Bran of different rice cultivars produced in Portugal were used to study supercritical carbon dio... more Bran of different rice cultivars produced in Portugal were used to study supercritical carbon dioxide extraction conditions of rice bran oil (RBO) and evaluate and compare antioxidant activity and fatty acid composition of the different rice bran varieties. The effect of plant loading (10–20 g), CO2 flow rate (0.5–1.5 L/min), pressure (20–60 MPa), and temperature (40–80 °C) was studied. The amount of oil extracted ranged from 11.72%, for Ariete cultivar, to 15.60%, for Sirio cultivar. The main fatty acids components obtained were palmitic (13.37%–16.32%), oleic (44.60%–52.56%), and linoleic (29.90%–38.51%). Excellent parameters of the susceptibility to oxidation of the oils were obtained and compare. RBO of Ariete and Gladio varieties presented superior DPPH and ABTS radical scavenging activities, whereas, Minima, Ellebi, and Sirio varieties had the lowest scavenging activities. Moreover, the oil obtained towards the final stages of extraction presented increased antioxidant activity.
Nos últimos anos, a extração sortiva em barra de agitação (SBSE) tornou-se numa técnica analítica... more Nos últimos anos, a extração sortiva em barra de agitação (SBSE) tornou-se numa técnica analítica bem estabelecida no domínio do preparo de amostras, tendo sido propostas na literatura centenas de aplicações em diversas áreas científicas. Esta notável ferramenta analítica evidencia grande capacidade para microextração estática e excepcional desempenho para operar ao nível vestigial dos sub-traços, em particular na análise de sistemas complexos. A presente contribuição tem por objetivo rever o estado da arte da SBSE, assim como propor o potencial analítico desta inovadora técnica, abordando os princípios fundamentais e fornecer know-how aos principiantes.
Salvia sclareoides is an aromatic herb native to Portugal, of which phenolic content (Folin-Cioca... more Salvia sclareoides is an aromatic herb native to Portugal, of which phenolic content (Folin-Ciocalteau method), chemical profile (HPLC/DAD), antioxidant activity (DPPH, b-carotene/linoleic acid assays), acute toxicity (MTT method, adapted for non-adherent cells), genotoxicity (short-term chromosomal aberration assay) and prion binding properties were evaluated in the acetone, water, ethanol, methanol and n-butanol extracts. The latter presented the highest phenolic content and antioxidant activity (DPPH assay), and was the single one with the flavonoids (+)-catechin, kaempferol O-glucoside and quercetin. Vanillic acid was the major component of all extracts but gallic, gentisic, caffeic, syringic, coumaric and ferulic acids were also found in some extracts. Only the n-butanol extract had components binding to the cellular form of human prion protein detected by NMR which showed specificity for two regions of the folded domain and for the unstructured N-terminal region. Extracts were not cytotoxic nor genotoxic, reinforcing the potential of S. sclareoides for nutraceutical purposes.
Multi-spheres adsorptive microextraction using powdered activated carbons (ACs) was studied as a ... more Multi-spheres adsorptive microextraction using powdered activated carbons (ACs) was studied as a novel enrichment approach, followed by liquid desorption and high-performance liquid chromatography with diode array detection (MSAµE(AC)-LD/HPLC-DAD) to monitor caffeine (CAF) and acetaminophen (ACF) traces in environmental matrices. In this study, commercial activated carbons (N, NOX, and R) were tested, with the latter showing a much better performance for the analysis of both anthropogenic drugs. The main parameters affecting the efficiency of the proposed methodology are fully discussed using commercial AC(R). Textural and surface chemistry properties of the ACs sample were correlated with the analytical results. Assays performed on 30 mL of water samples spiked at 10 µg L−1 under optimized experimental conditions, yielding recoveries of 75.3% for ACF and 82.6% for CAF. The methodology also showed excellent linear dynamic ranges for both drugs with determination coefficients higher ...
Green coffee bean isotopes have been used to trace the effects of different climatic and geologic... more Green coffee bean isotopes have been used to trace the effects of different climatic and geological characteristics associated with the Hawaii islands. Isotope ratio mass spectrometry (IRMS) and inductively coupled plasma mass spectrometry ((MC)-ICP-SFMS and ICP-QMS) were applied to determine the isotopic composition of carbon (δ 13 C), nitrogen (δ 15 N), sulfur (δ 34 S), and oxygen (δ 18 O), the isotope abundance of strontium (87 Sr/ 86 Sr), and the concentrations of 30 different elements in 47 green coffees. The coffees were produced in five Hawaii regions: Hawaii, Kauai, Maui, Molokai, and Oahu. Results indicate that coffee plant seed isotopes reflect interactions between the coffee plant and the local environment. Accordingly, the obtained analytical fingerprinting could be used to discriminate between the different Hawaii regions studied.
Bran of different rice cultivars produced in Portugal were used to study supercritical carbon dio... more Bran of different rice cultivars produced in Portugal were used to study supercritical carbon dioxide extraction conditions of rice bran oil (RBO) and evaluate and compare antioxidant activity and fatty acid composition of the different rice bran varieties. The effect of plant loading (10–20 g), CO2 flow rate (0.5–1.5 L/min), pressure (20–60 MPa), and temperature (40–80 °C) was studied. The amount of oil extracted ranged from 11.72%, for Ariete cultivar, to 15.60%, for Sirio cultivar. The main fatty acids components obtained were palmitic (13.37%–16.32%), oleic (44.60%–52.56%), and linoleic (29.90%–38.51%). Excellent parameters of the susceptibility to oxidation of the oils were obtained and compare. RBO of Ariete and Gladio varieties presented superior DPPH and ABTS radical scavenging activities, whereas, Minima, Ellebi, and Sirio varieties had the lowest scavenging activities. Moreover, the oil obtained towards the final stages of extraction presented increased antioxidant activity.
Nos últimos anos, a extração sortiva em barra de agitação (SBSE) tornou-se numa técnica analítica... more Nos últimos anos, a extração sortiva em barra de agitação (SBSE) tornou-se numa técnica analítica bem estabelecida no domínio do preparo de amostras, tendo sido propostas na literatura centenas de aplicações em diversas áreas científicas. Esta notável ferramenta analítica evidencia grande capacidade para microextração estática e excepcional desempenho para operar ao nível vestigial dos sub-traços, em particular na análise de sistemas complexos. A presente contribuição tem por objetivo rever o estado da arte da SBSE, assim como propor o potencial analítico desta inovadora técnica, abordando os princípios fundamentais e fornecer know-how aos principiantes.
Salvia sclareoides is an aromatic herb native to Portugal, of which phenolic content (Folin-Cioca... more Salvia sclareoides is an aromatic herb native to Portugal, of which phenolic content (Folin-Ciocalteau method), chemical profile (HPLC/DAD), antioxidant activity (DPPH, b-carotene/linoleic acid assays), acute toxicity (MTT method, adapted for non-adherent cells), genotoxicity (short-term chromosomal aberration assay) and prion binding properties were evaluated in the acetone, water, ethanol, methanol and n-butanol extracts. The latter presented the highest phenolic content and antioxidant activity (DPPH assay), and was the single one with the flavonoids (+)-catechin, kaempferol O-glucoside and quercetin. Vanillic acid was the major component of all extracts but gallic, gentisic, caffeic, syringic, coumaric and ferulic acids were also found in some extracts. Only the n-butanol extract had components binding to the cellular form of human prion protein detected by NMR which showed specificity for two regions of the folded domain and for the unstructured N-terminal region. Extracts were not cytotoxic nor genotoxic, reinforcing the potential of S. sclareoides for nutraceutical purposes.
Multi-spheres adsorptive microextraction using powdered activated carbons (ACs) was studied as a ... more Multi-spheres adsorptive microextraction using powdered activated carbons (ACs) was studied as a novel enrichment approach, followed by liquid desorption and high-performance liquid chromatography with diode array detection (MSAµE(AC)-LD/HPLC-DAD) to monitor caffeine (CAF) and acetaminophen (ACF) traces in environmental matrices. In this study, commercial activated carbons (N, NOX, and R) were tested, with the latter showing a much better performance for the analysis of both anthropogenic drugs. The main parameters affecting the efficiency of the proposed methodology are fully discussed using commercial AC(R). Textural and surface chemistry properties of the ACs sample were correlated with the analytical results. Assays performed on 30 mL of water samples spiked at 10 µg L−1 under optimized experimental conditions, yielding recoveries of 75.3% for ACF and 82.6% for CAF. The methodology also showed excellent linear dynamic ranges for both drugs with determination coefficients higher ...
Green coffee bean isotopes have been used to trace the effects of different climatic and geologic... more Green coffee bean isotopes have been used to trace the effects of different climatic and geological characteristics associated with the Hawaii islands. Isotope ratio mass spectrometry (IRMS) and inductively coupled plasma mass spectrometry ((MC)-ICP-SFMS and ICP-QMS) were applied to determine the isotopic composition of carbon (δ 13 C), nitrogen (δ 15 N), sulfur (δ 34 S), and oxygen (δ 18 O), the isotope abundance of strontium (87 Sr/ 86 Sr), and the concentrations of 30 different elements in 47 green coffees. The coffees were produced in five Hawaii regions: Hawaii, Kauai, Maui, Molokai, and Oahu. Results indicate that coffee plant seed isotopes reflect interactions between the coffee plant and the local environment. Accordingly, the obtained analytical fingerprinting could be used to discriminate between the different Hawaii regions studied.
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