Manipulation of alliinase-generated thiosulfinate flavor profiles in Alliums

摘要: Thiosulfinates (RS (O) SR’) and related compounds in freshly minced tissues of Alliums are responsible for the characteristic fresh flavor of onion, garlic and related species. The emerging understanding that these compounds are intrinsically stable, yet reactive, offers opportunities to manipulate thiosulfinate profiles through simple interventions for the purpose of controlling flavor or bioactivity in Allium preparations. An alkanesulfenic acid (RSOH)“trapping” strategy, based on the reaction of R” SOH with RS (O) SR’to yield new (R” S (O) SR’) species, formed the basis for manipulating organosulfur profiles. Reaction systems, employing crude onion alliinase, pure S-alk (en) yl-L-cysteine sulfoxide (ACSO) substrate and pre-formed thiosulfinate, were used to model this reaction and allow predictions of outcomes to be made which were validated experimentally. The ability to manipulate thiosulfinate profiles using this approach was principally affected by the relative rate of flux of RSOH (conferred by levels of both alliinase and ACSO) and level of pre-formed thiosulfinate introduced into the reaction system. Lower rates of flux of RSOH and greater pre-formed thiosulfinate levels were most conducive to efficient trapping of RSOH and a greater ability to direct the accumulation of specific R” S (O) SR’species (some of which may not normally accumulate in minced Allium tissues). This approach was applied to diluted onion tissue samples supplemented with exogenous thiosulfinate to demonstrate proof of concept. More rigorous testing using only raw and thermally processed tissues of various Allium species, in various combinations, served to demonstrate …