1, horseradish and mustard is not the same thing.
2, the definition of different: the market cheaper "green mustard", mostly made of horseradish. It is cruciferous horse radish genus. However, horseradish root is light yellowish-white, adding a green coloring to become the appearance of the market. The English name for horseradish is Horseradish, which translates to "horse radish". Traditionally, mustard is a condiment made from ground mustard seeds, and it is one of the world's most popular and oldest spices.
3, the flavor is different: horseradish contains pungent isothiocyanate compounds that have antiseptic properties. The intact mustard seed itself is not spicy. After the mustard seed is crushed and water is added, which contains mustard thioglycosides and mustard enzyme before the hydrolysis reaction, generating pungent isothiocyanates.
4, origin and time of appearance and the initial role of different: horseradish is native to Central Europe, the early just medicinal plants, used to treat coughs, rheumatism and other diseases. Mustard seeds have appeared in the Stone Age, ancient Europeans generally regarded mustard seeds as medicine rather than food, used to treat toothache and a series of diseases.