Detection of tropane alkaloid contaminations in unprocessed soybeans and their fate in food and feed processing

Datura stramonium and other nightshade plants commonly occur as weeds and have the potential to contaminate crops with toxic tropane alkaloids. Here, the contamination of soybeans with the tropane alkaloids atropine and scopolamine after co-harvesting with thornapple plants is reported. The potential route of contamination was found to be independent of the thornapple seeds. The further fate of tropane alkaloids in downstream processes was evaluated in laboratory-scale tofu and soybean oil production. It was determined that a relatively small portion of the alkaloids is persistent in the tofu, while the reduction in soybean oil and press cake is less pronounced. No regulation is in place for the maximum amount of tropane alkaloids in soybeans, but the limits for other food crops were exceeded both in the raw and processed goods.