Oh sweet! Dissecting the healthy and sustainable potential of the sugar beet

Sugar beets have been cultivated in the rich soil of the TopDutch region since the end of the 19th century. They are then processed into refined sugar, and that is still done in the Northern Netherlands beet sugar factory in Hoogkerk. This factory - the largest in Europe - makes the product that used to be the only product from sugar beets - granulated sugar.

These days, sugar-beet fields can still be seen throughout the TopDutch region. However, granulated sugar is no longer the only product made from the beets. Innovation has made sugar beets suitable for a whole range of different product lines, said Bram Fetter, Operations Director of Suiker Unie, a subsidiary of the AgriFood group Royal Cosun. Suiker Unie is in the top five of European beet-sugar producers. Up until 2017, Mr. Fetter was responsible for the production facility in Vierverlaten, near the city of Groningen.

Sugar beet is still a common crop in the TopDutch region, and its acreage has actually increased since 2015. In 2018, the Netherlands entered the top five producers, measured in hectares of agricultural land, following France, Germany and the UK. The background of this increase was the abolition of European quota on sugar-beet production in 2017. Bram Fetter says that Suiker Unie increased the capacity of its Dutch factories by 20% in that same year. ‘These days the production of sugar is a free market, a global market even.’ For Suiker Unie, Europe is still the most important sales market, but the world beckons, particularly now sugar beets increasingly produce other products.’

The production process is acquiring a more bio-based form, explained Bram Fetter. ‘When sugar beets arrive in the factory they are washed and sliced into thin chips. Warm water opens the cell wall of the chips and the sugar ends up in the solution. The juice is pressed. The beet pulp that remains serves as a source of silage or feed and for the production of green gas. The fiber in the beet pulp is also used to make ingredients for the soap and paint industry.’

The beet juice is purified with lime, heated and evaporated. Bram Fetter continued ‘That requires a lot of energy. So we invested heavily in an energy-efficient evaporation method, and that has halved the energy consumption. We crystallize the thickened juice and capture syrup after centrifugation.’ This syrup then goes through the same process again, to ensure maximum sugar extraction. ‘In the end, molasses remains, which is full of concentrated minerals and salts. That is used by the food industry and the fermentation industry, where it is used to produce yeast. By modifying the process, Suiker Unie has saved more than 50% on energy since 1995.

Bram Fetter emphasized that this leaves no residues, as everything is used. The pulp serves as feed, for the production of green gas, and the production of ingredients for the soap and paint industry. The lime fertilizer finds its way to agricultural fertilizers. The molasses is a source for other nutritional products. ‘The soil that is delivered with the beets is taken to the land as raw material and it is used to raise dykes.’ Then there is all the water. Sugar beets contain 75% water, which is released during the production process. Bram Fetter joked ‘We're a water factory really. We purify the water and return it to surface water.’

Suiker Unie has its own innovation center, where it researches and develops new production flows from sugar beets. Bram Fetter explained ‘Part of the pulp is converted into green gas with digesters. At the moment, we are generating some 30 million cubic meters of green gas; 20 million is supplied to the gas grid and the rest we use ourselves. That is only a first step.’ Bram Fetter strives for energy-neutral operations. Besides gas, the company also produces bio-ethanol, which is added to petrol in Germany.

The company has pilot plants, where they try to convert the beet fiber in the pulp into a new product. Bram Fetter continued ‘We are striving for a product that can replace fossil raw materials in washing-up liquid. Beet fibers have cleaning properties.’ On a relatively small scale, the company already supplies an ingredient for dishwasher tablets to the market. Bram Fetter has high expectations for biodegradable plastics based on sugar-beet fibers.

For the latter, Bram Fetter is collaborating intensely with the chemical companies in the TopDutch region. ‘The fun part of developing biobased production processes is that we can't do it on our own. We work together with large and small innovative chemical companies.’ Chemport Europe has a keen sustainability ambition, which Bram Fetter believes to offer major opportunities for expanding cooperation. ‘We would like to set up new production processes with companies that have the ambition to produce biobased products.’

Then there is the forgotten part of the sugar beet plant - the leaf. Beet leaf consists of 20% protein, and it is a new frontier in studying new applications for this crop. In October, Suiker Unie opened a pilot plant to isolate the protein in beet leaf. Bram Fetter says ‘We are studying whether beet-leaf protein can substitute meat-based protein in food. You could replace chicken protein in all manner of products and even imitate meat with beet-leaf protein.’ Bram Fetter continued ‘The fact is that sugar beets will be used for more sustainable and healthier aims than just sugar.’

The crop
Sugar beets contain 75% water. In the Low Countries, the sugar content of the beet is relatively high at between 15 and 20%. The rest of the beet consists of fibers, roots and pulp. The sugar content can vary and depends on growing conditions, soil quality and the climate.

The production
In the Netherlands, between 5 and 8 million metric tons of sugar beets are harvested each year. Dutch sugar beets are relatively rich in sugar. The 2019 season is expected to yield approximately 14 metric tons of sugar per hectare. Since 2015, Dutch sugar-beet acreage has been rising significantly and these days the Netherlands is in the top 5 in Europe.

The process
On arrival, the beets are cleaned with powerful water jets and clay and stones are removed. Then the relatively hard tubers are cut into thin chips. They are heated in water to beet juice. The remaining pulp serves as the basis for feed and green gas. Lime is added to beet juice to bind the substances from the beet. This raw juice is boiled and evaporated to thick juice. The sugar is crystallized from the thick juice in large pans. In centrifuges, the white granulated sugar is separated from the brown syrup. The granulated sugar is then dried, cooled, and packaged.

The end products
Thick juice can be processed into sugar or as a raw materials for the biobased (fermentation) industry. The pulp and the beet tails are processed into feed, green gas and are used for biobased ingredients. The filtered lime is reused as betacal, and spread as fertilizer on the beet fields. The molasses is used as food for micro-organisms and yeast. Promising new end products include detergents, coatings, bioplastics and protein for human consumption.