A new type of wheat, chock full of healthy fibre, has been launched by an international team of plant geneticists. The first crop of this super wheat was recently harvested on farms in Idaho, Oregon and Washington state in the US, ready for testing by various food companies. Food products are expected to hit the US market in 2019. They will be marketed for their high content of ‘resistant starch,’ known to improve digestive health, be protective against the genetic damage that precedes bowel cancer and help protect against Type 2 diabetes.
‘The wheat plant and the grain look like any other wheat. The main difference is the grain composition: the Arista wheat contains more than ten times the level of resistant starch and three to four times the level of total dietary fibre, so it is much better for your health, compared with regular wheat,’ says Ahmed Regina, plant scientist at Australian science agency CSIRO.
Starch is made up of two types of polymers of glucose – amylopectin and amylose. Amylopectin, the main starch type in cereals, is easily digested because it has a highly branched chemical structure, whereas amylose has a mainly linear structure and is more resistant.
Breeders drastically reduced easily digested amylopectin starch by downregulating the activity of two enzymes, so increasing the amount of amylose in the grain from ca20 to 30% to an impressive 85% (Plant Biotech. J. lnt., 2015, 13, 1276).
The non-GM breeding approach works because the building blocks for both amylopectin and amylose starch synthesis are the same. With the enzymes involved in making amylopectin not working, more blocks are then available for amylose synthesis.
‘Resistant starch is starch that is not digested and reaches the large intestines where it can be fermented by bacteria. Usually amylose is what is resistant to digestion,’ comments Mike Keenan, food and nutrition scientist at Louisiana State University, US. ‘Most people consume far too little fibre, so consuming products higher in resistant starch would be beneficial.’
He notes that fermentation of starch in the gut causes the production of short-chain fatty acids such as butyrate that ‘have effects throughout the body, even the mental health of humans’.
The super-fibre wheat stems from a collaboration begun in 2006 between French firm Limagrain Céréales Ingrédients, Australian science agency CSIRO, and the Grains Research and Development Corporation, an Australian government agency.
This resulted in a spin out company, Arista Cereal Technologies. After the US, Arista reports that the next markets will be in Australia and Japan.