Eaten only occasionally, sesame seeds will not contribute much to an overall acrylamide load. Photo / Getty Images
Question: Do the potential dangers to health resulting from eating roasted nuts also occur with roasted seeds? I am particularly concerned about roasted sesame seeds.
Answer: Nuts and seeds are small but mighty; packed with nutrients, fibre, protein and healthy fats that benefit our heart health and more. However, roasting and toasting processes can create an undesirable chemical contaminant called acrylamide in certain foods, including nuts and seeds.
Acrylamide is categorised as a potential human carcinogen by the World Health Organisation. It is formed during the cooking process in foods containing sugars and an amino acid called asparagine that produces desirable new flavours and aromas, as well as the chemical contaminant. Although acrylamide has not been linked directly to cancer in humans, in animal studies it has caused cancer, so it is recommended we take steps to reduce our acrylamide intake.
The concentration of acrylamide in carbohydrate-rich foods can be influenced at several points along the production chain, from selective plant breeding and fertilisation practices to altering recipes to include ingredients that inhibit acrylamide production.
A recent study involving researchers from AUT University found that extracts from green tea could reduce acrylamide formation during bread baking.
Processing ingredients can also alter acrylamide formation – washing and blanching foods can reduce acrylamide levels – and the cooking process, including temperature and duration, also alters concentrations.
A 2012 study found the greatest contributors of acrylamide to the typical New Zealand diet were potato products, bread, breakfast cereals and drinks.
New Zealand potato crisps and corn chips had a mean acrylamide level of 580-596 micrograms per kilogramme of chips. The mean acrylamide levels in toasted breads was 58-72mcg per kg of bread.
As well as potato products, breads, cereals, cakes and biscuits, acrylamide tends to accumulate in lower moisture foods, including roasted nuts and seeds.
Levels on average vary from 33-251mcg per kg of roasted nuts and seeds, depending on the variety. However, a 2019 study found high amounts of acrylamide (135-633mcg per kg) in roasted sesame seeds.