Publications by authors named "Jose A Figueira"

Uveira-da-serra (Vaccinium padifolium Sm) is a native blueberry from Madeira Island (Portugal). In this study, the free low-molecular weight phenolic composition of Vaccinium padifolium berries (uva-da-serra - UdS), was established using a modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) strategy combined with liquid chromatography electrospray ionization tandem mass spectroscopy (LC-ESI-MSMS). Total phenolic content (TPC), total flavonoid content (TFC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS) radical-scavenging activities and oxygen radical absorbance capacity (ORAC) were also evaluated.

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In this study, the health-promoting benefits of different fruits grown in Madeira Island, namely lemon ( var. ), tangerine ( var. ), pitanga ( var.

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Tangerines () are popular fruits worldwide, being rich in many bioactive metabolites. The variety cultivated on Madeira Island has an intense aroma easily distinguishable from other tangerines, being traditionally used to enrich several foods and beverages. Nonetheless, volatile composition has never been characterized, and we aimed to unveil the bioactive potential of peels and juices of tangerines and compare them with the variety grown in Portugal mainland.

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Volatile fingerprints of a lager beer were carried out throughout five brewing steps to characterize the changes encompassing this process. Overall, 60 volatile organic metabolites (VOMs) were identified by headspace solid-phase microextraction followed by gas chromatography mass spectrometry (HS-SPME/GC-MS). Specific profiles were observed at different brewing steps - aldehydes and furans dominate in wort, whereas the aliphatic esters and alcohols predominate in the following steps.

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MEPS, the acronym of microextraction by packed sorbent, is a simple, fast and user- and environmentally-friendly miniaturization of the popular solid-phase extraction technique (SPE). In fact, it has been widely shown that MEPS can easily replace SPE for most, if not all, previous applications. It can attain this with obvious gains in sample and solvent usage, which is greatly reduced without compromising the extraction efficiency.

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The effect of ripening on the evolution of the volatomic pattern from endemic Vaccinium padifolium L. (Uveira) berries was investigated using headspace-solid phase microextraction (HS-SPME) followed by gas chromatography/quadrupole-mass spectrometry (GC-qMS) and multivariate statistical analysis (MVA). The most significant HS-SPME parameters, namely fibre polymer, ionic strength and extraction time, were optimized in order to improve extraction efficiency.

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The objective of this study was to evaluate the efficiency of a promising solid phase microextraction technique, μSPEed, in the analysis of selected phenolic compounds from teas by ultrahigh performance liquid chromatography with photodiode array detection (μSPEed/UHPLC-PDA). The innovative μSPEed configuration uses 3-μm sorbent particles tightly packed in a disposable needle equipped with a pressure-driven valve to withdraw samples in a single direction. The system was operated by the electronic pipette eVol® and different parameters influencing the extraction efficiency, as the nature of sorbent, pH, loading and elution conditions, and solvents were optimized.

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The volatile metabolomic patterns from different raw materials commonly used in beer production, namely barley, corn and hop-derived products - such as hop pellets, hop essential oil from Saaz variety and tetra-hydro isomerized hop extract (tetra hop), were established using a suitable analytical procedure based on dynamic headspace solid-phase microextraction (HS-SPME) followed by thermal desorption gas chromatography-quadrupole mass spectrometry detection (GC-qMS). Some SPME extraction parameters were optimized. The best results, in terms of maximum signal recorded and number of isolated metabolites, were obtained with a 50/30 μm DVB/CAR/PDMS coating fiber at 40 °C for 30 min.

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In this work a highly selective and sensitive analytical procedure based on semi-automatic microextraction by packed sorbents (MEPS) technique, using a new digitally controlled syringe (eVol(®)) combined with ultra-high pressure liquid chromatography (UHPLC), is proposed to determine the prenylated chalcone derived from the hop (Humulus lupulus L.), xanthohumol (XN), and its isomeric flavonone isoxanthohumol (IXN) in beers. Extraction and UHPLC parameters were accurately optimized to achieve the highest recoveries and to enhance the analytical characteristics of the method.

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