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Oliveira Lopes Figueira, Ana Cristina

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  • Antioxidant activity and protective effect of bee bread (honey and pollen) in aluminum-induced anemia, elevation of inflammatory makers and hepato-renal toxicity
    Publication . Bakour, Meryem; Al-Waili, Noori S.; El Menyiy, Nawal; Imtara, Hamada; Figueira, A.C.; Al-Waili, Thia; Lyoussi, Badiaa
    Aluminum toxicity might be related to oxidative stress, and the antioxidant activity and protective effect of bee bread, which contains pollen, honey and bees' enzymes, on aluminum induced blood and hepato-renal toxicity was investigated in rats. Chemical analysis and antioxidant capacity of bee bread were conducted. The animal experiment in rats included; group 1: received distilled water (10 ml/kg b.wt), group 2: received aluminum chloride (662.2 mg/kg b.wt), group 3: received aluminum chloride (662.2 mg/kg b.wt) and ethanolic extract of the bee bread (500 mg/kg b.wt), and group 4: received aluminum chloride (662.2 mg/kg b.wt) and ethanolic extract of the bee bread (750 mg/kg b.wt). Doses were given once daily via a gavage. C-reactive protein, transaminases, urea, creatinine, creatinine clearance, sodium and potassium and urine sodium and potassium were determined on day 28 of the experiment. Bee bread contained protein, fat, fiber, ash, carbohydrate, phenol and flavonoids and it exhibited antioxidant activity. Aluminum caused a significant elevation of blood urea, transaminase, C-reactive protein and monocyte count and significantly decreased hemoglobin. These changes were significantly ameliorated by the use of bee bread. Bee bread has an antioxidant property, and exhibited a protective effect on aluminum induced blood and hepato-renal toxicity and elevation of inflammatory markers C-reactive protein, leukocyte and monocyte counts.
  • Changes in physical and chemical parameters of the traditional portuguese product água-mel during the production process
    Publication . Figueira, A.C.; Cavaco, Teresa
    Changes in physical and chemical parameters (viscosity, total soluble solids and Hunter color parameters L*, a*, b*, chroma and hue angle) of água-mel were investigated throughout processing. Kinetic parameters for color change of heatprocessed água-mel were monitored. A zero-order kinetic model was applied to changes in L* and b*, while a* and C* were described using a first-order kinetic model. The heating process changed all three color parameters (L*, a*, b*), causing a shift toward the darker colors. Parameters L* decreased, while a*, b*, C* and hue angle (°h) increased during heating. Regarding changes in total soluble solids and in apparent viscosity, both fitted first-order kinetics. A direct relationship was found between the changes in these two parameters. The increase in both total soluble solids and viscosity affected a*, b* and C*. In addition, a flow diagram for the Portuguese água-mel production process has been established.
  • Antioxidantes em frutos e vegetais
    Publication . Marcelino, Ana Margarida; Figueira, Ana Cristina Oliveira Lopes
    O oxigénio é um elemento necessário à sobrevivência da maioria dos seres vivos. Contudo, este pode revelar-se tóxico, provocando a oxidação e a destruição celular. Em consequência desta oxidação formam–se, a partir do oxigénio molecular (O2), grupos de átomos extremamente reactivos – os radicais livres. A oxidação, tanto dos tecidos animais como dos tecidos vegetais, pode ocorrer tanto como resultado do simples metabolismo celular aeróbio formando os designados radicais livres endógenos, como também pelas agressões externas ao organismo que levam à formação dos radicais livres exógenos (Plummer, 1989).
  • Potentiation of Bioactive Compounds and Antioxidant Activity in Artisanal Honeys Using Specific Heat Treatments
    Publication . Pimentel-Gonzalez, D. J.; Jimenez-Alvarado, R.; Hernandez-Fuentes, A. D.; Figueira, A.C.; Suarez-Vargas, A.; Campos-Montiel, R. G.
    The effect of temperature on the phenol content, flavonoids content, hydroxymethylfurfural (HMF) and antioxidant activity (DPPH and ABTS) in five artisanal honeys of different floral origins was investigated. The total phenol and total flavonoid content showed either linear or quadratic curves (P<0.05) for heat treatment according to the origin of the honey. For HMF, all of the honeys displayed linear behavior with the heat treatments. All of the honeys had linear responses to temperature (P<0.05) and antioxidant activity as measured by DPPH. The antioxidant activity measured as the ABTS showed either a linear or quadratic (P<0.05) curve response depending on the floral origin. The profile of the correlation coefficients between the bioactive compounds (phenols, flavonoids and HMF) and antioxidant activity (DPPH and ABTS) was different for each type of honey. It is possible to enhance the antioxidant activity of artisanal honeys with a specific heat treatment.Practical ApplicationsCurrently, nutraceuticals use honey for its antioxidant activity. It is important to preserve and improve these properties for the consumer during the processing of honey. In this study, it was found that each honey should be heat treated specifically because each honey has different bioactive compounds according to its floral origin. For some honeys, the thermal behavior of the bioactive compounds and the antioxidant activity was quadratic, with the greatest activity at 70C, whereas for other honeys, the behavior was linear, with the highest bioactive compounds and antioxidant activity at 80C. To enhance the bioactive compounds and antioxidant activity of artisanal honeys, each honey should be treated at a different temperature depending on their linear or quadratic behavior.
  • Evolution of physicochemical parameters during the thermal-based production of água-mel, a traditional Portuguese honey-related food product
    Publication . Cavaco, Teresa; Figueira, Ana Cristina; González-Domínguez, Raúl; Sayago, Ana; Fernández-Recamales, Ángeles
    The purpose of this work was to investigate the physicochemical changes occurring during the thermal-based production of água-mel, a traditional Portuguese honey-related food product. The refractive index, color parameters (hue angle, H°; chroma, C*), and the content of total reducing sugars, glucose, fructose, total brown pigments, and 5-hydroxymethylfurfural were monitored along the entire production process, and their evolution was kinetically modelled. Thermal processing caused a gradual decrease in sugars, which was accompanied by the formation of brown pigments and 5-hydroxymethylfurfural, increased concentration of soluble solids as evaluated through refractive index measurements, as well as the appearance of darker colors. In particular, a zero-order kinetic model could explain the changes in H° and reducing sugars, while the evolution of refractive index, brown pigments, 5-hydroxymethylfurfural, C*, fructose, and glucose were best fitted using a first-order kinetics model.
  • Bioactive compounds and antibacterial activities in crystallized honey liquefied with ultrasound
    Publication . Peláez-Acero, A.; Cobos-Velasco, J.E.; González-Lemus, U.; Espino-Manzano, S.O.; Aguirre-Álvarez, G.; González-Montiel, L.; Figueira, A.C.; Campos-Montiel, R.G.
    The effect of ultrasound on the crystal size, phenols, flavonoids, Maillard products and antibacterial activity of crystallized honeys was studied. Three multifloral honeys (M), one monofloral (MO) and one honeydew (HD) honey were used. Ultrasound was performed at 42 kHz for different times (0, 5, 10 and 15 min). The antibacterial activities were tested against Salmonella typhimurium, Bacillus subtilis, Pseudomonas aeruginosa, Listeria mono cytogenes, Staphylococcus aureus and Escherichia coli. In all honeys, the parameters analyzed had significant dif ferences ((P < 0.05)). After 15 min of ultrasound the HD had increments of 44 mg of gallic acid/100 g of honey in phenols, and some M showed increase in flavonoids (5.64 mg of quercitin /100 g of honey) and improvement in inhibition against Salmonella typhimurium was 13.1%. In some honeys the correlation between phenols or fla vonoids and antibacterial activity were significant ((P < 0.05)). No correlation was found between Maillard products and antibacterial activity. The ultrasound treatment effect on the crystal size, phenols, flavonoid, Maillard products, and antibacterial activity of crystallized honeys were different in each honey.
  • Bioactive compounds, antioxidant and antimicrobial activity of propolis extracts during In vitro digestion
    Publication . González-Montiel, Lucio; Figueira, A.C.; Medina-Pérez, Gabriela; Fernández-Luqueño, Fabián; Aguirre-Álvarez, Gabriel; Pérez-Soto, Elizabeth; Pérez-Ríos, Sergio; Campos-Montiel, Rafael G.
    The objective of this research was to determine the content of total phenols, total flavonoids, and the antioxidant and antimicrobial activity of the ethanolic extracts of propolis obtained by two methodologies during in vitro digestion. Ethanolic extracts of propolis were obtained by ultrasound and maceration and the yield and content of the bioactive compounds, as well as their antimicrobial and antioxidant activity, were evaluated. Yields higher than those reported in other investigations (71.6%) were obtained. The highest content of phenols and flavonoids in the ethanolic extracts was 34,406.6 mg GAE/100 g in propolis from San Pedro, obtained by maceration (SP M), and 19,523.2 mg QE/100 g in propolis from Teotitlán, obtained by ultrasound (TU), respectively, being higher than what is established in Mexican regulations. The antioxidant and antimicrobial activity of the extracts was not affected by the method of obtaining. At the end of the in vitro digestion there was an 80% loss of the phenolic content and a 90% loss of the flavonoid content. Therefore, antioxidant activity was affected. On the other hand, ultrasound improves the obtaining of bioactive compounds. In vitro digestion decreases the content of bioactive compounds; therefore, their functional properties are affected. Thus, it is important to consider technologies that allow extracts to be protected from in vitro digestion conditions.
  • EFFECT OF THERMAL PROCESSING ON ANTIBACTERIAL ACTIVITY OF MULTIFLORAL HONEYS
    Publication . Pimentel-Gonzalez, D. J.; Basilio-Cortes, U. A.; Hernandez-Fuentes, A. D.; Figueira, A.C.; Quintero-Lira, A.; Campos-Montiel, R. G.
    In this study, the effects of thermal processing in the antibacterial activity of four multifloral honeys were determined. The thermal treatments were carried out at 30, 40, 50, 60, 70 and 80C, and the following characteristics were determined: total phenols and antibacterial activity of three gram-positive bacteria (Bacillus subtilis, Staphylococcus aureus and Listeria monocytogenes) and three gram-negative bacteria (Escherichia coli, Salmonella typhimurium and Pseudomonas aeruginosa). The results showed that the behavior of total phenols in relation to temperature depended on the floral sources of honey. The honeys presented curves of either linear or quadratic responses of the antibacterial activity in relation to the thermal process, depending on the honey's floral sources and the kind of bacterium to inhibit. The results suggest that the honey's antibacterial activities and behavior with the temperature are different depending on the honey's floral sources and the kind of bacteria that they inhibit.
  • ECTS o euro dos créditos
    Publication . Figueira, Ana Cristina Oliveira Lopes
    A Comunidade Europeia tem vindo a incentivar a cooperação entre instituições de ensino superior como uma forma de melhoramento da qualidade do ensino, com os correspondentes benefícios para os estudantes e para estas instituições. A mobilidade de estudantes é um elemento predominante desta cooperação, a qual, dentro da Europa, é organizada em torno do programa Socrates/Erasmus (European Community Action System for the Mobility of University Students). O sucesso deste programa fez com que o mesmo fosse, a partir do ano académico de 1992/93, alargado á cooperação com qualquer país pertencente à Associação Europeia de Comércio Livre (EFTA).
  • Determination of the botanical origin of honey by sensor fusion of impedance e-tongue and optical spectroscopy
    Publication . Ulloa, P. A.; Guerra, Rui Manuel Farinha das Neves; Cavaco, A. M.; Costa, Ana M. Rosa da; Figueira, A.C.; Fernandes, A.
    The aim of this study was to discriminate four commercial brands of Portuguese honeys according to their botanical origin by sensor fusion of impedance electronic tongue (e-tongue) and optical spectroscopy (UV–Vis–NIR) assisted by Principal Component Analysis (PCA) and Cluster Analysis (CA). We have also introduced a new technique for variable selection through one-dimensional clustering which proved very useful for data fusion. The results were referenced against standard sample identification by classical melissopalynology analysis. Individual analysis of each technique showed that the e-tongue clearly outperformed the optical techniques. The electronic and optical spectra were fitted to analytical models and the model coefficients were used as new variables for PCA and CA. This approach has improved honey classification by the e-tongue but not by the optical methods. Data from the three techniques was then considered simultaneously. Simple concatenation of all matrices did not improve the classification results. Multi-way PCA (MPCA) proved to be a good option for data fusion yielding 100% classification success. Finally, a variable selection method based on one-dimensional clustering was used to define two new approaches to sensor fusion, and both yielded sample clusters even better defined than using MPCA. In this work we demonstrate for the first time the feasibility of sensor fusion of electronic and optical spectroscopy data and propose a new variable selection method that improved significantly the classification of the samples through multivariate statistical analysis.