3-Hydroxy-4, 5-dimethyl-2 (5 H)-furanone levels in fortified Madeira wines: Relationship to sugar content

The maturation of Madeira wines usually involves exposure to relatively high temperatures and humidity levels >70%, which affect the aroma and flavor composition and lead to the formation of the typical and characteristic bouquet of these wines. To estimate the levels of sotolon [3-hydroxy4,5-dimethyl-2(5 H )-furanone] and their behavior over time, 86 aged Madeira wines samples (1-25 years old), with different sugar concentrations, respectively, 90 g L-1 for Boal, 110 g L-1 for Malvazia, 25 g L -1 for Sercial, and 65 g L-1 for Verdelho varieties, were analyzed. Isolation was performed by liquid-liquid extraction with dichloromethane followed by chromatographic analysis by GC-MS. The reproducibility of the method was found to be 4.9%. The detection and quantification limits were 1.2 and 2.0 µgL-1, respectively. The levels of sotolon found ranged from not detected to 2000 µgL-1 for wines between 1 and 25 years old. It was observed that during aging, the concentration of sotolon increased with time in a linear fashion ( r ) 0.917). The highest concentration of sotolon was found in wines with the highest residual sugar contents, considering the same time of storage. The results show that there is a strong correlation between sotolon and sugar derivatives: furfural, 5-methylfurfural, 5-hydroxymethylfurfural, and 5-ethoxymethylfurfural. These compounds are also well correlated with wine aging. These findings indicate that the kinetics of sotolon formation is closely related with residual sugar contents, suggesting that this molecule may come from a component like sugar.

O insucesso no ensino superior: perspectivas e situação dos alunos do 4º ano via ensino da Universidade da Madeira

De acordo com um estudo do Observatório da Ciência e Ensino Superior (OCES), sobre taxas de insucesso no ensino Superior relativas ao ano lectivo de 2002/03, cerca de 1/3(36.5%) dos estudantes do ensino Universitário não termina o curso no tempo previsto.Já no Ensino Politécnico, os números são mais elevados, com um índice de insucesso de 46%. Na Universidade da Madeira a taxa de insucesso no ano lectivo de 2002/03 foi de 42.3%, superior à média nacional das Universidades (36.5%). De um total de 642 alunos inscritos pela 1ª vez no 1º ano, apenas 370 concluíram os seus cursos no tempo normal. Dados mais recentes (2004/05), indicam uma taxa de insucesso de 45.1%; de um total de inscritos de 459 no ano lectivo de 2001/02, somente 252 terminaram os seus cursos no ano lectivo de 2004/05. Este estudo de investigação levado a cabo junto dos alunos do 4º ano, via ensino, da Universidade da Madeira pretende averiguar das razões do insucesso académico a nível universitário, determinar possíveis diferenças de género e investigar sugestões para a diminuição das elevadas taxas de insucesso.