Mar 4, 2010

Basic info

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The potato as a renewable raw material.

Potato starch

A genetically modified potato with the proprietary name "Amflora", which predominantly produces amylopectin starches, has been approved for cultivation in the EU at the beginning of March 2010.

Alongside wheat and maize, the potato is an important supplier of starch – particularly in Germany. It provides high yields per hectare, has a higher swelling power and viscosity than its competitors and has the largest starch grains.

Since the 1980s, starch extraction from potatoes has trebled. And starch has long ceased to be used only in the food industry – this renewable raw material is also a component of paper, construction materials, adhesives and many more non-food products.

Because of its ability to bind and thicken, starch is an extremely versatile raw material, which has long been of interest to sectors even outside the food industry.

In recent years there have been many product developments based on starch, including biodegradable eco-plastic. Foam starch-based packaging chips are now widespread. And the use of bioplastics is already established in the production of carrier bags that can also be used for collecting compostable waste, and in the production of trays for foodstuffs.

Starch and its constituents

Industrial processing poses entirely new challenges for the industrial crop. A potato intended for starch extraction must above all have a high starch content. The starch composition should be ideally suited to the process and it must be of a standard quality and consistency for the industrial process.

In biochemical terms, starch is a polysaccharide consisting of individual sugar components (glucoses). Not all starches are alike; the ratio of amylose and amylopectin, the two starch constituents present in the plant, determines the characteristics. Normally the ratio of amylose to amylopectin is around 1:4 to 1:5. The most highly valued starch characteristics such as good adhesive properties are due to the amylopectin, which is therefore the more coveted component.

Separating the two starch components is very costly for the processing industry and results in a large quantity of wastewater. For this reason plants with a high amylose or amylopectin content are sourced as a raw material, depending on the application.

Customised raw materials for industrial production

Breeders are trying hard to meet all these requirements, but options are limited in potato breeding. The cultivated potato is a tetraploid, i.e. it has four sets of chromosomes and therefore a very complex inheritance pattern. It is extremely difficult to cross one, let alone several, desirable traits - especially since several genes are often responsible for a single characteristic.

Genetic engineering makes it possible to inhibit an enzyme within the potato that is responsible for the formation of amylose. It is now possible to modify the starch composition in the potato in a targeted manner. A genetically modified potato with the brand name Amflora, which primarily produces amylopectin starch, wurde Anfang März 2010 in der EU für den Anbau zugelassen.

Recently, an amylose-free potato has been successfully developed without the use of gene technology. The method is called ‘Tilling’ (targeting induced local lesions in genomes). In this process a directed point mutation is chemically created in the genome. Using molecular biological methods plants that show the desired genetic changes can be rapidly detected.