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...
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.
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. ...
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...
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.
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. ...
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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