A Little Rosemary Can Go A Long Way In Reducing Acrylamide In Food

"Acrylamide is formed during the preparation of many ordinary foods. It is therefore important both for consumers and the food industry to find methods to reduce the acrylamide content," says Kit Granby, senior scientist at the National Food Institute, Technical University of Denmark.

Over the past five years, a research project has identified several ways of reducing acrylamide in foods. The project is a collaboration between the National Food Institute and the Department of Systems Biology at the Technical University of Denmark, the Faculty of Life Sciences at the University of Copenhagen and five Danish food companies.

Tests with processing conditions

Acrylamide is a chemical formed when frying, baking or grilling carbohydrate-rich foods at temperatures above 120°C. Acrylamide is thus found in a number of foods, such as bread, crisps, French fries and biscuits.

In addition to the heating temperature, tests carried out during the project also show that factors such as time of processing, pH, water content, water activity and the content of the amino acid asparagine and sugar in the raw ingredients influence the formation of acrylamide. For example, the longer the cooking time and the lower the water content, the higher the acrylamide content in the heat-processed food.

"By changing and optimising these factors when producing foods, the acrylamide content of many different types of products can be reduced considerably," says Kit Granby.

Tests with antioxidants

The collaborative project also included a PhD research project which tested the addition of different antioxidants.

The addition of rosemary to dough prior to baking a portion of wheat buns at 225°C reduced the acrylamide content by up to 60 per cent. Even rosemary in small quantities – in one per cent of the dough – was enough to reduce the acrylamide content significantly.

Flavonoids are another type of antioxidant found, among other things, in vegetables, chocolate and tea. Tests also showed that the addition of the flavonoids epicatechin and epigallocatechin from green tea considerably reduced the acrylamide content.

"Antioxidants are substances which inhibit the formation of free radicals in the food and eliminate free radicals in the body. Our tests indicate that free radicals are formed when cooking and potentially increasing the acrylamide content in certain foods," explains Rikke Vingborg Hedegaard, PhD at the National Food Institute, Technical University of Denmark, who is responsible for the PhD project.

"However, the findings do not show a general association between antioxidants and reducing acrylamide in foods. The tests indicate that different antioxidants do not have the same effect on the formation of acrylamide, and that it is important how antioxidants are added to a product to have an effect on the acrylamide content," adds Rikke Vingborg Hedegaard.

The above findings are just some of the results obtained by the research collaboration project. Other tests show that blanching, salt and the enzyme asparaginase may reduce the acrylamide content in potato products.

The findings have been published in a number of scientific journals, most recently in the journals European Food Research and Technology, Food Chemistry, the Journal of Agricultural and Food Chemistry and the Journal of Food Engineering.