Percorrer por autor "Abreu, M."
A mostrar 1 - 10 de 14
Resultados por página
Opções de ordenação
- Biochemical and colour changes of watercress (Nasturtium officinale R. Br.) during freezing and frozen storagePublication . Gonçalves, E.M.; Cruz, R.M.S.; Abreu, M.; Brandão, Teresa R. S.; Silva, Cristina L.M.The effects of water blanching, freezing, and frozen storage during 400 days at three different temperatures ( 7, 15 and 30 C), on watercress (Nasturtium officinale R. Br.) colour Hunter Lab parameters,chlorophyll degradation, vitamin C content loss and peroxidase (POD) activity were evaluated. The blanching induced significant changes on colour values and chlorophylls and vitamin C contents. POD activity was reduced 85% from its initial value. Freezing did not affect chlorophylls and vitamin C levels, however, promoted significant differences in colour values and POD residual activity. During frozen storage, ascorbic acid (AA) and POD activity Degradations followed first-order kinetics, and colour parameters (LH aH bH, aH/bH, LH aH/bH, LH/aH bH and hue (h0 H)) were successfully described by zero-order kinetics. The storage temperature effect was successfully described by the Arrhenius law. Chlorophylls and dehydroascorbic acid (DHAA) contents were kept constant during frozen storage.
- C-ERB-2, P53, Ki67 proteins and receptors of estrogen and progesterone on the prognosis of epithelial ovarian cancerPublication . Tomé, A.; Leal, I.; Palmeiras, C.; Matos, E.; Amado, J.; Abreu, M.; Lopes, C.Ovarian cancer is the seventh most common cancer diagnosed in women worldwide. To date, many studies in epithelial ovarian cancer (EOC) have reported on the association HER-2/neu, p53 proteins and steroid hormones and their respective receptors with prognosis and/or the carcinogenesis process, but no definitive conclusion has been reached. Objectives: To assess the proteins c-erbB-2, p53, Ki67 and receptors of estrogen (ER) and progesterone (PR) of EOC, with regard to clinical stage findings and its effect on survival. Methods: 125 patients with a diagnosis of EOC treated by primary surgery and chemotherapy have participated. A surgical stage was noted and analyzed the correlation with c-erbB-2, p53, Ki67, ER and PR. Immunohistochemical analysis, using the anti-c-erbB-2, p53, Ki67 monoclonal antibodies, the antibody cod PR clone PgR and code ER-6-F11 Anti human estrogen. The c-erbB-2 study was complemented by genetic amplification and was reported univariate and multivariate analysis. Results: Age 55.7 ± 16; 50.2% with residual disease (< 2 cm); initial (54.6%) and advanced (45.4%) stage. Univariate analysis showed positive staining for c-erbB-2, p-53, Ki67, PR and ER. The patients with negative receptors had a significantly shortened survival time (p = 0.01) than patients with positive receptors. Multivariable analysis revealed only clinical FIGO stage as an independent prognostic of overall survival (p = 0.002). Other variables like c-erbB-2, p53, Ki67, and ER were not significantly related to survival. Conclusions: We concluded that patients with negative PR had a significantly shortened survival time than patients with positive receptors. The overexpression of markers c-erbB-2, p53, Ki67, and ER, were not significantly related to survival in EOC. Only the FIGO stage was achieved to be an independent predictor of overall survival. They should be evaluated together with the patient’s clinical status and other prognostic factors.
- Carrot (Daucus carota L.) peroxidase inactivation, phenolic content and physical changes kinetics due to blanchingPublication . Gonçalves, E.M.; Pinheiro, J.; Abreu, M.; Brandão, T.R.S.; Silva, C.L.M.The kinetics of peroxidase thermal inactivation, total phenolic content degradation, and colour (CIE L*a*b*) and texture changes were studied in a temperature range of 70–90 C for carrots (Daucus carota L.). Peroxidase inactivation, total phenolic content degradation and the lightness colour (L* parameter) change were successfully described by a first-order reaction model. The redness and yellowness colour (a* and b* parameters, respectively) and texture (firmness and energy parameters) changes presented a fractional conversion kinetic model behavior. The temperature effect was well described by the Arrhenius law. All the blanching conditions recommended to reduce peroxidase inactivation to an acceptable level (90% loss of its original activity) ensured good quality retention. However, to obtain a high quality carrot product a balance must be made between colour and total phenolic content losses. Therefore, blanching at 80 C for 6 min is suggested as a compromise condition to maximize quality. The overall study indicated that colour is a critical parameter to optimize carrot hot water blanching condition.
- Differential scanning calorimetry as a tool for optimizing vegetables freezing and storage conditionsPublication . Gonçalves, E. M.; Lopes, C.; Pinheiro, J.; Lourenço, J. A. A.; Abreu, M.; Brandão, Teresa R. S.; Silva, C. L. M.
- Efeito dos tratamentos térmicos brandos na cor e textura da pêra “Rocha” minimamente processadaPublication . Abreu, M.; Gonçalves, E. M.; Vieira, J.; Silva, C. L. M.
- Evaluation of quality changes during frozen storage of watercress (Nasturtium officinale R. Br.)Publication . Teixeira, I.; Gonçalves, E. M.; Abreu, M.; Brandão, T. R. S.; Silva, C. L.M.
- Influence of blanching treatments on colour, texture, chlorophylls content and sensory quality of broccoli (Brassica oleracea L.)Publication . Gonçalves, E. M.; Pinheiro, J.; Abreu, M.; Brandão, Teresa R. S.; Silva, C. L. M.
- Kinetics of quality changes of pumpkin (Curcurbita maxima L.) stored under isothermal and non-isothermal frozen conditionsPublication . Gonçalves, E.M.; Pinheiro, J.; Abreu, M.; Brandão, Teresa R. S.; Silva, C. L. M.The effects of freezing process and frozen storage at isothermal (−7, −15 and −25 °C) and non-isothermal (accelerated life testing with step-stress methodology; temperature range from −30 to −5 °C) conditions on pumpkin quality were investigated. Storage temperature conditions were selected to embrace the limits practiced in the cold chain. Quality changes, such as texture, colour CIE Lab and vitamin C (ascorbic acid) content, were evaluated for both frozen storage regimes. The freezing process (that included a pre-blanching step) and subsequent frozen storage had significant impacts on all quality parameters analysed. A fractional conversion kinetic model was adequate in colour, texture and vitamin C data fits. The storage temperature effect was successfully described by the Arrhenius law. This study shows that non-isothermal frozen storage has a marked effect on pumpkin quality.
- Modelling the kinetics of peroxidase inactivation, colour and texture changes of pumpkin (Cucurbita maxima L.) during blanchingPublication . Gonçalves, E. M.; Pinheiro, J.; Abreu, M.; Brandão, Teresa R. S.; Silva, Cristina L.M.The effects of blanching treatment on peroxidase inactivation, colour and texture of pumpkin (Cucurbita maxima L.) were studied in the temperature range of 75–95 C. Peroxidase inactivation followed a first-order Arrhenius model, where the activation energy and rate of the reaction at a reference temperature of 85 C were 86.20 ± 5.57 kJ mol 1 and 0.27 ± 0.01 min 1, respectively. During blanching, pumpkin became darker and softer with processing time. The degradation of colour (evaluated throughout CIE L*a*b* colour system, with chroma index and total colour difference) and texture parameters (firmness and energy) showed a fractional conversion model kinetics, being the temperature effect on kinetic parameters well described by the Arrhenius law. The results of this work are a good tool to further optimise pumpkin blanching conditions.
- Novas tecnologias de pré-tratamento de hortofrutícolasPublication . Gonçalves, E. M.; Abreu, M.; Oliveira, A. J.; Portela, M.; Vieira, M. M. C.; Brandão, Teresa R. S.; Silva, C. L. M.