Cleaner Technology Projects in Denmark 1997
Examination of the Connection Between Varieties of Beets and the Amount of Cleaning
Undersøgelse af sammenhængen mellem roesorter og jordvedhæng
Arbejdsrapport nr. 42, 1997, Miljøstyrelsen
Danisco Sugar, Development Center Nakskov started in 1993 a project called "Rene Roer" (clean beets) which purpose was to ensure that the sugar beets were brought to the factories as clean as possible, and if possible so clean that further cleaning at the factory would be unnecessary. The purpose of this project is to point out the specie of beets, which has the best outer quality when it comes to the most optimal cleaning. Furthermore there is a wish to develop a method to measure the cleaning of the beets so that the choice of beets based on this criterion will be as objective as possible.
For the 1996 campaign at the locality Kristianssæde, Danisco Seed had sown 11 varieties of beet in test fields with approx. 150 beets each. Danisco Seed selected the varieties, and commercial sugar beets and fodder beets as well as non-commercial varieties were chosen for the experiments. During the weeks 40, 41, and 48 DC harvested the beets by hand, using a beet fork, and DC made various investigations on the external quality of the beets (cleanability, dimensions, shape, and location in the ground). During large parts of the harvesting periods the conditions were very moist, and this resulted in beets with a high amount of adherent soil. This resulted in a change of procedure in the fields, and the soil was beaten off the beets (dropping from approx. 1.5 m).
The locations of the beets in the ground were measured, leaves were cut off at the bottom of the stem, and each individual beet was marked in order to be able to follow it all the way through the cleaning process. Typically 5 beets per variety per day were treated.
At DC the following procedure took place:
 | Measurement of leaf attachment diameter. |
| Cleaning of the beets individually (with variations; but always with cleaning in modules with brushes as the main cleaning) |
| Final cleaning by compressed air pistol |
| Cutting off crowns and measurements of crown diameter and beet. |
| The cleaning results are expressed as the percentage of residue soil in clean beets without crowns. |
The results were:
| Of the 11 varieties investigated, the "football" beet and especially the "cylinder" beet differ markedly from the others as regards to shape and location in the ground. The cylinder beet has a "soil-repellent" form due to a high location in the ground, an outward arched shape from top to tail, small root grooves and root hairs mainly attached to the tail. |
| Also, as regards cleanability, the cylinder beet differs positively from the others, because its shape gives good conditions for a low content of adherent soil, and it facilitates the cleaning conditions. |
| Generally, the commercial varieties do not differ much as regards cleanability in the range of 0-200% starting soil. Final soil is generally proportional to starting soil. |
| Differences between clean-ability for fresh beets and beets stored for 1-2 days could not be detected. |
| The method used to measure cleanability, where beets are cleaned with brushes, is not yet optimised for all conditions (high/low soil tare and wet/dry soil), and the method must be further developed. |
The conclusions were:
| Of the 11 varieties investigated, the cylinder beet has the most optimal shape as regards cleaning. |
| The optimal method for evaluation of the cleanability has not been found. The applied method with brushes gives a rough estimate of the importance of the shape of the beet, but the method is influenced by soil - and harvesting conditions. |
| The rough method should be supplemented with a method, which expresses the cleanability in the low range of soil tare (0-5% initial soil and < 1 % residual soil after cleaning). Cleaning by compressed air on a single-beet level in a newly developed pilot plant would be a possible method (to be investigated in 1997). |
Author/ institution
Bjarne Fallesen, Flemming Hansen og Franck B. Hansen, Danisco Sugar
This report is subsidised by the National Council for Recycling and Cleaner Technology
ISSN no. 0908-9195
ISBN no. 87-7810-796-2