Aug 14, 2006

Archive

Send

Fructan potatoes

Tubers with dietary fibre

A new type of potato has been developed at the Max Planck Institute for of Molecular Plant Physiology in Golm: Thanks to two newly introduced genes, in addition to starch this potato also produces special carbohydrates known as fructans. These dietary fibres, which are found in abundance in artichokes and chicory, are thought to have a beneficial effect on health. Although there are no further plans to bring the fructan potato from Golm onto the market, it nonetheless represented an interesting model organism for biological safety research. Between 2001 and 2004, one research association looked at whether the novel sugar components not previously found in potatoes could lead to modified interactions with the environment.

Fructans, e. g. inulin, are dietary fibres with a prebiotic effect: they improve the gut flora by promoting the “friendly” bacteria at the expense of the “harmful” ones. This does not simply aid digestion and increase absorption of certain minerals – some studies have even found evidence of improved blood lipid levels (less cholesterol) and a reduced risk of colon cancer.

Inulin from chicory. Chicory is currently the main source of inulin, but it could also be produced by genetically modified potatoes.

Meanwhile various food products enriched with fructans have appeared on the market. Most of these yoghurts and dairy desserts combine fructan additives (prebiotics) with special ‘healthy’ lactic acid bacteria such as LC1 or Bifido (probiotic) strains to enhance their beneficial effect.

Inulin is another fructan. It is found mainly in chicory, artichokes, Jerusalem artichokes, garlic and onions. Some nutritionists believe that natural inulin absorption through food is too low to be of any health benefit. Inulin is already extracted from chicory and processed to provide a functional food additive.

Fructan potato with artichoke genes

Inulin enrichment is also of interest in the field of genetic engineering. Various groups and companies are working on sugar beet or potatoes with higher inulin contents.

Researchers at the Max Planck Institute of Molecular Plant Physiology in Golm have succeeded in stimulating potatoes to produce inulin/fructan. Initially researchers were interested in developing their understanding of the metabolic pathway by which the sugar building blocks link up to produce inulin in artichokes. Two enzymes were discovered which control the critical transformation process. Having successfully located the genes for both enzymes in the genome of the artichoke and transferred them to that of the potato, the tubers actually produced inulin - in the long-chain and particularly digestion-resistant variant typical of artichokes.