Nature, cultivation and processing of sugar beet: multiple facets!

Nature cultivation and processing of sugar beet multiple facets

This article is part of a series of publications in which Futura, in association with the Interprofessional Association of Beet and Sugar (AIBS), follows the beet season. With the harvest season in full swing, it’s time to wonder what will become of the beet plants that grow for almost a year. Beet cultivation is the beginning of a long process that will give rise to finished products, many of which are unexpected.

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The harvest of the sugar beet has just ended with a return to “normal” for production, after a terrible year 2020 ravaged by the virus of the jaundice ! After sowing the beet seeds in March-April and having pampered the young shoots for months, it is time for the “betavier.es” to harvest the precious roots from which the beetroot will be extracted. sugar long-awaited in the form of sucrose. The uprooting of the roots begins in September and lasts until December and is followed by several treatment processes in the factories which allow France to be today the second largest producer of beet sugar in the world. In 2020-2021, France produced around 3.4 million tonnes of beet sugar and was only surpassed in Europe by Germany, which produced around 4,100 during the same period. . France also posted a beet sugar yield in 2020-2021 of 9.4 tonnes/ha, i.e. about twice as much as fifty years ago.

The French sector is established in the North (from Pas-de-Calais to Loiret) and in the East (as far as Bas-Rhin) of France. It is complementary to the sugar cane sector, which is developed in the overseas departments (Guadeloupe, Martinique and La Réunion) and between them, these French sectors make the country the leading European sugar producer.

Beetroot, did you say beetroot?

The sugar beet should not be confused with its cousin, the fodder beet. The first presents a white conical root which develops entirely in the ground and which contains between 15% and 20% of sugar approximately. The second has more varied shapes, its root can indeed be white, orange or red and conical in shape but also oval or round. Its sugar content is lower than that of sugar beet because it is between 5% and 10%.

Sugar… or rather sugars

Sugar is a component of many foods and everyday products. It is used, for example, in artisanal pastries or in pre-packaged biscuits, in sugary drinks, powders for breakfasts, yogurts, desserts, fruit preserves or simply as table sugar. It also enters and in a less intuitive way in the composition of pharmaceutical products such as syrups and tablets. From a nutritional point of view, sugar is part of the family of carbohydrates which are classified according to their composition. Simple carbohydrates, such as fructosethe glucose and the galactose consist of one or two molecules, this is for example the case of sucrose which is composed of a glucose and a fructose. These simple carbohydrates are naturally present in fruits, vegetables and milk or are added a posteriori in food. They are indicated in the “including sugars” line of the nutritional tables. Complex carbohydrates are made up of long chains of glucose, such asstarch which is in the starches such as bread, pasta and rice.

The main form of sugar found in sugar beet, just as in sugar cane is sucrose and consists of a glucose and a fructose. The sugar extracted from sugar beet is contained in the conical, white root of each plant. It constitutes the energy reserves that the plant accumulates during the first year of its life, in order to reproduce the following year. It is therefore necessary to uproot the plants before they enter the reproductive phase and use the sugar they contain in order to multiply.

From beet cultivation to the sugar cube

Once the sugar beets are full of sugar, they are torn from the fields and then washed and cut into thin strips called cossettes. The latter are bathed at 70°C in water, which allows them to render their sugar through a process of diffusion. The sugary juice is then filtered in order to remove the foam and then concentrated by evaporation so that the filtrate initially containing 13% sugar eventually reaches 70%. Small pieces of sugar are then added to the previous mixture so that the sugar in the mixture liquid agglomerate there and cause these crystals to grow. This crystallization stage is followed by centrifugation in order to separate the sugar from the molasses (dark brown or black residual syrup which cannot be crystallized) then by a stage of hot drying of the sugar crystals.

Once dry, the crystals are packaged, in their raw form with regard to powdered sugar or in the form of squares thanks to a humidification and a molding step. It takes about a kilogram beets to produce 150 grams of sugar and it takes on average one sugar beet to produce 25 sugar cubes.

Everything is good in beets

Besides sugar, sugar beet is the matter premiere of many other products, such as thealcohol for hydroalcoholic gels, cosmetics, perfumes, or bioethanol fuel. For example, sugar residues enter a process of fermentation then distillation to produce bioethanol. This liquid fuel is then incorporated into gasoline and used in gasoline-type engines. There is up to 10% bioethanol in Sans Lead 95-E10 and between 60% and 85% in Superethanol-E85.

This fuel, Superethanol-E85, reduces the emissions of CO2 and 90% those of fine particles compared to gasoline. It is also the fuel of purchasing power, thanks to its average price of €0.76/l. It thus saves more than €500 for 13,000 km travelled, including an overconsumption of 25% compared to petrol.

Article produced in partnership with AIBS

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