| Texto completo | |
| Autor(es): |
de Almeida, Natalia E. C.
[1]
;
Homem-de-Mello, Paula
[2]
;
De Keukeleire, Denis
[3]
;
Cardoso, Daniel R.
[1]
Número total de Autores: 4
|
| Afiliação do(s) autor(es): | [1] Univ Sao Paulo, Inst Quim Sao Carlos IQSC, BR-13560970 Sao Carlos, SP - Brazil
[2] Univ Fed ABC, BR-09210170 Sao Paulo - Brazil
[3] Univ Ghent, Fac Pharmaceut Sci, B-9000 Ghent - Belgium
Número total de Afiliações: 3
|
| Tipo de documento: | Artigo Científico |
| Fonte: | Journal of Agricultural and Food Chemistry; v. 59, n. 8, p. 4183-4191, APR 27 2011. |
| Citações Web of Science: | 11 |
| Resumo | |
The iso-alpha-acids or isohumulones are the major contributors to the bitter taste of beer, and it is well-recognized that they are degraded during beer aging. In particular, the trans-isohumulones seem to be less stable than the cis-isohumulones. The major radical identified in beer is the 1-hydroxyethyl radical; however, the reactivity between this radical and the isohumulones has not been reported until now. Therefore, we studied the reactivity of isohumulones toward the 1-hydroxyethyl radical through a competitive kinetic approach. It was observed that both cis- and trans-isohumulones and dihydroisohumulones are decomposed in the presence of 1-hydroxyethyl radicals, while the reactivities are comparable. On the other hand, the tetrahydroisohumulones did not react with 1-hydroxyethyl radicals. The apparent second-order rate constants for the reactions between the 1-hydroxyethyl radical and these compounds were determined by electron paramagnetic resonance (EPR) spectroscopy and electrospray ionization-tandem mass spectrometry {[}ESI(+)-MS/MS]. It follows that degradation of beer bitter acids is highly influenced by the presence of 1-hydroxyethyl radicals. The reaction products were detected by liquid chromatography electrospray ionization-ion trap-tandem mass spectrometry (LC-ESI-IT-MS/MS), and the formation of oxidized derivatives of the isohumulones was confirmed. These data help to understand the mechanism of beer degradation upon aging. (AU) | |
| Processo FAPESP: | 08/08773-0 - Reatividade de iso-alfa-ácidos e seus derivados hidrogenados frente ao radical 1-hidroxietil: implicações na perda de qualidade sensorial da cerveja |
| Beneficiário: | Natália Ellen Castilho de Almeida |
| Modalidade de apoio: | Bolsas no Brasil - Mestrado |
| Processo FAPESP: | 09/00858-0 - Mecanismo e conseqüências de processos redox em alimentos: aspectos químicos e fotoquímicos da deterioração oxidativa e atividade antioxidante de cerveja e produtos lácteos |
| Beneficiário: | Daniel Rodrigues Cardoso |
| Modalidade de apoio: | Auxílio à Pesquisa - Regular |