Screening is now performed to find strawberries with no or little of the allergen protein. Sofar, a colourless, white strawberry variety has been found to be virtually free from the allergen. The allergen was identified using blood sera from patients experiencing adverse reactions to strawberry. The protein then discovered turned out to be a not completely unknown one.
"This protein resembles a previously known allergen in birch pollen," says Cecilia Emanuelsson at the Dept of Biochemistry. A primary allergy against birch pollen can in turn evoke secondary allergic reactions against berries, fruit and some vegetables. That does not necessarily mean that all birch pollen allergic individuals react against strawberries. But some do, and some face the risk of developing such secondary adverse reactions. Birch-pollen related food allergy is a well-known phenomenon and especially common in Northern Europe, but the actual number of persons affected today is difficult to estimate.”
There are some observations among breeders that allergic individuals can eat a white strawberry variety without problems. When the research group in Lund investigated such a white strawberry they found that it contained very little of the strawberry allergen. In Sweden breeders have worked for some time with breeding to improve the quality of white strawberries to become as tasty as the red ones. Some plant shops occasionally provide plants of white strawberry.
"The allergen is in some way related to the red colour but it is not clear exactly how, we need to investigate more proteins," says Rikard Alm. "We are now investigating the biological variation of the strawberry allergen, between different strawberry varieties, and within one and the same variety depending on cultivation conditions.”
MEDICA.de; Source: Vetenskapsrådet (The Swedish Research Council)