Sinalbin and sinigrin release isothiocyanates upon enzymatic hydrolysis.

• A. True
• B. False
• C. Not stated
• D. Cannot be determined

Answer: (A)

Glucosinolates such as sinalbin and sinigrin are cleaved by the plant enzyme myrosinase when the tissue is damaged. This enzymatic hydrolysis breaks the glucosinolate into glucose, sulfate, and an unstable aglycone that rearranges to an isothiocyanate. Specifically, sinalbin yields a p-hydroxybenzyl isothiocyanate and sinigrin yields allyl isothiocyanate. So the statement is true. Context: the isothiocyanates are responsible for the characteristic pungent flavors of cruciferous vegetables, and their formation can be influenced by conditions like pH and certain proteins that can direct the reaction toward nitriles instead of isothiocyanates, but the primary outcome of enzymatic hydrolysis is the production of isothiocyanates.