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Contém: Pathways in human cancer. Poster

Tese apresentada a concurso para especialista do Laboratório Nacional de Engenharia Civil, 1969

No presente trabalho são determinados os biofenóis em azeites ‘Galega’ e ‘Azeiteira’ obtidos em duas épocas de colheita dos frutos e olivais em produção integrada. A separação da fracção fenólica foi feita por extracção líquido-líquido (ELL) e a análise dos compostos fenólicos obtida por cromatografia líquida de alta pressão (HPLC) com detecção por díodos (DAD). São também determinados: os tocoferóis por HPLC e fluorescência (FLD); os biofenóis totais por espectroscopia VIS; e a intensidade do sabor amargo (K225) por espectroscopia UV. Os azeites ‘Galega’ e ‘Azeiteira’ apresentam teores mais elevados de antioxidantes na colheita mais temporã indicando que – do ponto de vista nutricional, sensorial e da estabilidade deste alimento – não é benéfico retardar a época de colheita. O hidroxitirosol e a luteolina decrescem acentuadamente na segunda data de colheita para os azeites de cultivar ‘Azeiteira’. Os azeites ‘Galega’ apresentam teores mais elevados de α-tocoferol e ϒ-tocoferol.

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Dehydration of peach is an alternative to enhance storage stability, mínimize packaging requirement and reducing post-harvest cost without a sensorial and nutritional quality loss. Preservation of fruits through sun drying techniques is practiced in Cova da Beira (a Portuguese region that has a protected geographical indication for peach), as a homemade process without quality and safety control. The aim of this work was to prepare quality dehydrated products based on a convective drying process with low cost. This process has short drying time and controlled temperature that causes minimal damage to the product without added preservatives or sugar. The samples of ‘Baby Gold’ cultivar (Prunus persica) obtained from local producer were peeled, laminated and immediately dehydrated. Samples were stored in sealed plastic containers at 25°C for subsequent analysis. In the drying process were controlled forced convection air velocity of 1.25 to 1.50 m/s, air temperature between 45 and 75°C and drying time between 7 to 11 hours. During dehydration process temperature and fruit moisture were controlled. pH, acidity, soluble solids content (SSC) and mesophilic aerobic count were performed in fresh and dehydrated fruit. Dehydrated peach were similar to homemade products. Moisture was below 12%, without significant variation of SSC and acidity (on a dry basis). No deleterious effect occurred on peach mesophilic aerobic count, since a slight decrease was registered between fresh and dehydrated fruit.

The development of sensors to measure fruit internal quality variables is one of the challenges of post-harvest technology. Visible-near infrared spectroscopy (Vis/NIRS) has been a promise technique for nondestructive fruit quality assessment. This study was focused to evaluate the use of Vis/NIRS in measuring the quality parameters of intact mandarin orange fruit (Citrus clementina). The parameters studied were: firmness, color (CIEL*a*b*), peel thickness, soluble solids content (SSC), pH and total acidity (TA). A total of 120 mandarin fruit with different maturation were sampled. Reflectance NIR spectra were collected in four points of each fruit and the fruits were posteriorly analyzed for the physico-chemical parameters. Prediction models were selected based on the highest r2, lowest standard error of calibration (RMSEC) and lower number of factors used in the calculation. For color parameters (L*, a*, and b*) model had a mean square error of calibration (RMSEC) of 0.877, 1.780 and 1.589 and coefficient determination (r2) of 0.923, 0.963 and 0.852, respectively. The proposed model for the SSC had a RMSEC of 0.314 and r2 of 0.749. The results indicate that Vis/NIRS technique could provide an accurate, reliable and nondestructive method for assessing the internal quality indices.

The cherry fruit is considered a nutrient dense food with a relatively low caloric content and a significant amount of important nutrients and bioactive food components. Nowadays there are some investigations regarding on nutritional and antioxidant properties of cherries. The objective of this study was to determine the stages of maturation of Sweetheart cherry from Cova da Beira (Portugal). Physicochemical parameters: firmness, color (L*, a* and b*), soluble solids content (SSC), pH, titratable acidity (TA), total phenolic content (Folin-Ciocalteu reagent method) and antioxidant activity (DPPH method) of ‘Sweetheart’ cherry were evaluated. Three maturation stages were identified and results demonstrated that solid soluble content, phenolic compounds and antioxidant activity increase with ripening stages. For soluble solids content and total phenolic content cherries showed the following average values: 19.9, 20.5 and 22.0 º Brix and 591, 788 and 810 mg galic acid kg-1, respectively. We can consider that this cultivar has an interest in nutritional terms, which may contribute to the enhancement of 'Sweetheart' cherry from the Cova da Beira region. Additionally, these data provide complementary information which can be used to ensure the quality of this regional product, ‘Cereja da Cova da Beira’.