23 documents found, page 1 of 3
Electronic nose coupled with linear and nonlinear supervised learning methods f...
Hidayat, S. N.; Rusman, A.; Julian, T.; Triyana, K.; Veloso, Ana C. A.; Peres, A. M.An electronic nose (E-nose), comprising eight metal oxide semiconductor (MOS) gas sensors and a moisture-temperature sensor, was used for classifying three quality grades of superior java cocoa beans, namely fine cocoa dark bean < 20%, fine cocoa dark bean > 60%, and bulk cocoa bean that is a harder task compared to the discrimination of high versus low-quality cocoa beans. The E-nose signals were pre-processed...
Electrochemical aptasensor array for multiple detection of human osteopontin
Meirinho, S.; Dias, L. G.; Peres, A. M.; Rodrigues, L. R.Electrochemical aptasensor arrays have been recently used to detect several proteins reported as disease biomarkers, mainly due to their known advantages, that include high affinity, sensitivity, specificity and low costs, among others. This study describes the development of a label-free electrochemical multi-aptasensor array, for the simultaneous detection of human osteopontin (OPN), using two specific aptame...
Electronic tongues and aptasensors
Dias, L. G.; Meirinho, S. G.; Veloso, Ana C. A.; Rodrigues, L. R.; Peres, A. M.The development of bioinspired sensors has emerged and grown in recent decades, given their broad and exciting applications to pharmaceutical formulations, medical diagnosis and health care. These sensor-based technologies, owing to their function and to the elements involved in their design, potentially generate fast, selective, sensitive, safe and green analysis solutions. Their applications have evolved into...
Dietary sugars analysis: quantification of fructooligossacharides during fermen...
Correia, Daniela Matilde Marques; Dias, Luís G.; Veloso, Ana C. A.; Dias, T.; Rocha, I.; Rodrigues, L. R.; Peres, A. M.In this work, a simple chromatographic method is proposed and in-house validated for the quantification of total and individual fructooligossacharides (e.g., 1-kestose, nystose, and 1F-fructofuranosylnystose). It was shown that a high-performance liquid chromatography with refractive index detector could be used to monitor the dynamic of fructooligossacharides production via sucrose fermentation using Aspergill...
Evaluation of healthy and sensory indexes of sweetened beverages using an elect...
Dias, Luís G.; Sequeira, Cédric; Veloso, Ana C. A.; Sousa, Mara E. B. C.; Peres, A. M.Overconsumption of sugar-sweetened beverages may increase the risk of health problems and so, the evaluation of their glycemic load and fructose-intolerance level is essential since it may allow establishing possible relations between physiologic effects of sugar-rich beverages and health. In this work, an electronic tongue was used to accurately classify beverages according to glycemic load (low, medium or hig...
Cyclic voltammetry : a tool to quantify 2,4,6-trichloroanisole in aqueous sampl...
Peres, A. M.; Freitas, P.; Dias, Luís G.; Sousa, Mara E. B. C.; Castro, L. M.; Veloso, Ana C. A.Chloroanisoles, namely 2,4,6-trichloroanisole, are pointed out as the primary responsible of the development of musty off-flavours in bottled wine, due to their migration from cork stoppers, which results in huge economical losses for wine industry. A prevention step is the detection of these compounds in cork planks before stoppers are produced. Mass spectrometry gas chromatography is the reference method used...
UV spectrophotometry method for dietary sugars
Veloso, Ana C. A.; Rodrigues, L. R.; Dias, Luís G.; Peres, A. M.This chapter is geared towards users of UV-Vis spectroscopic absorbance measurements. It will mainly focus on determination of the dietary sugars concentration in samples using raw or derivative absorbance spectra, by applying single or multivariate chemometric models. The most recent developments regarding the application of direct or indirect UVVis based methods for evaluating sugar contents are presented. Fu...
Equilibrium studies for the adsorption of fructo-oligosaccharides on a Dowex Mo...
Nobre, Clarisse; Vanková, K.; Peres, A. M.; Polakovic, M.; Teixeira, J. A.; Rodrigues, L. R.Fructo-oligosaccharides (FOS), namely kestose, nystose and fructo-furanosylnystose, are prebiotic sugars that can be obtained from sucrose by fermentation. The resulting fermentative broth is a complex mixture containing also salts and other smaller sugars that must be removed. In this study, a Dowex Monosphere calcium resin was evaluated for the separation of sugars. The adsorption behavior of FOS contained in...
Determination of 2,4,6-trichloroanisole by cyclic voltammetry
Freitas, P.; Dias, Luís G.; Peres, A. M.; Castro, L. M.; Veloso, Ana C. A.The electrochemical reduction of 2,4,6-trichloroanisole (TCA), a chlorinated arene with electron-donating substituents, was evaluated by cyclic voltammetry (CV). TCA is a major concern for the winery industry since it is related with “cork taint”, a wine defect. The results obtained showed that CV could be used to detect and quantify TCA in standard solutions. Linear relationships could be set between the curre...
New improved method for fructooligosaccharides production by Aureobasidium pull...
Dominguez, Ana; Nobre, Clarisse; Rodrigues, L. R.; Peres, A. M.; Torres, D.; Rocha, I.; Lima, Nelson; Teixeira, J. A.Fructooligosaccharides are prebiotics with numerous health benefits within which the improvement of gut microbiota balance can be highlighted, playing a key role in individual health. In this study, an integrated one-stage method for FOS production via sucrose fermentation by Aureobasidium pullulans was developed and optimized using experimental design tools. Optimization of temperature and agitation speed for ...