The Invisible Tropical Tuber Crop: Edible Aroids (Araceae) Sold as "Tajer" in the Netherlands

Edible aroids (plants from the family Araceae) are among the top five most cultivated tuber crops globally, but their consumer acceptance is hindered by acridity. Aroids contain sap that severely irritates the throat and lips if not properly processed. However, no in-depth studies exist on acridity in edible aroids and how to diminish it. We used ethnobotanical methods to document the diversity of edible aroids available in the Dutch marketplace and how consumers handle acridity. We grew corms in a greenhouse to obtain additional morphological information and used flow cytometry to assess ploidy. We collected 73 samples and interviewed 71 people. At least three species, Colocasia esculenta, Xanthosoma violaceum, and Caladium bicolor, were sold under the generic name "tajer." Different plant parts with various forms of processing were imported from diverse geographic origins and sold mainly to immigrant customers. Interviewees mentioned various processing methods to avoid and reduce acridity. We distinguished nine cultivar groups of Colocasia esculenta and four of Xanthosoma violaceum. Both Colocasia esculenta and Xanthosoma violaceum were also cultivated in Dutch greenhouses. We present the first report on edible aroids cultivation in northern Europe and draw attention to the lack of labeling and cooking instructions.