Dry roasting a trigger for peanut allergy
1 Oct 2014 by Evoluted New Media
There is a striking difference between the prevalence of peanut allergies in the Western world and the East and it could be down to the way the nuts are prepared.
Dry roasted peanuts are more likely to trigger an allergy than raw peanuts say researchers from the University of Oxford. They believe specific chemical changes caused by the high temperature of the dry roasting process are recognised by the body’s immune system, priming an allergic immune response next time it encounters peanuts.
The team purified proteins from dry roasted and raw peanuts and introduced them to mice in three different ways: injected under the skin; applied to broken skin; and directly into the stomach. Immune responses to further peanut extracts later were also measured.
Mice that had initially been exposed to dry roasted peanuts generated a greatly increased immune response to peanuts, compared to those exposed to raw peanut proteins.
“This is the first time, to our knowledge, that a potential trigger for a peanut allergy has been directly shown,” said Professor Quentin Sattentau, who led the research.
“Our results in mice suggest that dry roasted peanuts may be more likely to lead to peanut allergy than raw peanuts; the dry roasting causes a chemical modification of peanut proteins that appears to activate the immune system against future exposure to peanuts,” said first author Dr Amin Moghaddam.
Dry roasting involves temperatures of 160-170°C; above 130°C the Malliard chemical reaction caused the modification of specific chemical groups in proteins. The researchers believe this reaction in dry roasted peanuts can activate a strong allergic immune response.
The research, published in The Journal of Allergy and Clinical Immunology, is still at an early stage and that it would be premature to avoid roasted peanuts and their products until further work is carried out, said Sattentau.
“We think we have identified the chemical modifications involved in triggering an allergic response to peanuts, and are currently exploring methods that are food industry-friendly to eliminate these groups,” Sattentau said.
