30 June 2005: The colour of strawberry allergy

The mystery of why some people are allergic to strawberries is about to be revealed. Unpublished data detail how one protein out of thousands encoded in the strawberry’s genetic make-up triggers an allergic reaction that leads to itching and swelling in the mouth and throat.

Biochemists at Lund University, Sweden, identified the protein with electrophoresis and mass spectrometry after analysing large data sets using bioinformatics. 

The scientists found that the allergenic protein resembles a known allergen found in birch pollen. Birch-pollen-related food allergy is well known:   food allergies can be secondary allergies for those with birch pollen allergy.  

Anecdotal evidence from strawberry breeders suggests that people with strawberry allergies can eat a white strawberry variety without adverse reactions. The Lund researchers investigated a white strawberry variety called Sofar, and found that it is almost free of the allergen. Swedish breeders are working on making the white strawberry as flavoursome as the red ones. 

’The allergen is in some way or other related to the red colour but it is not clear exactly how,’ said Rikard Alm, who worked on the project. ’We need to investigate more proteins. 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.’

Cecilia Emanuelsson from the biochemistry department at Lund University explained how this will be done: ’The gel with the separated proteins is like a map and it actually opens up new possibilities for plant breeding. By comparing strawberries with different properties and their maps.we may be able to discover which role different proteins play in, for example, frost resistance, colour, taste, etc and find biomarkers for different traits.’ Fiona Salvage