Production residues from sprouts become raw material
The cultivation of Brussels sprouts is inextricably linked to our country. Every year, 63,750 tonnes of Brussels sprouts are produced in Flanders on 2,550 ha of land. After harvesting, some 18 to 25 tonnes of Brussels sprout canes remain per hectare. These are left in the field as soil improvers, or possibly used as animal feed.
With this project, Inagro vzw wants to conduct research into a higher-quality valorisation of the residual flow. In this way, we want to work towards a multifunctional agricultural model in which the farm, in addition to being a food producer, is given a new role as a supplier of raw materials for other industries.
By refining the sprout cabbage canes, we get two streams: fibre and juice. The fibre can serve as an alternative to traditional cellulose fibre in various industries, such as the paper industry. The juice we screen for high-quality bioactive compounds that, after extraction and purification, find application in the oleochemical industry.
By valorising the sprout cabbage canes in this way, we are building bridges between various top sectors in Flanders.
By stably ensiling chopped sprout cabbage canes, we can preserve them for a longer period of time without losing quality.
We screened the juice from the Brussels sprout cabbage canes and discovered high-quality bioactive compounds (glucosinolates, sterols and cellulose) that, after further extraction and purification processes, are applicable in, for instance, the oleochemical industry.
For the fibres from sprouting cabbage canes, we find applications in the paper industry. They have a positive impact on the paper production process: the addition of sprouting cabbage cane fibres improves the paper's tearstrength.
The project was packed with learning lessons and also significantly increased our knowledge about the properties of sprout cabbage canes and processing and stability techniques.
MOST IMPORTANT LESSONS LEARNED
Fossil resources are finite and even with recycling and reuse, there are limits. With rising material prices, interest is growing from various sectors in locally grown, renewable raw materials.
Four-crop valorisation is necessary in agriculture, but with different added values. One sub-stream is needed that provides the highest added value.
Although fibre from sprout cabbage canes proves valuable in paper production, the fraction of canes we obtain is still too small for paper production. Because producing paper requires very large volumes, using non-pure streams seems appropriate.
Setting up a logistics chain requires good cooperation between several players. The challenge is to get the fibres delivered in the right form to the processor. Direct involvement of all stakeholders, including farmers, is very important.
2.700ha sprout sticks in Flanders
150.000tonnes harvestable (fresh)
9.500realistic dry biomass
WHAT DOES THE FUTURE HOLD?
First, we need to conduct further tests with paper. Together, Stora Enso and Tectero are looking at opportunities to scale up the paper production process and conduct initial printing tests.
In addition, there are still missing puzzle pieces in the logistics process and the financial picture also needs tinkering.
Projects like this are a difficult process: no logistics chain will take off if the potential is not known, but in order to know the potential there is still a lot of testing to be done on a small scale. We were already able to take some important steps and achieve nice results on a technical level, but to move to effective implementation, new grants or investments would be a valuable support.
The knowledge gained from this project will already remain available on our website and with the researchers involved. The knowledge on processing and stabilisation techniques will also be included in other research on valorising agro-residuals.