Purified Cashew Proteins Lend Insight into Allergic Reactions

05 Feb 2016 --- It's well known that peanuts can cause severe reactions in people who are allergic, but research suggests that the risk of developing a life-threatening reaction could be higher for those allergic to cashews. Now scientists have come up with a fast and simple method to purify the three main cashew allergens to help better grasp how they work and their effects on people. Their report appears in ACS' Journal of Agricultural and Food Chemistry.

Allergies to tree nuts and peanuts can cause mild symptoms, such as hives and itchy eyes. But some people who are allergic experience anaphylaxis, a life-threatening reaction that includes shortness of breath, swelling, dizziness and other symptoms. Scientists have identified three proteins associated with cashew allergies, but no one had isolated them with a high degree of purity or characterized them. Doing so, however, would help identify which specific allergen people react to, how the proteins might cross react with other allergens and potentially how to treat the allergy. Harry J. Wichers and colleagues decided tackle this challenge.

Professor Wichers told FoodIngredientsFirst: "One of the reasons for us to develop the project was the suspicion that allergy to cashew became more prevalent amongst children. However, also adults suffer from it; it looks like an allergy that is mostly not out-grown, as fortunately often as the case for e.g. cow’s milk allergy. Already very young children, that are unlikely to ever have consumed a cashew nut, can be allergic to it. The question how and where the sensitisation develops, is still un-answered."

The researchers used three different methods: precipitation, ultrafiltration and gel filtration chromatography -- to purify the three main cashew allergens. They then identified the proteins' subunits. Additionally, testing found a difference in how allergens bound to immunoglobulin E, an allergen-binding antibody, in Dutch children and American adults, shoring up previous suggestions that geography and age can play a role in allergies. Researchers say further studies can build on these results to analyze allergen structure, cashew varieties and the stability of proteins during processing.

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