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Sobre

Sobre

Colaboro no INESCTEC desde 2014, onde me encontro integrado no CAP | Centre for Applied Photonics. Como Químico de formação, tenho uma formação e experiência extensas em síntese, caracterização e (numa longa lista de) diversas técnicas laboratoriais, entre as quais as de determinação de propriedades fotofísicas. A minha experiência começou numa área mais focada na bioquímica com estudos relacionados com a saúde, com aplicações de suplementação animal para melhoria de propriedades e posteriormente com métodos de valorização de sub-produtos de indústria primária. No âmbito do 7th FP da UE (SNIFFER) ajudei no desenvolvimento de uma rede inteligente capaz de detectar ameaças tanto na cadeia alimentar como na prevenção de (bio)terrorismo. Foram desenvolvidos sensores bem como líquidos iónicos com diferentes propriedades, passíveis de serem usados como "pontes" a outros sensores ou estruturas sensitivas, ou de agirem como sensores eles próprios. No âmbito do CORAL, desenvolvi sensores para detecção de espécies químicas em meio aquoso (NO3-, NO2- e PO4-), com vista a criar condições para sustentabilidade social e económica na exploração marinha. Desenvolvi e ajudei a desenvolver o protótipo que resultou do projecto AGRINUPES que visava criar condições de sustentabilidade na exploração agrícola, nomeadamente através do uso sustentado de água e nutrientes; pelo desenvolvimento de tecnologia sensitiva capaz de determinar a sua concentração "in situ", desta forma assegurando uma fertilização adequada, promovendo economia ecológica e financeira. Actualmente encontro-me enquadrado no Smart Fertilizers, um projecto de Agricultura 4.0, que visa desenvolver espalhadores e cisternas inteligentes, com vista ao aumento da eficiência da operação de fertilização, para melhorias operacionais e competitivas.

Tópicos
de interesse
Detalhes

Detalhes

004
Publicações

2021

Antimicrobial Activity of Myrtus communis L. and Rosmarinus officinalis L. Essential Oils against Listeria monocytogenes in Cheese

Autores
Saraiva, C; Silva, AC; Garcia Diez, J; Cenci Goga, B; Grispoldi, L; Silva, AF; Almeida, JM;

Publicação
FOODS

Abstract
Listeria monocytogenes has been referred to as a concern microorganism in cheese making due to its ability to survive and grow in a wide range of environmental conditions, such as refrigeration temperatures, low pH and high salt concentration at the end of the production process. Since cheese may be a potential hazard for consumers, especially high-risk consumers (e.g., pregnant, young children, the elderly, people with medical conditions), efforts of the dairy industry have been aimed at investigating new conservation techniques based on natural additives to meet consumers' demands on less processed foods without compromising the food safety. Thus, the aim of this study was to evaluate the efficacy of Myrtus communis L. (myrtle) and Rosmarinus officinalis L. (rosemary) essential oils (EO) against Listeria monocytogenes ATCC 679 spiked in sheep cheese before ripening. After the cheesemaking process, the samples were stored at 8 degrees C for 2 h, 1 d, 3 d, 14 d and 28 d. The composition of EO was identified by gas chromatography-mass spectrometry (GC-MS) analysis. Constituents such as 1,8-cineole, limonene, methyl-eugenol, alpha-pinene, alpha-terpineol, alpha-terpinolene and beta-pinene were present in both EO, accounting for 44.61% and 39.76% from the total of chemical compounds identified for myrtle and rosemary EO, respectively. According to the chemical classification, both EO were mainly composed of monoterpenes. Minimum inhibitory concentration (MIC) against L. monocytogenes was obtained at 31.25 mu L/mL to myrtle EO and at 0.40 mu L/mL to rosemary EO. Then, cheeses were inoculated with L. monocytogenes (Ca. 6 log CFU/mL) and EO was added at MIC value. The addition of rosemary and myrtle EO displayed lower counts of L. monocytogenes (p < 0.01) (about 1-2 log CFU/g) during the ripening period compared to control samples. Ripening only influences (p < 0.001) the growth of L. monocytogenes in control samples. Since rosemary and myrtle EO do not exert any negative impact on the growth of native microflora (p > 0.05), their use as natural antimicrobial additives in cheese demonstrated a potential for dairy processors to assure safety against L. monocytogenes.

2021

Synthesis of Catechol Derived Rosamine Dyes and Their Reactivity toward Biogenic Amines

Autores
Monteiro Silva, F; Queiros, C; Leite, A; Rodriguez, MT; Rojo, MJ; Torroba, T; Martins, RC; Silva, AMG; Rangel, M;

Publicação
MOLECULES

Abstract
Functional organic dyes play a key role in many fields, namely in biotechnology and medical diagnosis. Herein, we report two novel 2,3- and 3,4-dihydroxyphenyl substituted rosamines (3 and 4, respectively) that were successfully synthesized through a microwave-assisted protocol. The best reaction yields were obtained for rosamine 4, which also showed the most interesting photophysical properties, specially toward biogenic amines (BAs). Several amines including n- and t-butylamine, cadaverine, and putrescine cause spectral changes of 4, in UV-Vis and fluorescence spectra, which are indicative of their potential application as an effective tool to detect amines in acetonitrile solutions. In the gas phase, the probe response is more expressive for spermine and putrescine. Additionally, we found that methanolic solutions of rosamine 4 and n-butylamine undergo a pink to yellow color change over time, which has been attributed to the formation of a new compound. The latter was isolated and identified as 5 (9-aminopyronin), whose solutions exhibit a remarkable increase in fluorescence intensity together with a shift toward more energetic wavelengths. Other 9-aminopyronins 6a, 6b, 7a, and 7b were obtained from methanolic solutions of 4 with putrescine and cadaverine, demonstrating the potential of this new xanthene entity to react with primary amines.

2021

Unravelling Plant-Pathogen Interactions: Proximal Optical Sensing as an Effective Tool for Early Detect Plant Diseases

Autores
Reis-Pereira, M; Martins, RC; Silva, AF; Tavares, F; Santos, F; Cunha, M;

Publicação
Chemistry Proceedings

Abstract
This study analyzed the potential of proximal optical sensing as an effective approach for early disease detection. A compact, modular sensing system, combining direct UV–Vis spectroscopy with optical fibers, supported by a principal component analysis (PCA), was applied to evaluate the modifications promoted by the bacteria Xanthomonas euvesicatoria in tomato leaves (cv. cherry). Plant infection was achieved by spraying a bacterial suspension (108 CFU mL-1) until run-off occurred, and a similar approach was followed for the control group, where only water was applied. A total of 270 spectral measurements were performed on leaves, on five different time instances, including pre- and post-inoculation measurements. PCA was then applied to the acquired data from both healthy and inoculated leaves, which allowed their distinction and differentiation, three days after inoculation, when unhealthy plants were still asymptomatic.

2021

Hydroponics Monitoring through UV-Vis Spectroscopy and Artificial Intelligence: Quantification of Nitrogen, Phosphorous and Potassium

Autores
Silva, AF; Löfkvist, K; Gilbertsson, M; Os, EV; Franken, G; Balendonck, J; Pinho, TM; Boaventura-Cunha, J; Coelho, L; Jorge, P; Martins, RC;

Publicação
Chemistry Proceedings

Abstract
In hydroponic cultivation, monitoring and quantification of nutrients is of paramount importance. Precision agriculture has an urgent need for measuring fertilization and plant nutrient uptake. Reliable, robust and accurate sensors for measuring nitrogen (N), phosphorus (P) and potassium (K) are regarded as critical in this process. It is vital to understand nutrients’ interference; thusly, a Hoagland fertilizer solution-based orthogonal experimental design was deployed. Concentration ranges were varied in a target analyte-independent style, as follows: [N] = [103.17–554.85] ppm; [P] = [15.06–515.35] ppm; [K] = [113.78–516.45] ppm, by dilution from individual stock solutions. Quantitative results for N and K, and qualitative results for P were obtained.

2020

Behavior of Listeria monocytogenes in beef Sous vide cooking with Salvia officinalis L. essential oil, during storage at different temperatures

Autores
Moura Alves, M; Gouveia, AR; de Almeida, JMMM; Monteiro Silva, F; Silva, JA; Saraiva, C;

Publicação
LWT-FOOD SCIENCE AND TECHNOLOGY

Abstract
This study aims to evaluate the effect of Salvia officinalis L. (sage) essential oil (EO) on behavior of L. monocytogenes ATCC679 inoculated in beef processed by Sous-vide cook-chill (SVCC) and stored at 2 or 8 °C during 28 days. Minimum inhibitory concentration (MIC) of L. monocytogenes was obtained with 31.3 µL/mL of EO. D values were determined for samples with EO (21'39?) and without EO (21'17?). Beef samples were inoculated with L. monocytogenes at a concentration of 1 × 108 CFU/mL and vacuum-packed after EO addition at MIC value. Three heat treatments (F) were applied to reduce 1-log10 (F1), 2-log10 (F2) and 3-log10 (F3). EO composition was identified by gas-chromatography mass-spectrometry analysis. The main compounds identified were ß-pinene (11.70%), camphor (8.21%), ß-thujene (7.82%), 1.8-cineole (5.19%), a-humulene (6.07%) and endoborneol (4.87%).A reduction of approximately 1 log (CFU/g) of L. monocytogenes was observed in EO samples, compared to control samples at 2 °C. At 8 °C, despite exponential development from day 14, lower L. monocytogenes counts were observed in EO samples. Data showed that sage EO can help to control L. monocytogenes growth. However a possibility of using sage as a natural preservative, must be combined with other agents to control microbial growth more effectively. © 2020 Elsevier Ltd