Given that the chemical composition of seafood species reflects the conditions characterizing the... more Given that the chemical composition of seafood species reflects the conditions characterizing their geographic area of origin, this study aims to describe and compare the nutritional composition of several seafood species marketed in Luanda (Angola) and in Faro (Portugal), namely octopus (Octopus sp.), large-eye dentex (Dentex macrophthalmus), hake (Merluccius sp.) and barracuda (Sphyraena guachancho). In addition, a sensory-based methodology (the Quality Index Method, QIM) was carried out and a set of physicochemical parameters (pH, total volatile basic nitrogen (TVBN) and thiobarbituric acid reactive substances (TBARS)) were determined to assess the degree of freshness and quality of the different species. The results showed that location significantly (t-test, p < 0.05) influences some parameters of the nutritional composition, viz. moisture, protein content and lipid content. Quality indexes (QI) resulting from sensory analyses using QIM schemes were less than five (out of a maximum of 16–19 demerit points) indicating seafood’s high quality. In terms of physicochemical quality parameters, the values of pH varied between 6.11 for octopus and 6.78 for large-eye dentex, TVBN content ranged from 5.4 mg N/100 g for octopus and 9.6 mg N/100 g for barracuda in Luanda, and TBARS concentrations varied between 0.43 mg MDA/kg for large-eye dentex in Faro and 2.09 mg MDA/kg for hake in Faro. For every species studied the values were well below acceptable limits for consumption considering EU regulations (25–35 mg N/100 g for TVBN) and literature (7-8 µg MDA/g for TBARS), both in Luanda and in Faro. This study provides original results about nutritional composition and sensory and physicochemical indicators of seafood freshness and quality for the studied species in Luanda.
A methodology based on sensory analysis (Quality Index Method, or QIM) and a set of physicochemic... more A methodology based on sensory analysis (Quality Index Method, or QIM) and a set of physicochemical parameters (pH, total volatile basic nitrogen (TVB-N) content, peroxide value (PV), and the concentration of thiobarbituric acid reactive substances (TBARS)) was used to evaluate the degree of freshness/quality and estimate the shelf life of fresh and chilled mackerel and horse mackerel, marketed in Luanda (Angola) and in Faro (Portugal). Mackerel (n = 25) and horse mackerel (n = 27) were stored and chilled on ice at 5 ℃ during 11–13 days and sampled regularly. On day 7, the sensory panels in Faro and Luanda rejected both species. Moreover, TVB-N contents in mackerel (37.34 ± 2.61 mg N/100 g in Luanda and 37.57 ± 1.17 mg N/100 g in Faro) and horse mackerel (30.11 ± 3.45 mg N/100 g in Luanda and 49.12 ± 0.84 mg N/100 g in Faro), were above the values stipulated in EU regulation (25-35 mg N/100 g). In addition, concentration of TBARS (25.12 ± 7.76 µg MDA/g in Faro and 10.51 ± 1.01 µg MDA/g in Luanda for mackerel and 11.50 ± 2.18 µg MDA/g in Faro and 7.44 ± 2.80 µg MDA/g in Luanda for horse mackerel) were above the suggested limit of 7–8 µg MDA/g. Therefore, based on these results and the other quality parameters evaluated in this study, mackerel and horse mackerel marketed in Luanda and in Faro should be stored with ice at 5 ℃ to obtain a maximum shelf-life of up to 7 days.
Honey has long been used as a food and has been reported to have potential health benefits. In th... more Honey has long been used as a food and has been reported to have potential health benefits. In this work, total phenol content, colour and antioxidant and hepatoprotective activities of honey samples of different floral origins from the State of Hidalgo, Mexico were explored using in vitro assays. Hepatoprotective activity was measured by inhibitition of β-glucuronidase; gastroprotective activity was determined by inhibition of urease; antioxidant activity was evaluated by 2,2'-Azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and 2, 2-diphenyl-1-picrylhydrazyl (DPPH) methods. All the parameters showed significant differences (p<0.05) among honey samples. The total phenolic content ranged from 18.02 to 102.77 mg GAE 100 g-1. The colour ranged from extra light amber to dark amber. Inhibition of β-glucuronidase ranged from 23.70% to 36.00%, while urease inhibition ranged between 7.64% and 63.80%. The antioxidant activity by ABTS was between 44.68 and 441.56 mg AAE 100 g-1...
The effect of temperature on the phenol content, flavonoids content, hydroxymethylfurfural (HMF) ... more 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 APPLICATIONS Currently, 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.
Honey and some traditional honey products (mead and abbamele or agua-mel) are some attractive sou... more Honey and some traditional honey products (mead and abbamele or agua-mel) are some attractive sources of nutraceuticals and medical ingredients for healthy foods (Kucuk et al., Food Chemistry 100(2): 526–534, 2007). These products are rich in secondary metabolites as natural antioxidants (phenolic acids and flavonoids) and contribute to human health.
Visible and near-infrared reflectance spectroscopy (Vis/NIRS) was used to predict the ultimate pH... more Visible and near-infrared reflectance spectroscopy (Vis/NIRS) was used to predict the ultimate pH (pHu), color, intramuscular fat (IMF) and shear force (WBSF) of pork samples and to build classifiers capable of categorizing the samples by tenderness (tender or tough) and juiciness (juicy and dry). Spectra were collected from 400 to 1495 nm, and 200 data points were generated for every sample (n = 134). Sixty-seven percent of the sample set was used for calibration, and 33% was used for validation. Partial least squares (PLS) calibration models were developed for each characteristic measured. A coefficient of determination (R 2) and residual prediction deviation (RPD) were used to evaluate the accuracy of the calibration models. The pHu and color prediction models developed in this study fit this classification, indicating that these predictive models can be used to predict quality traits of intact pork samples. The Vis/NIRS offered great potential for correctly classifying pork Longissimus into two tenderness and two juiciness classes.
The aim of this study was to discriminate four commercial brands of Portuguese honeys according t... more 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.
Abstract: There is a growing concern on environmental impacts resulted from construction activiti... more Abstract: There is a growing concern on environmental impacts resulted from construction activities. Environmental assessment is a tool for reviewing, monitoring, checking and evaluating environmental performance for the construction industry, has been advocated. ...
In this study, the effects of thermal processing in the antibacterial activity of four multiflora... more 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. The consumer trend to search for minimally processed foods has increased in recent years due to the perception that food processing decreases its health benefits and antibacterial activities. Honey can inhibit pathogenic bacteria, but this inhibition is determined by the floral source from which the honey is collected. In this study, it was shown that thermal processing has a different effect on the antibacterial activities of each honey. These effects were linear or quadratic according to the bacteria (Bacillus subtilis, Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, Salmonella typhimurium and Pseudomonas aeruginosa) and the floral source of the honey. This effect did not depend on the Gram (the inhibition against Salmonella typhimurium was linear with respect to the thermal process in all honey), in contrast to E. coli (where the effect was quadratic with a peak at 60C in all of the honey). The results led to the conclusion that the thermal processing of each honey must be different to maximize their beneficial health effects as well as their antibacterial activities.
La presente revisión contribuye al conocimiento de tecnologías emergentes, como el ultrasonido e... more La presente revisión contribuye al conocimiento de tecnologías emergentes, como el ultrasonido en el tratamiento de la miel y su efecto sobre la cristalización, compuestos bioactivos e hidroximetilfurfural.
INTRODUÇÃO A Comunidade Europeia tem vindo a incentivar a cooperação entre instituições de ensino... more INTRODUÇÃO 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). O reconhecimento de estudos e diplomas é um pré-requisito para a criação de um espaço europeu de educação e formação em que estudantes e professores possam circular livremente. O Sistema Europeu de Transferência de Créditos (European Credit Transfer System-ECTS) foi desenvolvido pela Comissão das Comunidades Europeias num esquema piloto e...
Abstract: There is a growing concern on environmental impacts resulted from construction activiti... more Abstract: There is a growing concern on environmental impacts resulted from construction activities. Environmental assessment is a tool for reviewing, monitoring, checking and evaluating environmental performance for the construction industry, has been advocated. ...
The purpose of this work was to investigate the physicochemical changes occurring during the ther... more 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.
Twenty Churra-breed suckling lamb carcasses from two groups of animals were used in this study. O... more Twenty Churra-breed suckling lamb carcasses from two groups of animals were used in this study. One group had been reared on maternal milk (MM), and the other had been reared on milk replacer (MR) until slaughter at 25–35 days old. The effects of the type of milk on several meat quality traits were studied. These effects included pH, colour, WHC, texture, retinol and tocopherol concentrations, colour and lipid oxidation stability, and the volatile compounds that formed during boiling of the meat. Furthermore, a sensory analysis (triangle test) was carried out. The colour of M. longissimus dorsi of MM samples showed higher L*, lower a*, and higher b* values than those of MR samples (P<0.05). Retinol, α-, δ- and γ-tocopherol levels were all higher in the meat of lambs reared on MM (P<0.001). Rancimat tests and TBARS analysis revealed more lipid-oxidative stability for the meat of the MR group, and the colour of meat from this group was also more stable. Likewise, volatile compou...
Given that the chemical composition of seafood species reflects the conditions characterizing the... more Given that the chemical composition of seafood species reflects the conditions characterizing their geographic area of origin, this study aims to describe and compare the nutritional composition of several seafood species marketed in Luanda (Angola) and in Faro (Portugal), namely octopus (Octopus sp.), large-eye dentex (Dentex macrophthalmus), hake (Merluccius sp.) and barracuda (Sphyraena guachancho). In addition, a sensory-based methodology (the Quality Index Method, QIM) was carried out and a set of physicochemical parameters (pH, total volatile basic nitrogen (TVBN) and thiobarbituric acid reactive substances (TBARS)) were determined to assess the degree of freshness and quality of the different species. The results showed that location significantly (t-test, p < 0.05) influences some parameters of the nutritional composition, viz. moisture, protein content and lipid content. Quality indexes (QI) resulting from sensory analyses using QIM schemes were less than five (out of a maximum of 16–19 demerit points) indicating seafood’s high quality. In terms of physicochemical quality parameters, the values of pH varied between 6.11 for octopus and 6.78 for large-eye dentex, TVBN content ranged from 5.4 mg N/100 g for octopus and 9.6 mg N/100 g for barracuda in Luanda, and TBARS concentrations varied between 0.43 mg MDA/kg for large-eye dentex in Faro and 2.09 mg MDA/kg for hake in Faro. For every species studied the values were well below acceptable limits for consumption considering EU regulations (25–35 mg N/100 g for TVBN) and literature (7-8 µg MDA/g for TBARS), both in Luanda and in Faro. This study provides original results about nutritional composition and sensory and physicochemical indicators of seafood freshness and quality for the studied species in Luanda.
A methodology based on sensory analysis (Quality Index Method, or QIM) and a set of physicochemic... more A methodology based on sensory analysis (Quality Index Method, or QIM) and a set of physicochemical parameters (pH, total volatile basic nitrogen (TVB-N) content, peroxide value (PV), and the concentration of thiobarbituric acid reactive substances (TBARS)) was used to evaluate the degree of freshness/quality and estimate the shelf life of fresh and chilled mackerel and horse mackerel, marketed in Luanda (Angola) and in Faro (Portugal). Mackerel (n = 25) and horse mackerel (n = 27) were stored and chilled on ice at 5 ℃ during 11–13 days and sampled regularly. On day 7, the sensory panels in Faro and Luanda rejected both species. Moreover, TVB-N contents in mackerel (37.34 ± 2.61 mg N/100 g in Luanda and 37.57 ± 1.17 mg N/100 g in Faro) and horse mackerel (30.11 ± 3.45 mg N/100 g in Luanda and 49.12 ± 0.84 mg N/100 g in Faro), were above the values stipulated in EU regulation (25-35 mg N/100 g). In addition, concentration of TBARS (25.12 ± 7.76 µg MDA/g in Faro and 10.51 ± 1.01 µg MDA/g in Luanda for mackerel and 11.50 ± 2.18 µg MDA/g in Faro and 7.44 ± 2.80 µg MDA/g in Luanda for horse mackerel) were above the suggested limit of 7–8 µg MDA/g. Therefore, based on these results and the other quality parameters evaluated in this study, mackerel and horse mackerel marketed in Luanda and in Faro should be stored with ice at 5 ℃ to obtain a maximum shelf-life of up to 7 days.
Honey has long been used as a food and has been reported to have potential health benefits. In th... more Honey has long been used as a food and has been reported to have potential health benefits. In this work, total phenol content, colour and antioxidant and hepatoprotective activities of honey samples of different floral origins from the State of Hidalgo, Mexico were explored using in vitro assays. Hepatoprotective activity was measured by inhibitition of β-glucuronidase; gastroprotective activity was determined by inhibition of urease; antioxidant activity was evaluated by 2,2'-Azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and 2, 2-diphenyl-1-picrylhydrazyl (DPPH) methods. All the parameters showed significant differences (p<0.05) among honey samples. The total phenolic content ranged from 18.02 to 102.77 mg GAE 100 g-1. The colour ranged from extra light amber to dark amber. Inhibition of β-glucuronidase ranged from 23.70% to 36.00%, while urease inhibition ranged between 7.64% and 63.80%. The antioxidant activity by ABTS was between 44.68 and 441.56 mg AAE 100 g-1...
The effect of temperature on the phenol content, flavonoids content, hydroxymethylfurfural (HMF) ... more 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 APPLICATIONS Currently, 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.
Honey and some traditional honey products (mead and abbamele or agua-mel) are some attractive sou... more Honey and some traditional honey products (mead and abbamele or agua-mel) are some attractive sources of nutraceuticals and medical ingredients for healthy foods (Kucuk et al., Food Chemistry 100(2): 526–534, 2007). These products are rich in secondary metabolites as natural antioxidants (phenolic acids and flavonoids) and contribute to human health.
Visible and near-infrared reflectance spectroscopy (Vis/NIRS) was used to predict the ultimate pH... more Visible and near-infrared reflectance spectroscopy (Vis/NIRS) was used to predict the ultimate pH (pHu), color, intramuscular fat (IMF) and shear force (WBSF) of pork samples and to build classifiers capable of categorizing the samples by tenderness (tender or tough) and juiciness (juicy and dry). Spectra were collected from 400 to 1495 nm, and 200 data points were generated for every sample (n = 134). Sixty-seven percent of the sample set was used for calibration, and 33% was used for validation. Partial least squares (PLS) calibration models were developed for each characteristic measured. A coefficient of determination (R 2) and residual prediction deviation (RPD) were used to evaluate the accuracy of the calibration models. The pHu and color prediction models developed in this study fit this classification, indicating that these predictive models can be used to predict quality traits of intact pork samples. The Vis/NIRS offered great potential for correctly classifying pork Longissimus into two tenderness and two juiciness classes.
The aim of this study was to discriminate four commercial brands of Portuguese honeys according t... more 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.
Abstract: There is a growing concern on environmental impacts resulted from construction activiti... more Abstract: There is a growing concern on environmental impacts resulted from construction activities. Environmental assessment is a tool for reviewing, monitoring, checking and evaluating environmental performance for the construction industry, has been advocated. ...
In this study, the effects of thermal processing in the antibacterial activity of four multiflora... more 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. The consumer trend to search for minimally processed foods has increased in recent years due to the perception that food processing decreases its health benefits and antibacterial activities. Honey can inhibit pathogenic bacteria, but this inhibition is determined by the floral source from which the honey is collected. In this study, it was shown that thermal processing has a different effect on the antibacterial activities of each honey. These effects were linear or quadratic according to the bacteria (Bacillus subtilis, Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, Salmonella typhimurium and Pseudomonas aeruginosa) and the floral source of the honey. This effect did not depend on the Gram (the inhibition against Salmonella typhimurium was linear with respect to the thermal process in all honey), in contrast to E. coli (where the effect was quadratic with a peak at 60C in all of the honey). The results led to the conclusion that the thermal processing of each honey must be different to maximize their beneficial health effects as well as their antibacterial activities.
La presente revisión contribuye al conocimiento de tecnologías emergentes, como el ultrasonido e... more La presente revisión contribuye al conocimiento de tecnologías emergentes, como el ultrasonido en el tratamiento de la miel y su efecto sobre la cristalización, compuestos bioactivos e hidroximetilfurfural.
INTRODUÇÃO A Comunidade Europeia tem vindo a incentivar a cooperação entre instituições de ensino... more INTRODUÇÃO 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). O reconhecimento de estudos e diplomas é um pré-requisito para a criação de um espaço europeu de educação e formação em que estudantes e professores possam circular livremente. O Sistema Europeu de Transferência de Créditos (European Credit Transfer System-ECTS) foi desenvolvido pela Comissão das Comunidades Europeias num esquema piloto e...
Abstract: There is a growing concern on environmental impacts resulted from construction activiti... more Abstract: There is a growing concern on environmental impacts resulted from construction activities. Environmental assessment is a tool for reviewing, monitoring, checking and evaluating environmental performance for the construction industry, has been advocated. ...
The purpose of this work was to investigate the physicochemical changes occurring during the ther... more 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.
Twenty Churra-breed suckling lamb carcasses from two groups of animals were used in this study. O... more Twenty Churra-breed suckling lamb carcasses from two groups of animals were used in this study. One group had been reared on maternal milk (MM), and the other had been reared on milk replacer (MR) until slaughter at 25–35 days old. The effects of the type of milk on several meat quality traits were studied. These effects included pH, colour, WHC, texture, retinol and tocopherol concentrations, colour and lipid oxidation stability, and the volatile compounds that formed during boiling of the meat. Furthermore, a sensory analysis (triangle test) was carried out. The colour of M. longissimus dorsi of MM samples showed higher L*, lower a*, and higher b* values than those of MR samples (P<0.05). Retinol, α-, δ- and γ-tocopherol levels were all higher in the meat of lambs reared on MM (P<0.001). Rancimat tests and TBARS analysis revealed more lipid-oxidative stability for the meat of the MR group, and the colour of meat from this group was also more stable. Likewise, volatile compou...
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