Cruciferous vegetables are known for their high concentration of glucosinolates; isothiocyanates are formed from these molecules . In order to form isothiocyanates, the enzyme myrosinase must be present. This enzyme is present these cruciferous plants, but it is stored different areas of the cell from the glucosinolates to prevent internal harm to the plant.

When these glucosinolate containing plants incur physical injury, the enzyme myrosinase and the glucosinolates come in contact. Then the glucosinolates are broken down into different molecules; the products include isothiocyanates. This is actually part of the plant’s natural defense system because this reaction causes the plant to have a bitter taste, and is thus less palatable. Different cruciferous plants have different glucosinolates, which result in different isothiocyanate products.(Chop, crush, and chew your broccoli well to release the max amount of myrosinase!)

Now we turn up the heat!

Glucosinolates are actually very stable molecules and are even stable at high temperatures. However, the enzyme myrosinase is heat sensitive. When glucosinolate containing plants are cooked, the myrosinase is deactivated and cannot react to form isothiocyanates and other products. So, the amount of isothiocyanates present are greatly affected by heat. More heat, less isothiocyanates.

There is one, sort-of, exception. The bacteria in the human gut does have a minimal about of myrosinase activity, and can thus convert some of the glucosinolates into isothiocyanate. However, the amount of isothiocyanates produced in this conversion are considerably less than the amount obtained from the uncooked plant.

I now want to know what other plants have these type of beneficial enzyme relationships that result in favorable products for human health. I plan on continuing in this area of research to see what I can discover. In almost all raw foodist books, I hear enzymes enzymes enzymes. I was never sure if those claims had any merit, but I now know they do – well, at least in *this* case for a particular molecule in cruciferous vegetables.