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- 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.
- New insights into ethyl carbamate occurrence in fortified winesPublication . Leça, João M.; Pereira, Vanda; Miranda, Andreia; Vilchez, José Luis; Marques, José C.The occurrence of ethyl carbamate (EC) in fortified wines was studied testing different model wines under accelerated ageing (45 °C for 4 months and 70 °C for 1 month), to investigate the possibility of arginine (Arg) being a direct precursor of EC in fortified wines, comparing it with known major precursors, urea and citrulline (Cit). Wine main sugars were appraised as possible catalysts, as previously pointed out. Model wines showed that: Arg can induce the EC formation under accelerated ageing, even without being metabolised by microorganisms; although much less reactive, Arg can play a significant role since high residual levels can occur in young fortified wines; glucose (Glc) and fructose (Fru) suppressed the EC formation from urea and Cit pathways, in about 11–26%. Moreover, Madeira wine samples were investigated in order to appraise the eventual contribution of the alcoholic fortification. The results revealed that this step can promote a decrease of the amount of these EC precursors up to 46%. Despite preliminary, additional information about the EC formation in fortified wines was obrained namely for designing new mitigation strategies, which can pass through the reduction of residual Arg.
- Influence of crop system fruit quality, carotenoids, fatty acids and phenolic compounds in cherry tomatoesPublication . Fernandes, Igor; Leça, João M.; Aguiar, Roberto; Fernandes, Tomásia; Marques, José C.; Cordeiro, NereidaTomato is one of the most consumed vegetables in the world, and its intake is known to be beneficial for human health. The nutritional quality of tomato is connected with numerous factors namely the cultivation system. To achieve the highest fruit quality and yield, the cherry tomato (Lycopersicon esculentum Mill. var. Moscatel RZ) was cultivated in three cultivation systems and its nutritional quality was evaluated. The highest fruit productivity, 2135–2240 g plant-1 dry weight (dw), was observed for the cherry tomatoes grown in the soilless systems. The cherry tomato from the hydroponic culture had the highest protein (13.41% dw), lipid (3.20% dw), sugar (354.94 mg g-1 dw) and taste index (1.24). It also comprised high amounts of monounsaturated and polyunsaturated fatty acids, like oleic (1.28 mg g-1 dw) and linoleic acids (5.42 mg g-1 dw). With respect to cherry tomato from the organic culture, higher contents of carotenoids—lycopene (47.1 mg kg-1 dw) and polyphenols (56.7 mg GAE 100 g-1 dw) were verified. Flavonoids were the main family of phenolic compounds found in the cherry tomato. The highest levels of chalconaringenin (51.95 mg 100 g-1 dw) and rutin (39.69 mg 100 g-1 dw) were observed in the cherry tomatoes cultivated through organic practices. This study shows that the agronomic system greatly influences the different characteristics associated with fruit quality. Hydroponic cultures presented higher quality, namely texture and taste, while the higher amounts of bioactive compounds were found in the organic culture.