Producing 'low acrylamide risk' potatoes

Acrylamide is a chemical that is considered to be probably carcinogenic (cancer causing) and which affects the nervous and reproductive systems. The discovery in 2002 that it is present in many cooked foods was, therefore, quite a shock for the science community, the food industry and regulatory authorities. The disquiet was compounded when it became clear that acrylamide is formed not as a result of the presence of an additive or a change in agricultural or food processing methods that could be readily reversed, but from naturally-occurring substances reacting at the high temperatures achieved during the basic cooking processes of frying, baking and roasting. Any complacency that had built up since that first discovery has just been swept aside by the publication of two studies linking the eating of 'high-acrylamide' foods with cancer in humans. Foods derived from potatoes have a particularly high acrylamide risk. The major route for acrylamide formation is the breakdown of an amino acid called asparagine in the presence of sugars. This is part of the Maillard reaction, which occurs during the cooking of food and is also responsible for the production of flavour and colour. This puts a constraint on what food processors can do to deal with the problem and, despite the fact that some progress has been made, the levels of acrylamide in foods such as French-fried potatoes, crisps and other potato-based snacks are still commonly several hundred parts per billion (ppb). While no limit has yet been set for food, regulatory authorities around the world have stated that they wish to see dietary intake of acrylamide reduced. Methods for lowering acrylamide in foods include reducing cooking times and temperatures and making the processing conditions more acidic. However, these methods are reaching the limit of what can be achieved. The use of asparaginase reduces acrylamide levels in certain processed foods but it is ineffective in, for example, sliced and chipped potatoes and is unsuitable for use in the home. An alternative is to produce raw materials with reduced levels of sugars and asparagine. This is the aim of this project, focusing on potato. The strategic target is to produce potatoes that retain sufficient sugars and amino acids for the generation of colour and flavour compounds but which produce less acrylamide. The project will involve researchers from Rothamsted Research, the University of Reading and Scottish Crops Research Institute, and key companies in potato production, processing and marketing. Outputs will include advanced knowledge of the mechanisms regulating asparagine and sugar accumulation in potatoes, the identification of important genes that are responsible for the differences between varieties and 'proof of concept' using genetic modification. The project will generate new tools for plant breeders to use in breeding programmes and will enable a better understanding of the effects of plant nutrition on acrylamide risk.

Acrylamide, a neurotoxin and possible carcinogen, was first reported in cooked foods in 2002, causing considerable disquiet within the food industry and regulatory authorities. Concern has been heightened recently by the publication of two studies linking high dietary intake of acrylamide with cancer in humans. Foods with the highest levels of acrylamide are carbohydrate-rich and cooked at high temperatures and the thermal degradation of free asparagine in the presence of sugars during the Maillard reaction is the major route for acrylamide formation. This reaction also generates desirable flavours and colours. Methods for lowering acrylamide in foods include reducing cooking times and temperatures and lowering the pH. However, these methods are reaching the limit of what can be achieved. The use of asparaginase reduces acrylamide levels in certain processed foods but it is ineffective in sliced and chipped potatoes and unsuitable for use in the home. An alternative is to produce raw materials with reduced levels of sugars and asparagine. This is the aim of this project, focusing on potato, a major UK crop with a high acrylamide risk. The strategic target is to produce potatoes that retain sufficient sugars and amino acids for the generation of colour and flavour compounds but which produce less acrylamide. The project will involve researchers from Rothamsted Research, the University of Reading and Scottish Crops Research Institute, and key companies in potato production, processing and marketing. Outputs will be advanced knowledge of mechanisms regulating asparagine and sugar accumulation in potatoes, the identification of genes underpinning trait variation and proof of concept using transgenic approaches. The project will generate gene-specific markers and improved germplasm for breeding programmes. It will also enable a better understanding of the effects of plant nutrition on acrylamide risk.