Artigos em revistas internacionais
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- Influence of cold pre-fermentation maceration on the volatilomic pattern and aroma of white winesPublication . Alti-Palacios, Laura; Martínez, Juana; Teixeira, José A. C.; Câmara, José S.; Perestrelo, Rosa; Câmara, José; Perestrelo, RosaAroma compounds play a key role in wine quality due to their importance in wine aroma. The aim of the present study is to investigate the influence of cold pre-fermentative maceration (CPM) treatment on aromatic and sensory properties of white wines from four grape varieties (Tempranillo Blanco, Maturana Blanca, Viura and Garnacha Blanca) during two consecutive years (2019 and 2020). A total of 62 aroma compounds belonging to different chemical families were identified using headspace solid-phase microextraction combined with gas chromatography mass spectrometry (HS-SPME/GC-MS). CPM treatment enhanced the total relative concentration of alcohols, esters and acids compared to control wines. Regarding sensorial properties, esters made the greatest contribution to the studied white wines, mainly through the development of floral and fruity notes. On the other hand, CPM treatment did not significantly influence the total relative concentration of terpenoids, and different trends were observed according to grape variety and vintage. The obtained results showed differences in the wine’s aromatic complexity according to the grape variety, the vintage and the treatment applied and suggested that CPM treatment could represent a suitable approach to manipulate the aromatic profile and enhance the aromatic quality and complexity of wine.
- An improved analytical approach based on µ-QuEChERS combined with LC-ESI/MS for monitoring the occurrence and levels of Patulin in commercial apple juicesPublication . Câmara, José S.; Fernandes, Paulo; Barros, Nelson; Perestrelo, Rosa; Câmara, José; Perestrelo, RosaPatulin (PAT) is a mycotoxin produced in fruits, especially in apples, by diverse fungal species that can be transferred into industrial apple juice during processing. An accurate, effective, and selective method has been validated for the quantification of PAT in different commercial apple juices by combining a modified µ-QuEChERS procedure with high-pressure liquid chromatography (LC) equipped with a triple quadrupole mass spectrometer (QqQMS). This sample extraction procedure reduced interference from the sugar-rich matrix, and the separation was performed using the C18 Atlantis T3 column within 10 min. PAT was found by MS with electrospray negative ionization (ESI−) in the mode of multiple reaction monitoring (MRM). The correlation coefficient (R2 = 0.999) satisfied the prerequisite of linearity for PAT in the concentration range of 2–50 μg/kg. The limits of detection (LOD) and quantification (LOQ) of PAT were 0.32 and 1.15 μg/kg, respectively, which were compliant with the maximum levels settled in Commission Regulation (EC) No. 1881/2006. The recoveries were within the 92–103% range, at three fortified levels of 2, 20 and 50 μg/kg, with relative standard deviations lower than 7%. Based on analytical validation, it was confirmed that the µ-QuEChERS/HPLC-MS/MS method is an enhanced, reliable, and quick approach for determination of PAT in apple juice. The current approach proposes reduced sample preparation and analysis time. In addition, it is economical, environmentally friendly, and simpler to implement in comparison to traditional approaches.
- Evaluation of the transfer and occurrence of opium alkaloids in poppy seed teas using preconcentrations with µSPEed® followed by GC-MS analysisPublication . Casado-Hidalgo, Gema; Perestrelo, Rosa; Morante-Zarcero, Sonia; Câmara, José S.; Sierra, Isabel; Câmara, José; Perestrelo, RosaIntoxication due to the consumption of poppy seed teas has been reported due to their contamination with opium alkaloids (OAs). In this work, an efficient methodology based on microsolid-phase extraction (µSPEed®) followed by gas chromatography–mass spectrometry (GC-MS) has been optimized to quantify five OAs in poppy seed teas. Nine cartridges (C4, C8, C18, silica, APS, PFAs, PS/DVB-RP, PS/DVB-SCX and PS/DVB-SAX), pH levels, cycles and elution solvents were evaluated. The method was validated and applied to study the transfer of OAs by evaluating water temperatures, infusion times and seed amounts. The highest transfer rates (71% for morphine, 96% for thebaine, and 100% for codeine, noscapine and papaverine) were achieved at 90°C, 5 min, with 4 g. These conditions were used to quantify the OAs in four teas prepared from different seeds. A high amount of morphine (1563 µg/L) was found in one tea, indicating that the seeds had a concentration twice the maximum limit, highlighting the need to warn the population of this dangerous practice.
- Bioactive compounds and antioxidant activity from spent coffee grounds as a powerful approach for Its valorizationPublication . Andrade, Carolina; Perestrelo, Rosa; Câmara, José S.Coffee is one of the world’s most popular beverages, and its consumption generates copious amounts of waste. The most relevant by-product of the coffee industry is the spent coffee grounds, with 6 million tons being produced worldwide per year. Although generally treated as waste, spent coffee grounds are a rich source of several bioactive compounds with applications in diverse industrial fields. The present work aimed at the analysis of spent coffee grounds from different geographical origins (Guatemala, Colombia, Brazil, Timor, and Ethiopia) for the identification of bioactive compounds with industrial interest. For this purpose, the identification and quantification of the bioactive compounds responsible for the antioxidant activity attributed to the spent coffee grounds were attempted using miniaturized solid-phase extraction (µ-SPEed), combined with ultrahigh-performance liquid chromatography with photodiode array detection (UHPLC-PDA). After validation of the µ-SPEed/UHPLC-PDA method, this allowed us to conclude that caffeine and 5-caffeoylquinic acid (5-CQA) are the most abundant bioactive compounds in all samples studied. The total phenolic content (TPC) and antioxidant activity are highest in Brazilian samples. The results obtained show that spent coffee grounds are a rich source of bioactive compounds, supporting its bioprospection based on the circular economy concept closing the loop of the coffee value chain, toward the valorization of coffee by-products.
- Spices volatilomic fingerprinting: a comprehensive approach to explore its authentication and bioactive propertiesPublication . Izcara, Sergio; Perestrelo, Rosa; Morante-Zarcero, Sonia; Sierra, Isabel; Câmara, José S.; Perestrelo, Rosa; Izcara Sierra, SergioVolatile organic metabolites (VOMs) present in different spices can provide distinct analytical biosignatures related to organoleptic properties and health benefits. This study aimed to establish the volatilomic fingerprint of six of the most consumed spices all over the world (saffron (Crocus sativus L.), cinnamon (Cinnamomum verum), cumin (Cuminum cyminum L.), black pepper, (Piper nigrum L.), sweet paprika (Capsicum annuum L.), and curry (a mix of different herbs and spices)). Based on headspace solid phase microextraction (HS-SPME) followed by gas chromatography-mass spectrometry (GC-MS) analysis, this is a powerful strategy to explore and establish the spice’s volatile pattern and unravel the potential health benefits related to the most important VOMs identified in each spice. This comprehensive knowledge will help in the definition of their authenticity, while simultaneously protecting against potential frauds and adulterations. A total of 162 VOMs were identified. Semi-quantitative assessments revealed that terpenoids and sesquiterpenoids amounted to the major volatile class in the investigated spices, except for cinnamon, where carbonyl compounds are the major group. Most of the studied spices comprised key characteristics of aroma and health bioactive compounds, e.g., dihydrojuneol in saffron, cinnamaldehyde in cinnamon, cuminaldehyde in cumin and curry, and caryophyllene in black pepper. The principal component analysis (PCA) and partial least-squares discriminant analysis (PLS-DA) successfully discriminated the investigated spices, being α-cubebene, 3-methyl butanal, β-patchoulene and β-selinene, the most important VOMs (highest VIP’s) that contributed to its discrimination. Moreover, some VOMs have a high influence on the spice’s bioactive potential, helping to prevent certain diseases including cancer, inflammatory-related diseases, diabetes, and cardiovascular diseases.
- Real-time measurement of refractive index using 3D-printed optofluidic fiber sensorPublication . Leça, João M.; Magalhães, Yannis; Antunes, Paulo; Pereira, Vanda; Ferreira, Marta S.; Leça, João MicaelThis work describes a 3D-printed optofluidic fiber sensor to measure refractive index in real time, combining a microfluidic system with an optical fiber extrinsic Fabry–Perot interferometer. The microfluidic chip platform was developed for this purpose through 3D printing. The Fabry–Perot cavity was incorporated in the microfluidic chip perpendicularly to the sample flow, which was of approximately 3.7 µL/s. The optofluidic fiber sensor platform coupled with a low-cost optical power meter detector was characterized using different concentrations of glucose solutions. In the linear regression analysis, the optical power shift was correlated with the refractive index and a sensitivity of −86.6 dB/RIU (r2 = 0.996) was obtained. Good results were obtained in terms of stability with a maximum standard deviation of 0.03 dB and a sensor resolution of 5.2 × 10−4 RIU. The feasibility of the optofluidic fiber sensor for dynamic analyses of refractive index with low sample usage was confirmed through real-time measurements.
- Optical fiber sensor for monitoring the evaporation of ethanol–water mixturesPublication . Pereira, Diana; Bierlich, Jörg; Kobelke, Jens; Pereira, Vanda; Ferreira, Marta S.; Pereira, VandaAn inline optical fiber sensor is proposed to monitor in real time the evaporation process of ethanol–water binary mixtures. The sensor presents two interferometers, a cladding modal interferometer (CMI) and a Mach–Zehnder interferometer (MZI). The CMI is used to acquire the variations in the external medium refractive index, presenting a maximum sensitivity of 387 nm/RIU, and to attain the variation in the sample concentration profile, while the MZI monitors temperature fluctuations. For comparison purposes, an image analysis is also conducted to obtain the droplet profile. The sensor proposed in this work is a promising alternative in applications where a rigorous measurement of volatile organic compound concentrations is required, and in the study of chemical and physical properties related to the evaporation process.
- Transforming education: pedagogical innovation in diversifed contextsPublication . Fonseca, Arnaldo; Dinis Fonseca, Arnaldo JoséThe research presented follows an interpretative, organized, and systematic pro cess aimed at the emergence of concepts and practices capable of deepening the understan ding of Pedagogical Innovation (PI) across diverse formal, non-formal, and informal learning environments. Conceptually, Peda gogical Innovation is analyzed within a post modern context, where epistemological and axiological challenges increasingly impact education, particularly schools, which often remain anchored in practices that struggle to foster deep and meaningful learning of an ever more plural, intersubjective, and complex knowledge landscape. The research employs an interpretative meta-synthesis approach, analyzing 107 dissertations and theses in Edu cational Sciences—Pedagogical Innovation, defended at the University of Madeira betwe en 2007 and 2015. All studies analyzed were qualitative, and the meta-synthesis utilized a meta-ethnographic methodology. Through an inductive process, the research structured successive interpretative syntheses in its first stage, identifying 1,285 conceptual segments that reflect ideas, concepts, or topics relevant to the theme. In the second stage, involving the translation of primary studies (1st Level of Synthesis), 42 significant key concepts were identified. This process culminated in the third stage—Synthesis of Translations (2nd Level of Synthesis)—which led to the forma tion of five macro-conceptual categories: the construction of competences, teaching profes sionalism, students’ learning experiences, the nature of praxis, and instrumental resources. The conclusions reveal that Pedagogical Innovation constitutes a complex and multidimen sional phenomenon rooted in conscious and critical processes of change. These processes emphasize students’ capacities and attitudes, linked to pedagogical practices grounded in constructivist epistemological frameworks. Additionally, the findings highlight an inno vative praxis that remains deeply localized, limited to micro-intervention environments. The potential of ICT is noted as a valuable tool for fostering new learning approaches under specific conditions. Recommendations are directed at educational institutions, urging them to act as facilitators of collaborative cultural spaces, and at policymakers, advocating for strategies to reduce bureaucratic constraints and enable genuine school autonomy.
- The impact of questioning on classroom dynamics: a critical analysisPublication . Fonseca, Arnaldo; Dinis Fonseca, Arnaldo JoséThis article critically examines the impact of questioning on classroom dyna mics, restructuring and deepening the un derstanding of its role as a fundamental ca talyst for learning environments intended to be dynamic, collaborative, and particularly student-centered. Through a comprehensive review of the literature, the article discusses how intentional and strategic questioning can foster critical thinking, intellectual curiosity, student autonomy, and metacognitive skills. In this regard, active learning methodologies are addressed, with emphasis on Problem-Ba sed Learning (PBL), the Socratic method, and Inquiry-Based Learning (IBL), highlighting the transformative potential of the teacher’s role as a facilitator. Additionally, contempo rary challenges are explored alongside emer ging opportunities, particularly the impact of Artificial Intelligence (AI) on the promotion and development of questioning and critical thinking. The conclusion is that questioning, beyond a mere pedagogical technique, cons titutes an indispensable competence for the holistic development of autonomous, critical citizens prepared for the challenges of a cons tantly transforming world, thus requiring a continuous recalibration of pedagogical priorities and teacher training.
- Analysis of the environmental impact of botanical pesticides in soilPublication . Pereira, Verónica; Castilho, Paula C.; Pereira, Jorge A. M.; Augusto Machado Pereira, JorgePlant-based pesticides are considered viable complements of conventional synthetic pesticides in agriculture. Their environmentally benign nature and potential to mitigate ecological impacts render them advantageous options for sustainable farming practices. However, the long-term effects of botanical pesticides on soil ecosystems remain unclear. This review aims to examine current evidence concerning the persistence of botanical pesticides in soil environments and their potential effects. Specifically, it addresses their biodegradation pathways in soil as well as their impact on soil enzymes and biology. The methodologies available to perform these studies are also briefly discussed, particularly focusing on how they can be tailored to improve the analysis of the impacts and challenges posed by the use of botanical pesticides in ecosystems.