Browsing by Author "Pereira, P."
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- Cactus pear pulp as a source of bioactive compoundsPublication . Silva, M.A.; Albuquerque, T.G.; Pereira, P.; Ramalho, R.; Costa, H.S.Introduction: Cactus pear, also known as prickly pear or nopal cactus, is a specie from Cactaceae family, widely cultivated in semi-arid regions around the World. Cactus pear fruit has gained increasing importance due to its various applications ranging from nutrition to the pharmaceutical industry. In Portugal, in the last years, there was an increase in the cultivation of this plant, due to the growing interest of Portuguese producers. Aim: The aim of this study was to determine the antioxidant activity, the total phenolic compounds content and the total flavonoids content of the cactus pear pulp. Materials and Methods: In 2017, several samples of cactus pear were collected in Alentejo region (Portugal). Antioxidant activity of cactus pear was determined using two different methods (2,2-diphenyl-1-picryl-hydrazyl (DPPH•) and ferric reduction power (FRAP)). Moreover, total phenolic and total flavonoids contents were also assessed by spectrophotometric methodologies. The total phenolic compounds results were expressed as gallic acid equivalents (GAE), while the total flavonoid content was expressed as epicatechin equivalents (ECE). Results: The total phenolics content for the analysed cactus pear pulp was 19.8 ± 0.78 mg GAE/g, while the total flavonoid content was 1.70 ± 0.08 mg ECE/g. Regarding the antioxidant activity evaluation, the results obtained for the two analytical methods were 17.1 ± 0.71 mg/mL (EC50) and 46.6 ± 1.99 mg Trolox equivalents/g for DPPH• and FRAP assays, respectively. Conclusions: Based on the results obtained for the analysed cactus pear pulp, it is possible to conclude that it is a good source of bioactive compounds and can contribute to the intake of natural antioxidants. It is a fruit with nutritional interest and its use in human diet can bring benefits to the health of consumers.
- Chapter 44 - Prickly pearPublication . Albuquerque, T.G.; Pereira, P.; Silva, M.A.; Vicente, F.; Ramalho, R.; Costa, H.S.Nowadays, consumers are increasingly interested in foods that are linked with health benefits, in addition to their nutritional composition. Prickly pear (Opuntia ficus-indica (L.) Mill.) is native to Mexico, but nowadays it is widely spread among other regions of the world, such as Africa, Australia, and the Mediterranean basin, due to its pleasant organoleptic features. Prickly pear belongs to the Cactaceae family, which includes over 1500 species of cacti. Moreover, it is gaining popularity among consumers due to the presence of bioactive compounds, namely polyphenols, vitamins, polyunsaturated fatty acids, carotenoids, and sterols that are associated with relevant functional and biological activities, such as antiinflammatory, antioxidant, and hypoglycemic properties, among others. In addition, this plant can also be used as a fence in gardens and fields and is useful in helping to combat desertification as it grows in arid and semiarid regions. Nowadays, it is widely used to manufacture food products, such as juices and jams, but it is also consumed as a fruit. Prickly pear is a promising source of phytochemicals, which can be useful for food, or in the cosmetics or pharmaceutical industries to develop new products with health-promoting properties, namely, functional foods, natural additives, or dietary supplements.
- Comparative analysis of the nutritional composition of pulp and peel of prickly pearPublication . Silva, M.A.; Albuquerque, T.G.; Pereira, P.; Ramalho, R.; Costa, H.S.Introduction: Nowadays, there are two major concerns of society, namely: (i) concern for health and demand for foods that may have health benefits; and (ii) increase of food waste produced by the food industry. The study of food and its by-products features can be one of the solutions for these two major concerns. Aim: In this study a comparative analysis was performed between the pulp and the by-product of prickly pear determining moisture, ash, total protein, total fat and dietary fibre contents. Methods: In 2017, the prickly pears were obtained at Herdade de Peliteiros (Silveiras, Montemor-o-Novo, Évora). For determination of moisture content, a gravimetric method was used applying a dry air oven, and the ash content was determined using the process of incineration at 525 °C. For total protein content, Kjeldahl method was applied, and for total fat, acid hydrolysis followed by extraction with petroleum ether using a Soxhlet apparatus. Finally, the dietary fibre content was determined by an enzymatic-gravimetric method. Results: With the results obtained, it was possible to verify that water is the main constituent of the pulp and peel of prickly pear, 83% and 84%, respectively. It was also found that the pulp had a higher content of total protein, total fat and dietary fibre than the by-product of prickly pear. However, the peel also shows considerable amounts of dietary fibre (2,8 g/100 g). Conclusions: In summary, both parts of prickly pear can be considered a good source of dietary fibre. This study may also contribute to promote the use of prickly pear by-product in the formulation of new food products and therefore to reduce food waste.
- Effects of tryptamine on growth, ultrastructure, and oxidative stress of cyanobacteria and microalgae culturesPublication . Churro, C.; Fernandes, A. S.; Alverca, E.; Sam-Bento, F.; Paulino, S.; Figueira, V. C.; Bento, A. J.; Prabhakar, S.; Lobo, A. M.; Martins, L. L.; Mourato, M. P.; Pereira, P.Tryptamine was screened for selective antialgal activity against different cyanobacteria and eukaryotic microalgae. In a rapid 96-well microplate bioassay cultures were exposed to tryptamine concentrations from 0.625 to 20 lg ml-1 and growth was estimated by daily optical measurements over a 216 h period. Inhibitory concentrations (IC50216h) obtained from the sigmoidal inhibition curves showed that tryptamine prevents the growth of most cyanobacteria and eukaryotic microalgae at similar concentrations. However, most of the eukaryotic algae recovered growth after being transferred to new tryptamine-free culture media, while most cyanobacteria showed no growth recovery. Microscopical examination of exposed cells showed no major effects of tryptamine on eukaryotic ultrastructure but showed major-induced alterations on cyanobacteria (disorganization of thylakoid membranes, intratylakoidal vacuolization, increased cytoplasmatic granules, and cell lysis). Biochemical analyses performed on Aphanizomenon gracile (cyanobacteria) and Ankistrodesmus falcatus (chlorophyceae) showed that tryptamine induces an increase in H2O2 production in both cultures. Although no significant changes in catalase activity were detected, both cultures showed an increase in ascorbate peroxidase activity following tryptamine exposure treatments. Interestingly, lipid peroxidation was found to increase only in A. gracile, suggesting that the cellular defence mechanisms triggered by this cyanobacterium were less efficient than the ones triggered by A. falcatus for the removal of reactive oxygen species (ROS). Strong lipid peroxidation in cyanobacteria might lead to irreversible membrane damages which probably prevent these organisms to recover growth after tryptamine exposure. On the contrary, the eukaryotic alga seems to respond quite effectively to tryptamine induced oxidative stress and this would explain the capacity for this organism to recover growth after being exposed to tryptamine.
- Microcystin-LR activates the ERK1/2 kinases and stimulates the proliferation of the monkey kidney-derived cell line Vero-E6Publication . Dias, E.; Matos, P.; Pereira, P.; Batoréu, M.C.C.; Silva, M.J.; Jordan, P.Microcystin-LR (MCLR) is a peptide produced by freshwater cyanobacteria that induces severe hepatotoxicity in humans and animals. MCLR is also a potent tumour promoter and it has been proposed that this activity is mediated by the inhibition of protein phosphatases PP1/PP2A, possibly through the activation of proto-oncogenes c-jun, c-fos and c-myc. However, the mechanisms underlying MCLR-induced tumour promotion are still largely unknown, particularly in non-liver cells. In previous studies we have demonstrated that micromolar concentrations of MCLR induce cytotoxic effects in the kidney Vero-E6 cell line. The purpose of the present work was to evaluate whether the exposure to subcytotoxic concentrations of MCLR was sufficient to induce the proliferation of Vero-E6 cells. Through BrdU incorporation assay we show that at nanomolar concentrations MCLR stimulates cell cycle progression in Vero-E6 kidney cell line. Moreover, the analysis of mitogen-activated protein kinases p38, JNK and ERK1/2 activity revealed that the proliferative effect of MCLR is associated with the activation of the pro-proliferative ERK1/2 pathway. These results emphasise the importance to confirm in vivo the impact of MCLR on tumour promotion at kidney level.
- Nutritional characterization and biological activity of Opuntia ficus-indica (L.) Mill. fruitPublication . Silva, M.A.; Albuquerque, T.G.; Pereira, P.; Ramalho, R.; Costa, H.S.Introduction: Nowadays, consumers demand for foods that contain compounds with enhanced nutritional quality. Opuntia ficus-indica (L.) Mill belongs to the Cactaceae family and is a tropical or subtropical plant that grows wild in the arid and semi-arid regions of the world. However, its nutritional and bioactive potential remains to be exploited. The aim of this study was to evaluate the nutritional composition and biological activity of O. ficus-indica fruit pulp. Materials and Methods: In 2017, the prickly pears were obtained at Herdade de Peliteiros (Silveiras, Montemor-o-Novo, Évora). Nutritional composition was determined according to the methods described by Albuquerque et al. (2016) (1). The energy value and available carbohydrates were calculated (2, 3). Antioxidant activity of prickly pear was determined using two different methods (2,2-diphenyl-1-picryl-hydrazyl (DPPH•) and ferric reduction power (FRAP)) (4). Moreover, total phenolic and total flavonoids contents were also assessed by spectrophotometric methodologies (4). Results: With the results obtained, it was possible to verify that water is the main constituent of the pulp (83%), the energy value was 59 kcal/245 kJ per 100 g of edible portion and total dietary fibre was 4.8 g/100 g of edible portion. The total phenolics content for the analysed prickly pear pulp was 19.8 ± 0.78 mg gallic acid equivalents/g, while the total flavonoid content was 1.70 ± 0.08 mg epicatechin equivalents/g. Regarding the antioxidant activity evaluation, the results obtained for the two different analytical methods applied, were 17.12 ± 0.71 mg/mL and 46.6 ± 1.99 mg Trolox eq./g for DPPH• and FRAP assays, respectively. Discussion and Conclusions: Based on the results obtained for the analysed prickly pear pulp, it is possible to conclude that it is a good source of bioactive compounds and could contribute to the intake of natural antioxidants. It is a fruit with nutritional interest and its use in human diet can bring potential health benefits to consumers.
- Opuntia ficus-indica (L.) Mill. and Annona cherimola Mill. by-products: a potential to be exploitedPublication . Pereira, P.; Albuquerque, T.G.; Silva, M.A.; Ramalho, R.; Oliveira, M.B.P.P.; Costa, H.S.Introduction: Fruits have become increasingly important in human nutrition because of their nutrient and bioactive composition, as well as potential beneficial health effects. Opuntia ficus-indica (L.) Mill. and Annona cherimola Mill. are commonly known as prickly pear and cherimoya, respectively. These exotic fruits are highly appreciated due to their attractive sensorial properties (1). However, considerable quantities of by-products from the production of these fruits are discarded, and these can be a valuable source of bioactive compounds. Therefore, this study aims to perform a comparison between the antioxidant activity, total phenolics, total flavonoids and vitamin C contents of the peels of prickly pear and cherimoya, in order to evaluate their potential to obtain added value natural extracts. Materials and Methods: Samples of cherimoya were supplied by a company located in Madeira Island (Portugal) and samples of prickly pear were obtained at Herdade de Peliteiros (Silveiras, Montemor-o-Novo, Évora, Portugal). Then, samples were manually divided between edible portion (pulp) and non-edible portion (peel). Peels of the selected fruits were analysed concerning: (i) antioxidant activity by radical 2,2-diphenyl-1-picrylhidrazyl (DPPH•) scavenging activity method; (ii) total phenolics determined by Folin-Ciocalteu assay and expressed as mg of gallic acid equivalents (GAE)/g of sample; and (iii) total flavonoids, expressed as mg of epicatechin equivalents (ECE) per g of sample, through the interpolation of the calibration curve of epicatechin (2). Total vitamin C content was determined by high performance liquid chromatography coupled to diode array detection. All analyses were performed in triplicate (1). Results: EC50 is the concentration of the sample that decreases the initial DPPH• absorbance by 50%. Therefore, the highest antioxidant activity was observed for the peel of cherimoya (EC50, 0.18 ± 0.0 mg/mL). With respect to total phenolics, the obtained values were 0.195 ± 0.01 and 49.1 ± 1.0 mg of GAE/g of sample, for cherimoya and prickly pear peels, respectively. Also, prickly pear peel showed the highest total flavonoids content (3.01 ± 0.14 mg ECE/g) and total vitamin C content (132.4 ± 0.61 mg/100 g of sample). Discussion and Conclusions: These results highlight the antioxidant properties of these by-products and support their employment as added value natural extracts in cosmetic, pharmaceutical and food processing industries. Furthermore, this work will contribute to maintain the biodiversity and to promote the sustainable development and exploitation of these exotic fruits.
- Opuntia ficus-indica (L.) Mill.: A Multi-Benefit Potential to Be ExploitedPublication . Silva, M.A.; Albuquerque, T.G.; Pereira, P.; Ramalho, R.; Vicente, F.; Oliveira, M.B.P.P.; Costa, H.S.Consumer interest in foods with enhanced nutritional quality has increased in recent years. The nutritional and bioactive characterization of fruits and their byproducts, as well as their use in the formulation of new food products, is advisable, contributing to decrease the global concerns related to food waste and food security. Moreover, the compounds present in these raw materials and the study of their biological properties can promote health and help to prevent some chronic diseases. Opuntia ficus-indica (L.) Mill. (prickly pear) is a plant that grows wild in the arid and semi-arid regions of the world, being a food source for ones and a potential for others, but not properly valued. This paper carries out an exhaustive review of the scientific literature on the nutritional composition and bioactive compounds of prickly pear and its constituents, as well as its main biological activities and applications. It is a good source of dietary fiber, vitamins and bioactive compounds. Many of its natural compounds have interesting biological activities such as anti-inflammatory, hypoglycemic and antimicrobial. The antioxidant power of prickly pear makes it a good candidate as an ingredient of new food products with fascinating properties for health promotion and/or to be used as natural extracts for food, pharmaceutic or cosmetic applications. In addition, it could be a key player in food security in many arid and semi-arid regions of the world, where there are often no more plants.
- Opuntia ficus-indica (L.) Mill.: Análise nutricional comparativa entre polpa e sub-produtoPublication . Silva, M.A.; Albuquerque, T.G.; Pereira, P.; Vicente, F.; Ramalho, R.; Costa, H.S.Diversos estudos demonstram que o consumo de alimentos ricos em compostos bioativos e antioxidantes está associado à diminuição do risco de doenças cardiovasculares e cancro. Estes nutrientes encontram-se naturalmente presentes nas frutas e têm vindo a suscitar um grande interesse por parte da população devido aos seus potenciais efeitos benéficos na saúde. Opuntia ficus-indica (L.) Mill., também conhecido por figo-da-Índia, é uma espécie da família Cactaceae, amplamente cultivada nas regiões semi-áridas de todo o mundo. O interesse neste fruto tem vindo a aumentar nos últimos anos, principalmente devido às suas propriedades benéficas a nível da saúde. O objetivo deste trabalho foi realizar a análise comparativa do teor de compostos fenólicos, do teor de flavonóides totais e do potencial antioxidante entre a polpa e o sub-produto do Opuntia ficus-indica (L.) Mill.. Em 2017, foram adquiridas amostras do Opuntia ficus-indica (L.) Mill. na Herdade de Peliteiros (Silveiras, Montemor-o-Novo, Évora). A atividade antioxidante foi determinada utilizando dois métodos diferentes (2,2-difenil-1-picril-hidrazilo (DPPH•) e poder de redução férrica (FRAP)). O teor de compostos fenólicos totais foi expresso em equivalentes de ácido gálhico (EAG), enquanto o teor de flavonóides totais foi expresso em equivalentes de epicatequina (EEC). Com os resultados obtidos foi possível observar-se que o sub-produto apresentou um teor mais elevado de compostos fenólicos totais (49,1 ± 1,00 mg EAG/g) e flavonóides totais (3,01 ± 0,14 mg EEC/g), assim como uma maior atividade antioxidante para os dois métodos utilizados, do que a polpa. Tendo por base os resultados obtidos é possível concluir que o Opuntia ficus-indica (L.) Mill. pode ser considerado uma boa fonte de compostos bioativos. Uma vez que é uma fruta com interesse nutricional, a sua inclusão na dieta alimentar pode trazer benefícios para a saúde dos seus consumidores. Por outro lado, o sub-produto do Opuntia ficus-indica (L.) Mill. poderá ser utilizado na formulação de novos produtos alimentares com propriedades antioxidantes relevantes, promovendo também a redução de resíduos alimentares.
- Opuntia ficus-indica L. Mill by-product: valorisation as a new potential food ingredientPublication . Silva, M.A.; Albuquerque, T.G.; Pereira, P.; Ramalho, R.; Costa, H.S.Introduction: Food industry is a very important economic sector and produces many tonnes of food waste, usually known as by-products. One of the concerns of the European Commission is to reduce this waste, therefore in 2012, an action plan was presented to help solve this problem. Nowadays, the use of by-products to formulate new products is becoming a reality. Therefore, it is becoming increasingly important to study the nutritional composition and biological potential of these by-products. Aim: The aim of this study was to provide a bioactivity evaluation of Opuntia ficus-indica L. Mill. by-product (peel) in order to evaluate its potential to be used as a functional ingredient. Methods: In 2017, samples were obtained from Herdade de Peliteiros (Silveiras, Montemor-o-Novo, Évora). The antioxidant capacity was evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH•) and ferric reducing antioxidant power (FRAP) assays. The total phenolic compounds (expressed as mg of gallic acid equivalents (GAE)/g) and the total flavonoids content (expressed as epicatechin equivalents (ECE)/g) were also determined in the selected samples. Results: The results obtained for the total phenolic compounds were 49.1 ± 1.00 mg GAE/g and for the total flavonoids content 3.01 ± 0.14 mg ECE/g. For DPPH• assay, the O. ficus-indica L. Mill. peel presented an EC50 of 5.68 ± 0.28 mg/mL and for FRAP assay 59.7 ± 1.04 mg Trolox equivalents/g. Conclusions: It is possible to conclude that O. ficus-indica L. Mill. peel can be considered a promising source of bioactive compounds. This study contributes to promote the use of O. ficus-indica L. Mill. peel in the formulation of new products, thus promoting the reduction of food waste and the development of new products with relevant antioxidant properties.