Peanut processing techniques increase allergen risk

On average, Americans consume more than three kilos of peanuts and peanut products each year. Although the nutty legumes are a good source of vitamins and fibre, for a small but growing sector of the population, peanuts can also induce an allergic reaction. Scientists investigating the reasons for this increase have found that roasting peanuts can cause a marked increase in their allergenic properties.

On average, Americans consume more than three kilos of peanuts and peanut products each year. Although the nutty legumes are a good source of vitamins and fibre, for a small but growing sector of the population, peanuts can also induce an allergic reaction. Scientists investigating the reasons for this increase have found that roasting peanuts can cause a marked increase in their allergenic properties.

Agricultural Research Service (ARS) scientists in New Orleans are currently looking for solutions to the peanut allergy problem. In one research project, they are trying to determine how certain processing methods affect peanut allergenicity, and in a second project they are looking to see if certain peanut cultivars are less allergenic than others.

Soheila J. Maleki and Si-Yin Chung at the ARS Southern Regional Research Center (SRRC) in New Orleans found that roasting peanuts causes a marked increase in their allergenic properties. Although a few other scientists have noted thiscorrelation, no one has ever suggested a reason why - until now.

Maleki recently published two papers addressing specific structural and molecular/biochemical changes that raw peanut proteins undergo during roasting that may contribute to increases in their allergenic properties.

According to Maleki, if there are processing methods that can increase the allergenic properties of peanuts, there may also be processing methods that can reduce them.Even if there are not, SRRC scientists believe they may still be able to create a safer nut. Maleki and collaborators are currently developing antibodies against three of the best- characterised peanut allergens (Ara h 1, Ara h 2 and Ara h 3). They hope to use these antibodies to screen the US core peanut germplasm collection and determine the levels of these allergens in each cultivar.

Cultivars with naturally lower levels of allergens could thenbe crossbred to develop a hypoallergenic peanut plant.So far, the researchers have screened part of the germplasm collection forAra h 1 and have found major differences in the levels of this allergen invarious cultivars. The ARS reports that scientists are currently repeating these experiments to confirm their findings.