Published 2018-04-10

This post is also available in Swedish

New Mistra Biotech breakthrough: more nutritious potato starch

A research group in Mistra Biotech has recently made a major breakthrough: they have developed a new potato variety with a higher proportion of nutritious ‘slow’ carbohydrates.
‘This is wonderful news. This potato, with its higher content of resistant starch, has many good health characteristics,’ says Xue Zhao, a PhD student researching vegetable food at the Swedish University of Agricultural Sciences (SLU) in Uppsala.

The new potato was developed by a group of plant breeders in Mistra Biotech, headed by Mariette Andersson. This potato’s main characteristic is its relatively high content of ‘resistant starch’ —starch that behaves like fibre; that is, instead of being absorbed by the small intestine, it enters the large intestine undigested. This confers numerous positive health effects. For example, it reduces glucose levels and insulin reactions; optimises bacterial flora in the gut and gives a good boost to processes in the stomach; and can also facilitate weight loss.

The Mistra Biotech plant breeders developed the potato by reducing the activity of two enzymes that bring about the branching of starch molecules in the potato cells.

The aim was to produce a higher amylose content in the potato. Potato starch usually consists of 25% amylose (straight molecules) and 75% amylopectin (branched molecules).

‘The goal was to come up with a potato that had a higher amylose content, and they succeeded,’ says Xue Zhao, a researcher at SLU in Uppsala.

Zhao has contributed to the research by performing the requisite chemical analyses of the potato. She is also the lead author of the paper, where the research results were recently published, in the journal Food Chemistry.

A higher amylose content results in a higher level of resistant starch when the potato is boiled, she explains. But the amylopectin left in the potato also became more like the amylose, and its action ‘slower’ when the potatoes were boiled and the starch recrystallised.

This discovery could have major positive effects in a country like Sweden, where we eat a great deal of potatoes. Today, there are no technical barriers to cultivating the new potato variety on a large scale. The major stumbling block is legislative: getting an EU permit for a genetically modified potato is difficult.

‘This potato was produced with GM (genetic modification. That’s the barrier preventing us from launching it. But my colleagues and I are working on a new solution,’ Zhao says.

What Mariette Andersson and other plant breeders at SLU are trying to do is to develop a similar potato using genome-editing technology, CRISPR-Cas9, known as ‘gene scissors’. Although the results are the same, this technique is less controversial and would not be an obstacle to the cultivation of potatoes.

Text: Thomas Heldmark