Browsing by Author "Freitas, Ana I."
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- Is sotolon relevant to the aroma of Madeira Wine blends?Publication . Gaspar, João M.; Freitas, Ana I.; Zhao, Qianzhu; Leça, João M.; Pereira, Vanda; Marques, José C.Madeira wine (MW) oxidative aging results in the formation of several key aromas. Little is still known about their odor relevance to the aroma of the most commercialized MWs. This report presents an in-depth study of the odor impact of sotolon in MW blends. First, its odor perception was estimated in MWs according to ASTM E679, testing different 3-year-old (3-yo) commercial blends. The odor relevance of sotolon in the aroma of 3-, 5-, and 10-yo commercial blends (89 MWs) was then appraised by calculating its Odor Activity Value (OAV), after determining its content by RP-HPLC-MS/MS. The sotolon odor perception in MW was as low as 23 µg/L, although it was found that little differences in the wine matrix influenced its perception. OAVs varied between 0.1 and 22, increasing with the blend age. Considering that 16% of the OAVs are higher than 10 (mostly ≥ 10-yo), sotolon was found to be a key contributor to the overall aroma MW blends.
- Methylenetetrahydrofolate reductase gene, homocysteine and coronary artery disease: the A1298C polymorphism does matter. Inferences from a case study (Madeira, Portugal)Publication . Freitas, Ana I.; Mendonça, Isabel; Guerra, Graça; Brión, Maria; Reis, Roberto P.; Carracedo, Angel; Brehm, AntónioElevated levels of plasma homocysteine, an independent risk factor and a strong predictor of mortality in patients with coronary artery disease (CAD), can result from nutritional deficiencies or genetic errors, including methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C polymorphisms. The contribution of these polymorphisms in the development of CAD remains controversial. We analysed the impact of MTHFR C677T and A1298C on fasting homocysteine and CAD in 298 CAD patients proved by angiography and 510 control subjects from the Island of Madeira (Portugal). After adjustment for other risk factors, plasma homocysteine remained independently correlated with CAD. Serum homocysteine was significantly higher in individuals with 677TT and 1298AA genotypes. There was no difference in the distribution of MTHFR677 genotypes between cases and controls but a significant increase in 1298AA prevalence was found in CAD patients. In spite of the clear effect of C677T mutation on elevated homocysteine levels we only found an association between 1298AA genotype and CAD in this population. The simultaneous presence of 677CT and 1298AA genotypes provides a significant risk of developing the disease, while the 1298AC genotype, combined with 677CC, shows a significant trend towards a decrease in CAD occurrence. The data shows an independent association between elevated levels of homocysteine and CAD. Both MTHFR polymorphisms are associated with increased fasting homocysteine (677TT and 1298AA genotypes), but only the 1298AA variant shows an increased prevalence in CAD group. Odds ratio seem to indicate that individuals with the MTHFR 1298AA genotype and the 677CT/1298AA compound genotype had a 1.6-fold increased risk for developing CAD suggesting a possible association of MTHFR polymorphisms with the risk of CAD in Madeira population.
- Polimorfismos do gene da Paraoxonase humana e risco de doença coronáriaPublication . Mendonça, M. Isabel; Reis, R. Palma dos; Freitas, Ana I.; Sousa, Ana C.; Pereira, Andreia; Faria, Paula; Gomes, Susana; Silva, Bruno; Santos, Nuno; Serrão, Marco; Ornelas, Ilídio; Freitas, Sónia; Araújo, José J.; Brehm, António; Cardoso, A. AlmadaIntrodução: As doenças complexas como a doença das artérias coronárias (DAC), a hipertensão e a diabetes, são usualmente causadas pela susceptibilidade individual a múltiplos genes, factores ambientais e pela interacção entre eles. As enzimas da paraoxonase humana (PON), particularmente a PON1, têm sido implicadas na patogenia da aterosclerose e da DAC. Dois polimorfismos comuns na região codificante do gene, com substituição Glutamina (Q) /Arginina (R) na posição 192 e Leucina /Metionina na posição 55 influenciam a actividade da PON1. Vários estudos têm investigado a associação entre os polimorfismos da PON1 e a DAC, com resultados contraditórios. Objectivo: 1- Avaliar a associação dos polimorfismos da PON1 com o risco de DAC. 2-Estudar a interacção destes polimorfismos com outros situados em genes candidatos diferentes, na susceptibilidade para o aparecimento da DAC. Material e Métodos: Estudámos em 298 doentes coronários e 298 controlos saudáveis, através de um estudo caso/controlo, o risco de DAC associado aos polimorfismos da PON1, 192Q/R e 55L/M. Numa segunda fase avaliámos o risco das interacções polimórficas PON1 192 RR + MTHFR 1298 AA; PON1 192 R/R + ECA DD; PON1 192 R/R + ECA 8 GG. Finalmente construímos um modelo de regressão logística (no qual entraram todas as variáveis genéticas, ambientais e bioquímicas, que tinham mostrado significância estatística na análise univariada), para determinar quais as que se relacionavam de forma significativa e independente com DAC. Resultados: Verificámos que o genótipo PON155 MM tinha uma distribuição superior na população doente mas não atingia significância estatística como factor de risco para DAC. O PON1 199 RR apresentou um risco relativo 80% superior relativamente à população que o não possuía (p=0,04). A interacção da PON1 192 RR e da MTHFR 1298 AA, polimorfismos sedeados em genes diferentes, apresentou um risco relativo de DAC de 2,76 (OR=2,76;IC=1,20- 6,47; P=0,009), bastante superior ao risco de cada polimorfismo isolado, assim como a associação da PON1 RR + ECA DD (com polimorfismos também sedeados em genes diferentes), que apresentou um risco 337% superior relativamente aos que não possuíam esta associação (OR=4,37;IC=1,47- 13,87; P=0,002). Da mesma forma a associação entre a PON1 RR e ECA 8 GG, revelou um risco ainda mais elevado (OR=6;23; IC=1,67- 27,37; P<0,001). Após modelo de Regressão Logística as variáveis que ficaram na equação representando factores de risco significativos e independentes para DAC, foram os hábitos tabágicos, doença familiar, diabetes, fibrinogénio, Lp (a) e a associação PON1 192 RR + ECA 8 GG. Esta última associação apresentou, na regressão logística, um OR=14,113; p=0,018 Conclusões: O genótipo PON1 192 RR apresentou, se avaliado isoladamente, um risco relativo de DAC 80% superior relativamente à população que não possuía este genótipo. A associação deste polimorfismo com outros polimorfismos sedeados em genes diferentes, codificando para diferentes enzimas e pertencendo a sistemas fisiopatológicos distintos (MTHFR1298 AA, ECA DD e ECA 8 GG), aumentou sempre o risco de eclosão da DAC. Após correcção para os outros factores de risco clássicos e bioquímicos, a associação PON1 192 RR + ECA 8 GG, continuou a ser um factor de risco significativo e independente para CAD.
- RAS gene polymorphisms, classical risk factors and the advent of coronary artery disease in the Portuguese populationPublication . Freitas, Ana I.; Mendonça, Isabel; Brión, Maria; Sequeira, Miguel M.; Reis, Roberto P.; Carracedo, Angel; Brehm, AntónioBackground: Several polymorphisms within the renin-angiotensin system cluster of genes have been associated with the advent of coronary artery disease (CAD) or related pathologies. We investigated the distribution of 5 of these polymorphisms in order to find any association with CAD development and distinguish if any of the biochemical and behavioural factors interact with genetic polymorphisms in the advent of the disease. Methods: ACE I/D (rs4340), ACE A11860G (rs4343), AT1R A1166C (rs5186), AGT T174M (rs4762) and AGT M235T (rs699) gene polymorphisms were PCR-RFLP analysed in 298 CAD patients and 510 controls from Portugal. Several biochemical and behavioural markers were obtained. Results: ACE I/D DD and ACE11860 GG genotypes are risk factors for CAD in this population. The simultaneous presence of ACE I/D I and ACE11860 A alleles corresponds to a significant trend towards a decrease in CAD incidence. We found several synergistic effects between the studied polymorphisms and classical risk factors such as hypertension, obesity, diabetes and dyslipidaemia: the presence of the DD genotype of ACE I/D (and also ACE11860 GG) increases the odds of developing CAD when associated to each one of these classical risk factors, particularly when considering the male and early onset CAD subgroup analysis; AGT235 TT also increases the CAD risk in the presence of hypertension and dyslipidaemia, and AT1R1166 interacts positively with hypertension, smoking and obesity. Conclusion: ACE polymorphisms were shown to play a major role in individual susceptibility to develop CAD. There is also a clear interaction between RAS predisposing genes and some biochemical/environmental risk factors in CAD onset, demonstrating a significant enhancement of classical markers particularly by ACE I/D and ACE11860.
- A simple emulsification-assisted extraction method for the GC–MS/SIM analysis of wine markers of aging and oxidation: application for studying micro-oxygenation in Madeira WinePublication . Freitas, Ana I.; Pereira, Vanda; Leça, João M.; Pereira, Ana C.; Albuquerque, Francisco; Marques, José C.Sotolon and the heterocyclic acetals of glycerol are known as potential aging and oxidation markers in fortified wines such as Madeira, Port, and Sherry. Thus, determining the evolution of these compounds under different oxidative aging conditions is important for fortified wine quality purposes. This study proposes a new methodology based on a miniaturized emulsification extraction followed by GC–MS/SIM, which was developed and optimized to follow the formation of sotolon and heterocyclic acetals in fortified wines that were submitted to traditional accelerated aging and micro-oxygenation. The optimization was achieved by means of a mixed-level factorial design, considering 3 factors: sample volume, extractant volume, and concentrated extract volume, by performing 19 experiments in duplicate. The extraction was optimized using 8 mL of wine sample, 5 mL of dichloromethane, concentrating the extract up to 10-fold. The method performance was evaluated for sotolon, using a matrix matched calibration between 10 and 2000 μg/L. The selectivity was confirmed through the analysis of real samples. The methodology showed good linearity (R2 = 0.999), high sensitivity (LOQ = 6.8 μg/L), recovery about 105%, and good precision (less than 8 and 9%, evaluated by the variation of intra- and inter-day measurements, respectively). This is the first methodology that revealed to be an excellent tool to simultaneously follow the formation of sotolon and heterocyclic acetals in Madeira wines, using an inexpensive, simple, efficient, and effective experimental layout. Indeed, it was shown that traditional accelerated aging and micro-oxygenation have impact on the formation of such molecules.
- Unveiling the evolution of Madeira Wine key metabolites: a three-year follow-up studyPublication . Pereira, Vanda; Leça, João M.; Freitas, Ana I.; Pereira, Ana C.; Pontes, Marisela; Albuquerque, Francisco; Marques, José C.Madeira wine (MW) encompasses an unusual oxidative ageing process that makes it distinc tive. Several metabolites have been related to its quality and safety, such as 5-hydroxymethylfurfural (HMF), furfural, sotolon, and ethyl carbamate (EC). These compounds were quantified over a three year period to assess their formation rate according to the ageing procedure used: canteiro vs. estufagem. Estufagem, which includes thermal processing of young MWs, promoted greater HMF, furfural, and sotolon accumulation, especially in sweet wines, in which sotolon contributed significantly to aroma (odour active values up to 17.5). Tinta Negra revealed a higher predisposition to form EC while Malvasia and Sercial were less prone to its formation. The formation of furfural, HMF, and EC strongly correlated with the ageing time. Sotolon had a strong correlation with the ageing time in canteiro (r = 0.79) and a moderate correlation in estufagem (r = 0.65). In both ageing procedures, sotolon, furfural, and HMF formation trends strongly correlated with each other (r = 0.74–0.90). In turn, EC also correlated with all furans (r = 0.51–0.85). Yellow tones (b*) correlated with these metabolites only when wines undergo estufagem. This study provides valuable insights to improve MW quality and safety management procedures.