Heat-induced formation of mepiquat by decarboxylation of pipecolic acid and its betaine derivative. Part 2: Natural formation in cooked vegetables and selected food products

- Mepiquat occurs at μg/kg levels in a variety of cooked vegetables.
- It can be considered as a naturally formed agro-industrial chemical in cooked foods.
- The amount of mepiquat found in cooked foods is unlikely to be a health concern.

Mepiquat (N,N-dimethylpiperidinium) is a plant growth regulator registered for use as its chloride salt in many countries on cereals and other crops. Recent model system studies have shown that natural chemicals present in crop plants, such as pipecolic acid and pipecolic acid betaine, may furnish mepiquat through different chemical pathways, when subjected to temperatures in the range of 200 °C. In this study, we cooked raw vegetables that did not contain mepiquat to a palatable state using different traditional cooking methods, and detected mepiquat in 9 out of 11 oven-cooked vegetables, reaching up to 189 μg/kg dry wt in oven-cooked broccoli. Commercial oven potato fries generated mepiquat during cooking, typically in the range of 20-60 μg/kg. Only traces of mepiquat (<5 μg/kg) were found in commercial potato crisps. This work demonstrates that mepiquat occurs at μg/kg levels in a variety of cooked vegetables, including potatoes.