I am one seriously addicted plantsperson. Usually horseradish is a simply blended product, white vineger added and salted to taste. Shallots, garlic or onions are added as flavorer's. Wasabe is totally different. I am going to experiment by drying some horseradish, rehydrating it with oil and some salt and water.
Turmeric seems to be added for coloring.
Chili's are one thing, horseradish is another and so is a real hairy chested homemade mustard. I make all of my own. Including garlic, basil, chili mustards and being the gardener that I am, once even a sweet rose hip mustard. Senf is mustard in German and certainly is a crucifer. Just want to add my two cents.