ESAV - DIA - Documentos de congressos (comunicações, posters, actas)
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Browsing ESAV - DIA - Documentos de congressos (comunicações, posters, actas) by Author "Andrade, Sónia"
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- Determination of Some Chemical Properties of Uncommon FloursPublication . Andrade, Sónia; Oliveira, Solange; Guiné, Raquel; Correia, PaulaFlours of wheat, chestnut, acorn and lupin were evaluated in relation to phenolic compounds, antioxidant activity, and oxalate content.At the chemical level the results show some variability between samples by type of flour, and the sample of chestnut flour presented the higher value of oxalate (0.00348 mg/100g) when compared to the other samples in the study. Considering the content of phenolic compounds, the sample that stood out was the acorn flour, having a high value of 0.812 g AGE/100 g. All the samples presented intermediate content of antioxidant activity and the sample that showed a slightly higher value was the wheat flour with a value of 0.746 mM TRE/g sample.
- Determination of the content of coenzymes Q9 and Q10 in pork meat from different breedsPublication . Andrade, Sónia; Guiné, Raquel; Roseiro, LuísaMeat contains basic and essential nutrients to humans, and recently has been given a special attention to the presence of bioactive compounds. The objective of this work was the simultaneous determination of coenzymes Q9 and Q10 in pork meat, using HPLC. For this study were used 122 samples from different muscles and different breeds of pork meat. Besides, it was also evaluated the influence of animal breed and muscle type in the contents of CoQ9 and CoQ10. The results showed that the breed influenced significantly the mean content of CoQ9 (0.70 mg 100g-1) and CoQ10 (3.76 mg 100g-1) (P<0.0001), being this significantly higher in the meat from the breed Alentejano when compared to the other breeds (Large White and Landrace). The type of muscle was also responsible for the variation in the levels of coenzymes in the samples analysed (P<0.05) and (P<0.0001) respectively. From the results obtained it was concluded that the breed Alentejano presented the highest contents in both coenzymes (CoQ9 and CoQ10) and that, among the muscles evaluated, the muscle Semimembranousus (Sm) showed higher concentrations of CoQ10.
- Evaluation of some chemical properties of different flours.Publication . Andrade, Sónia; Oliveira, Solange; Guiné, Raquel; Correia, PaulaThe antinutritional factors in flours include phenol, tannin, oxalate, phytate and alkaloids. Wheat is one of the most important food for the world population, in which about 35% of the total world population regularly consume wheat-based foods.In recent times, there has been growing interest in using chestnut flour for use in bakery because its chemical composition is close to many cereals. The acorn is the fruit with an edible oval that grows on trees called by oaks, and contains in its composition a high starch content. There are available on the market a great variety of industrial products made from acorn flour or starch, including breads, cakes, soups, jelly, among others range. The lupine flour is of enormous importance, being widely used in the food industry to improve the nutritional value of other foods. In this work, five types of flours made were evaluated in relation to some chemical properties (oxalate, phenolic compounds and antioxidant activity). At the chemical level the results show some variability between samples by type of flour, and the sample of chestnut flour presented higher value of oxalate (3.48 g/100g) when compared to the other samples in the study. With respect to the content of phenolic compounds the sample that stood out was the acorn flour, having a value of 0.812 g EAG/100 g. Regarding the determination of antioxidant activity the sample that showed a slightly higher value than the other samples was the sample of wheat flour with a value of 0.746 mM TE/g sample.
- Modeling of Drying Kinetics of ChestnutsPublication . Correia, Paula; Andrade, Sónia; Guiné, RaquelChestnuts (Castanea Sativa) are produced in Portugal in considerable amounts, thus providing an important economic trade. Furthermore, apart from being eaten in their natural state, they can be used for a multiplicity of industrial applications, either in their natural form or after dehydration. In this work the drying kinetics of different cultivars of chestnuts was investigated, and the experiments were carried out under isothermal conditions, using a convective drier set to a temperature of 60 ºC. The experimental data obtained for the variations of moisture content along drying was fit to three thin layer models from literature with success. The experimental drying rate points were expressed as moisture ratio versus time. The results obtained allowed concluding that some chestnuts had higher initial moisture content than others and also that the presence or absence of the peel did not influence the initial moisture content of the chestnuts from the different cultivars tested. Regarding the drying curves observed for the cultivars tested, they show some differences. As to the mathematical modeling of the drying kinetics, the three models used show different performances, being the Vega-Lemus model slightly less adequate to fit the experimental sets of points.
- Modelling the Desorption Isotherms of ChestnutsPublication . Barroca, Maria João; Guiné, Raquel; Correia, Paula; Andrade, Sónia; Pina, AndreiaThe sorption isotherm of food material is pertinent in the processing and storage of food products. Desorption isotherms for peeled and unpeeled chestnuts were investigated using the hygrometric technique at 60 ºC and water activity (aw) ranged between 0.989 and 0.23. The experimental data were compared with four widely recommended models in the literature for food sorption isotherms (GAB, Freundlich, Henderson, and Smith). A non-linear least square regression program was used to evaluate the models constants. The four models were found to be acceptable for predicting the moisture sorption isotherms for chestnut cultivars. However, the empirical Smith model followed by the kinetic GAB was found to better represent the experimental data in the water activity range. Overall, the Smith model appears to be most suitable for fitting the desorption moisture isotherms data for the chestnut.
- Physical-chemical properties of Corema album (white crowberry or camarinha)Publication . Andrade, Sónia; Gonçalves, Fernando; Guiné, RaquelThis study evaluated the biometric characteristics (diameter, mass), the chemical properties (moisture content, fiber, total and reducing sugars, total soluble solids, total acidity), and some physical properties (color, texture). The results obtained showed that the Corema album berries had an average diameter of 8.63 ± 0.84 mm, and a mass of 0.66 ± 0.11 g. Regarding the chemical analysis, the results obtained show an average moisture content of 87.89 ± 4.01 % (fresh weight) and a fiber content of 36.52 ± 1.96 % (dry matter). The percentage of total and reducing sugars was 62.80 ± 0.77 % and 41.24 ± 1.74 % (dry matter), respectively. The result also showed Brixº of 6.20 ± 0.03 and a total acidity of 10.7 ± 0.1 % (Citric Acid). This study allowed concluding that the berries Corema album at study showed parameters of diameter and mass higher than those reported in the bibliography. It was also possible to conclude through the chemical analyzes performed that these berries are a very rich source of water, fibers and total sugars. Finally , these results confirm that Corema album berries have multiple physical-chemical properties that may be of high interest to the market of commercial berries.