Browsing by Author "Ferreira, Miguel"
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- Characterization of the aroma and colour profiles of fortified Muscat wines: comparison of Muscat Blanc “à petit grains” grape variety with Red MuscatPublication . Jesus, Diva; Campos, Francisco M.; Ferreira, Miguel; Couto, José A.Although Muscat Blanc “à petit grains” and Red Muscat grape varieties are both cultivated in the Douro Demarcated Region (Portugal), only Muscat Blanc is currently authorized for the production of the fortified wine “Moscatel do Douro”. The aim of this study was to evaluate the potential of the Red Muscat grape variety to be employed in the winemaking of Douro Muscat wines. Wines of both grape varieties were produced from the 2013 and 2014 harvests, and were chemically and sensory analysed 12 and 3 months after stopping the alcoholic fermentation, respectively. The Muscat Blanc “à petit grains” variety produced musts with higher sugar content than the red variety, but the final levels of sugar and ethanol were similar in all wines owing to the control of the fermentation time. Red Muscat wines presented higher concentrations of rose oxide and nerol than Muscat Blanc “à petit grains”; however, these differences were only significant in the youngest wines. Linalool and α-terpineol were found at higher levels in the 2013 Muscat Blanc “à petit grains” wines. No significant differences were found for the ester compounds, except for 2-phenylethanol, which was higher in the Red Muscat wines. The 12 months old wines presented a higher total concentration of esters than the younger wines. No significant differences were found for the higher alcohols composition between the two grape varieties. The chromatic analysis showed that, besides having a redder tone, Red Muscat wines had a higher colour intensity and a more pure/saturated colour than Muscat Blanc “à petit grains” wines. The sensory analysis did not detect significant differences in the aromatic and gustatory profiles between the two grape varieties. The Red Muscat grape variety shows great potential to be employed in the production of Muscat fortified wine either as monovarietal or in blends with Muscat Blanc “à petit grains”.
- Searching for Better 3D Baseline StimuliPublication . Silva, Manuel; Teixeira, Luis Miguel Lopes; Ferreira, Miguel; Oliveira-Silva, PatriciaThe use of accurate and appropriate physiological baseline procedures is essential in experimental paradigms in the field of neuroscience. However, the most challenging parts of designing a new study for experimental laboratory studies, especially when using psychophysiological measures, is the choice of the appropriate stimuli for the baseline or control task, in order to compute reactivity. This study aimed to select and validate the most suitable image category to be used as a baseline task, through self-report and physiological measures. The images were selected according to a previous baseline, but adding the 3D and virtual world component, which is the foundation of our experiment. An experiment comprising a number of visual stimuli (15 images) in a virtual world using a Virtual Reality system, in which we assessed valence and arousal through self-report measures after visualizing each stimulus. Our discussion will emphasize the challenges involved in choosing an appropriate type of stimuli for baseline tasks and suggest that caution is never wasted.
- Validation of psychophysiological measures for caffeine oral films characterization by machine learning approachesPublication . Batista, Patrícia; Rodrigues, Pedro Miguel; Ferreira, Miguel; Moreno, Ana; Silva, Gabriel; Alves, Marco; Pintado, Manuela; Oliveira-Silva, PatríciaBackground: The oral films are a new delivery system that can carry several molecules, such as neuromodulator molecules, including caffeine. These delivery systems have been developed and characterized by pharmacokinetics assays. However, new methodologies, such as psychophysiological measures, can complement their characterization. This study presents a new protocol with psychophysiological parameters to characterize the oral film delivery systems based on a caffeine model. (2) Methods: Thirteen volunteers (61.5% females and 38.5% males) consumed caffeine oral films and placebo oral films (in different moments and without knowing the product). Electrocardiogram (ECG), electrodermal (EDA), and respiratory frequency (RF) data were monitored for 45 min. For the data analysis, the MATLAB environment was used to develop the analysis program. The ECG, EDA, and RF signals were digitally filtered and processed, using a windowing process, for feature extraction and an energy mean value for 5 min segments. Then, the data were computed and presented to the entries of a set of Machine Learning algorithms. Finally, a data statistical analysis was carried out using SPSS. (3) Results: Compared with placebo, caffeine oral films led to a significant increase in power energy in the signal spectrum of heart rate, skin conductance, and respiratory activity. In addition, the ECG time-series power energy activity revealed a better capacity to detect caffeine activity over time than the other physiological modalities. There was no significant change for the female or male gender. (4) Conclusions: The protocol developed, and the psychophysiological methodology used to characterize the delivery system profile were efficient to characterize the drug delivery profile of the caffeine. This is a non-invasive, cheap, and easy method to apply, can be used to determine the neuromodulator drugs delivery profile, and can be implemented in the future.