Volatile thiols precursors from cysteine

B.5 Precursors of Volatile Thiols Derived from Cysteine. 286... 

Recent studies have focused on cysteine-S-conjugates as varietal aroma precursors (see Baumes, 2009). Chemically, these odorless compounds are S-substituted derivatives of L-cysteine, differing in the attached to sulfur atom. During fermentation, extremely odorous volatile thiols are formed from these precursors (see Dubourdieu and Tominaga, 2009). One of these thiols, 3-sulfanylhexan-l-ol (3SH), is known as an important aroma... 

From an organoleptic standpoint, S-cysteine conjugates are responsible for the nnnsnal sensation known as Sanvignon Blanc aftertaste, perceived on tasting Sanvignon Blanc grapes or mnst. Enzymes in the month probably have a /S-lyase activity capable of releasing volatile thiols from their cysteinylated precursors in jnst a few seconds. 

Volatile thiols are present in fruits and vegetables combined forms, as S-cysteine and S-glutathione conjugates, and are released from these precursors by the action of L-cysteine-S-conjugate thiol-lyase (deaminating) during fermentation (Figure 8.58). For example, the precursors of... 

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