was “quite neutral with a hint of carrot” that was “quite nice”.
In addition to bread and baked goods, other possible applications include a plant-based inclusion in meat alternatives, he added.
Between carrot peel, pulp and the tips which are trimmed, an estimated 26% of the carrot is peeled before being used in a food product. This means that over one quarter of the vegetable, which is packed not just with fibre but other nutrients such as beta-carotene, is usually thrown away.
According to 2016 figures from EU directorate-general Eurostat, 5.6 million tonnes of carrots are produced in the EU each year.
“If […] we assume all of these carrots are peeled and the ends cut off at least by someone before they are eaten – either by a consumer or in a food production process, then there is potentially 1.4 million tonnes per year of this material. Naturally, not all is accessible to make into flour or other food products, but I think you can see that there is a lot of potential,” Hobley told FoodNavigator.
Together, Poland and the UK accounted for over a quarter of carrot production in 2016, producing 14.7 % and 12.9 % of the bloc’s carrot output respectively, according to Eurostat.
“The prototype was made simply by collecting the carrot pulp, draining out excess water, drying at 65oC, then grinding to a powder. In a full-scale process, this will be done by harvesting the excess heat produced from the cooling system of the fridge and freezer rooms at Greens. Right now, all this heat just goes to the atmosphere.”
This means that Greens will be able to heat and dry the carrot pulp “almost for free”, Holby said.
The project did not calculate the cost of the fibre-packed carrot flour compared to other dietary fibres but Hobley estimates that, since carrot pulp has a negative value as manufacturers must pay to remove it and that Greens will use captured waste heat, the price should be “more than competitive”.
The researchers believe the same process could be used with other fruit and vegetable pulps, such as onion and broccoli.
Chief operating officer (COO) at Greens Lars-Erik Rasmussen said the project with DTU has "increased focus on innovation within the company [and] increased employee motivation".