| Autor: |
Hixson JL; School of Agriculture, Food and Wine, The University of Adelaide, Waite Campus , PMB 1, Glen Osmond, South Australia 5064, Australia., Hayasaka Y; The Australian Wine Research Institute , P.O. Box 197, Glen Osmond, Glen Osmond, South Australia 5064, Australia., Curtin CD; The Australian Wine Research Institute , P.O. Box 197, Glen Osmond, Glen Osmond, South Australia 5064, Australia., Sefton MA; School of Agriculture, Food and Wine, The University of Adelaide, Waite Campus , PMB 1, Glen Osmond, South Australia 5064, Australia., Taylor DK; School of Agriculture, Food and Wine, The University of Adelaide, Waite Campus , PMB 1, Glen Osmond, South Australia 5064, Australia. |
| Abstrakt: |
Synthesized p-coumaroyl and feruloyl l-tartrate esters were submitted to Brettanomyces bruxellensis strains AWRI 1499, AWRI 1608, and AWRI 1613 to assess their role as precursors to ethylphenols in wine. No evolution of ethylphenols was observed. Additionally, p-coumaroyl and feruloyl glucose were synthesized and submitted to B. bruxellensis AWRI 1499, which yielded both 4-ethylphenol and 4-ethylguaiacol. Unexpected chemical transformations of the hydroxycinnamoyl glucose esters during preparation were investigated to prevent these in subsequent synthetic attempts. Photoisomerization gave an isomeric mixture containing the trans-esters and undesired cis-esters, and acyl migration resulted in a mixture of the desired 1-O-β-ester and two additional migrated forms, the 2-O-α- and 6-O-α-esters. Theoretical studies indicated that the photoisomerization was facilitated by deprotonation of the phenol, and acyl migration is favored during acidic, nonaqueous handling. Preliminary LC-MS/MS studies observed the migrated hydroxycinnamoyl glucose esters in wine and allowed for identification of feruloyl glucose in red wine for the first time. |
