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- Sustainable use of wood in wine spirit productionPublication . Canas, Sara; Caldeira, Ilda; Fernandes, Tiago; Anjos, Ofélia; Belchior, António Pedro; Catarino, SofiaA comprehensive overview of the sustainability of wood-based technologies for the production of high-quality and differentiated wine spirits, and the research carried out in this field is provided in this chapter. Barrels are actively involved in the wine spirit's composition and sensory changes due to the transfer of oxygen, and extractive compounds from wood to the beverage. The key physicochemical phenomena and determining factors at the aging stage are illustrated with regard to the sustainable use of wood both in barrels and through innovative technologies for wine spirit's aging. A broad perspective is offered to readers on the fair and sustainable use and reuse of wood, the circular economy and its relationship with cooperage efficiency, including responsible relations/commitments in the entire value chain (from the forest to the aged wine spirit).
- Behaviour of low molecular weight compounds, iron and copper of wine spirit aged with chestnut staves under different levels of micro-oxygenationPublication . Canas, Sara; Danalache, Florina; Anjos, Ofélia; Fernandes, Tiago; Caldeira, Ilda; Santos, Nádia; Fargeton, Laurent; Boissier, Benjamin; Catarino, SofiaAlternative technologies for a more sustainable wine spirits’ ageing have been studied but a lack of knowledge on the effect of oxygenation level remains. This work examined the behaviour of low molecular weight compounds, iron and copper of a wine spirit aged in 50 L demijohns with chestnut wood staves combined with three levels of micro-oxygenation or nitrogen. Compounds and mineral elements were quantified by HPLC and FAAS, respectively, in samples collected at 8, 21, 60, 180, 270 and 365 days of ageing. Results showed that most of the compounds underwent significant changes in their content over time and behave differently depending on the wine spirit’s oxygenation level: higher contents of gallic acid, syringic acid and vanillin were associated with lower micro-oxygenation level while higher contents of ellagic acid, syringaldehyde, coniferaldehyde and sinapaldehyde resulted from higher one; lowest contents of these compounds were found in the nitrogen modality. Weak correlation between copper and the studied compounds was evidenced whereas closer relationship between iron, vanillin, gallic, syringic and ellagic acids at end of ageing was observed. This study provides innovative information on the role of oxygen in wine spirit’s ageing, and on chestnut wood effect on wine spirit’s mineral composition.
- Identification of gallotannins and ellagitannins in aged wine spirits: a new perspective using alternative ageing technology and high-resolution mass spectrometryPublication . Fernandes, Tiago; Antunes, Alexandra M. M.; Caldeira, Ilda; Anjos, Ofélia; Freitas, Victor de; Fargeton, Laurent; Boissier, Benjamin; Catarino, Sofia; Canas, SaraThis research was focused on identifying gallotannins and ellagitannins degradation pathways to better understand their behavior in complex media such as wine spirits (WS). A WS was aged with chestnut wood staves with three levels of micro-oxygenation, nitrogen, and using wooden barrels. Gallotannins and ellagitannins were identified by LC-ESI-HRMS/MS using a Q-TOF in samples collected at 8, 21, 60, 180, 270, and 365 days of ageing, allowed comparing their relative abundances according to the ageing technology. It was established for the first time, the importance of oxygen in gallotannins and ellagitannins formation/degradation pathways in WS and shading light into the explanation for the steady increase of gallic and ellagic acid contents on WS during ageing. The results also highlighted the presence of penta-O-galloyl-β-D-glucose, tetra-O-galloyl-β-D-glucose, tri- O-galloyl-β-D-glucose, di-O-galloyl-β-D-glucose, and mono-O-galloyl-β-D-glucose, 2,3-(S)-hexahydroxydiphenoyl- β-D-glucose, pedunculagin, isomers vescalagin/castalagin and two products stemming from ethanol-promoted oxidation of castalagin/vescalagin and vescalin/castalin, in the composition WS aged with chestnut wood.
- Influence of the storage in bottle on the antioxidant activities and related chemical characteristics of wine spirits aged with chestnut staves and micro-oxygenationPublication . Alves, Sheila Cristina Oliveira; Lourenço, Sílvia; Anjos, Ofélia; Fernandes, Tiago; Caldeira, Ilda; Catarino, Sofia; Canas, SaraDifferent ageing technology of wine spirits (WSs) has been investigated, but little has been published on the chemical evolution of aged WS during storage in bottle. The purpose of this study was to examine how 12 months of storage in bottle affected the evolution of antioxidant activity (DPPH, FRAP and ABTS assays), total phenolic index (TPI) and low molecular weight (LMW) compounds content of the WSs aged through alternative technology using three micro-oxygenation levels (MOX) and nitrogen control (N). Results revealed the ability of phenolic compounds from aged WSs to scavenge free radicals during storage in bottle. Among the in vitro antioxidant-activity methods, FRAP assay was the more effective to differentiate WSs according to the ageing technology. Concerning the overall influence of storage in bottle on antioxidant activity, and TPI and LMW compounds content, the higher results were obtained for the MOX modalities (O15, O30 and O60), which showed a similar evolution. In summary, this study provides innovative information, demonstrating that the differences between the aged WSs imparted throughout the ageing process (resulting from different MOX levels) were mostly retained, and only slight modifications during storage in bottle were found.
- Micro-oxygenation level as a key to explain the variation in the colour and chemical composition of wine spirits aged with chestnut wood stavesPublication . Canas, Sara; Anjos, Ofélia; Caldeira, Ilda; Fernandes, Tiago; Santos, Nádia; Lourenço, Sílvia; Soares, Joana Granja; Fargeton, Laurent; Boissier, Benjamin; Catarino, SofiaChemistry and to select the most suitable technological option towards quality and sustainability. Following two articles on the same trial, this work focused on colour, total phenolic index (TPI) and basic chemical characteristics of a wine spirit aged in 50 L demijohns with chestnut wood staves together with three micro-oxygenation (MOX) levels. Chromatic characteristics and TPI were monitored over time (8–365 days) while sensory colour, alcoholic strength, acidity, pH and dry extract were assessed at the end of ageing. Results showed that stronger oxygenation promoted significantly faster colour evolution (lower lightness, higher chroma, red, yellow and brown hues) and higher TPI than mild and intermediate oxygenation until 60 days, probably by favouring the leaching of outer wood layers and extraction/degradation of tannins. No significant differences were found between these ageing modalities at 365 days. Outcomes suggest that the stronger MOX is the most suitable modality in terms of quality and sustainability. Significant differences between wine spirits resulting from MOX and control modality (slower colour evolution, lower TPI and dry extract) confirms the oxygen pivotal role in wine spirit’s ageing, particularly in the colour evolution.
- Wine spirit ageing with chestnut staves under different micro-oxygenation strategies: effects on the volatile compounds and sensory profilePublication . Caldeira, Ilda; Vitória, Cláudia; Anjos, Ofélia; Fernandes, Tiago; Gallardo, Eugenia; Fargeton, Laurent; Boissier, Benjamin; Catarino, Sofia; Canas, SaraThe purpose of this work is to evaluate the wine spirit aged by an alternative process (staves combined with different micro-oxygenation levels) and its comparison with the traditional process (wooden barrels). This evaluation was made by analyzing the volatile compounds and sensory profile of the spirits during 365 days of ageing. The findings confirmed the role played by oxygen in the volatile profile of aged wine spirits. Samples of alternative ageing modalities were well distinguished from those of wooden barrels based on the volatile profile, namely on the concentrations of several volatile phenols. From a sensory point of view, the results are promising with high overall consistency scores obtained from samples of alternative ageing process modalities.
- Sisal-derived acid-char molybdenum catalyst for reductive deoxygenation of sulfoxidesPublication . Duarte, Tiago A. G.; Mestre, Ana S.; Ferreira, Maria J. G.; Rego, Ana M. Botelho do; Ferraria, Ana M.; Kirillova, Marina V.; Carvalho, Ana P.; Calhorda, Maria José; Fernandes, TiagoThe deoxygenation of sulfoxides is a rather important reaction from both synthetic and biological points of view, due to the potential of sulfides as intermediates in a variety of processes. Homogenous Mo-based catalysts successfully perform the reduction of diphenyl sulfoxide to diphenyl sulfide with high yields but present the well-known limitations regarding recovery and recycling. Thus, in the present work, two new supported catalysts were prepared through the immobilization of molybdenum precursor species (dichlorodioxodi(aquo)molybdenum(VI) and sodium molybdate), onto a sisal-derived acid-char (S13.5), obtained from rope industry wastes by acid-mediated carbonization. The heterogeneous Mo-based materials were characterized by IR spectroscopy, elemental analysis, ICP, solid state NMR, XPS, and SEM, and were evaluated as catalysts for the reduction of sulfoxides to sulfides in the presence of phenylsilane as reducing agent under different reaction conditions. The influence of various experimental parameters, including reducing agent type and amount, solvent type, and acid promoter were investigated. Catalytic studies revealed that both catalysts deoxygenate sulfoxides at 120 °C in toluene solution with high yields (up to 97%). The MoO2Cl2 derived catalyst shown to be highly efficient in the reduction of diaryl, alkylaryl, dibenzyl, and dialkyl sulfoxides to the corresponding sulfoxides using phenylsilane as reductant and no need of acid promoter.
- A avaliação: significado e consequênciasPublication . Fernandes, Tiago
- Perceptions of the students’ learning and evaluation process in an e-learning course in food preservation technology: a study case in a food consumption mscPublication . Fernandes, Tiago; Caetano, Fernando J. P.Food Preservation Technology is a main module within a course integrated in a Master of Science program in Food Consumption at Universidade Aberta, Portugal. The pedagogical model adopted at Universidade Aberta encourages open practices such as teamwork and participation at the forums for learning exchange. E-learning and b-learning tools are increasingly used in the actual global world, providing the students with a great opportunity to study from distance and submit their digital works or assignments for evaluation. However, in this case the distinctive evaluation of each student and classification with the respective grade may seem to be a significant problem for the teachers. During this module for each assignment topic, every student chose a different subject related to their professional or academic interests. This gives the student a chance to improve scientific knowledge within each topic and to further explore the proposed subject. Herein we have analysed how the different assignments that students completed within this module can reflect students’ commitment to study and actively seek for their own knowledge. Besides, the following points were also taken into consideration: (1) the difficulties that a teacher might have when evaluating students’ submitted assignments; (2) the tools that the teacher has to differentiate the quality of different assignments; as well as (3) the description of how grades can be differentiated between the students. The assignments were both teamwork and individual work that resulted from previous learning activities. In this paper, we have thus tried to understand the main limitations that students have to overcome while working on the evaluation assignments. The analytical data retrieved from the assignment’s forums reveal that only a very small part of information exchanged has a constructive nature and adds value to the work to be done. From the analysed data of the works presented by the students, it is evident that they did not use an accurate bibliographical state-of-the-art list. We also debate the teamwork evaluation process within the e-learning system and its relationship with the contemporary state-of-the-art of each discussed theme, namely Drying and water activity control, Chemical preservation, Curing, Pickling, Smoking, Fermentation, Modified atmosphere, High pressure processing, Ohmic heating, Irradiation, Membrane processing, Pulsed electric fields, and Microwave processing.
- PLS-R calibration models for wine spirit volatile phenols prediction by near-infrared spectroscopyPublication . Anjos, Ofélia; Caldeira, Ilda; Fernandes, Tiago; Pedro, Soraia; Vitória, Cláudia; Alves, Sheila Cristina Oliveira; Catarino, Sofia; Canas, SaraNear-infrared spectroscopic (NIR) technique was used, for the first time, to predict volatile phenols content, namely guaiacol, 4-methyl-guaiacol, eugenol, syringol, 4-methyl-syringol and 4-allyl-syringol, of aged wine spirits (AWS). This study aimed to develop calibration models for the volatile phenol’s quantification in AWS, by NIR, faster and without sample preparation. Partial least square regression (PLS-R) models were developed with NIR spectra in the near-IR region (12,500–4000 cm−1) and those obtained from GC-FID quantification after liquid-liquid extraction. In the PLS-R developed method, cross-validation with 50% of the samples along a validation test set with 50% of the remaining samples. The final calibration was performed with 100% of the data. PLS-R models with a good accuracy were obtained for guaiacol (r2 = 96.34; RPD = 5.23), 4-methyl-guaiacol (r2 = 96.1; RPD = 5.07), eugenol (r2 = 96.06; RPD = 5.04), syringol (r2 = 97.32; RPD = 6.11), 4-methyl-syringol (r2 = 95.79; RPD = 4.88) and 4-allyl-syringol (r2 = 95.97; RPD = 4.98). These results reveal that NIR is a valuable technique for the quality control of wine spirits and to predict the volatile phenols content, which contributes to the sensory quality of the spirit beverages.