Are Dried Kidney Bean Patties Toxic?

I heard that kidney beans should not be eaten raw because of toxic ingredients. I make patties out of dried kidney beans that I fry in a pan. Is the heat sufficient – as with cooking – to render the toxins harmless?

All beans contain the plant toxin phasin, which belongs to the group of lectins. In the plant, the poison serves to ward off predators. Kidney beans in particular have a higher content. The phasin impedes the transport of oxygen in the blood because it sticks together the red blood cells, which are responsible for transporting oxygen. The epithelial cells in the intestine can also be damaged and the absorption of nutrients through the intestine disrupted.

Depending on the amount ingested, the consumption of raw beans can lead to stomach upset, intestinal inflammation with diarrhea and even death. Children are particularly at risk because of their low body weight and small amounts are enough to trigger symptoms. The first symptoms appear after 2 to 3 hours.

To destroy the phasin, raw beans must be cooked for at least 15 minutes. When preparing the patties in the pan, there is a possibility that not enough heat gets to the core of the patties in sufficient time and that there are residual amounts of phasin in them.

A dough for bean patties, especially in mass catering, should therefore always be made from cooked beans.