Which compound is responsible for the pungent flavor found in horseradish and mustard seeds?

The compound responsible for the pungent flavor found in horseradish and mustard seeds is sinigrin. Sinigrin is a type of glucosinolate, which is a sulfur-containing compound that, when hydrolyzed, produces various products including allyl isothiocyanate. This specific compound contributes to the sharp, spicy flavor and aroma that horseradish and mustard are known for. The metabolic process of sinigrin leads to the release of these potent flavor compounds, especially when the plant material is damaged, such as through chopping or grinding.

In contrast, digoxin is a cardiac glycoside commonly found in foxglove and does not relate to culinary flavors. Linamarin is another glucosinolate but is primarily found in cassava and does not contribute to the flavor profile of horseradish and mustard. Alliin is associated with garlic and is converted into allicin, which is known for its distinctive taste and smell but does not pertain to horseradish or mustard. Thus, sinigrin stands out as the key compound responsible for the unique flavor characteristics of horseradish and mustard seeds.