Browsing by Author "Madureira, Joana"
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- Applications of bioactive compounds extracted from olive industry wastes: A reviewPublication . Madureira, Joana; Margaça, Fernanda M.A.; Santos-Buelga, Celestino; Ferreira, Isabel C.F.R.; Verde, Sandra Cabo; Barros, Lillian; Madureira J.The wastes generated during the olive oil extraction process, even if presenting a negative impact for the environment, contain several bioactive compounds that have considerable health benefits. After suitable extraction and purification, these compounds can be used as food antioxidants or as active ingredients in nutraceutical and cosmetic products due to their interesting technological and pharmaceutical properties. The aim of this review, after presenting general applications of the different types of wastes generated from this industry, is to focus on the olive pomace produced by the two-phase system and to explore the challenging applications of the main individual compounds present in this waste. Hydroxytyrosol, tyrosol, oleuropein, oleuropein aglycone, and verbascoside are the most abundant bioactive compounds present in olive pomace. Besides their antioxidant activity, these compounds also demonstrated other biological properties such as antimicrobial, anticancer, or anti-inflammatory, thus being used in formulations to produce pharmaceutical and cosmetic products or in the fortification of food. Nevertheless, it is mandatory to involve both industries and researchers to create strategies to valorize these byproducts while maintaining environmental sustainability.
- Applications of bioactive compounds extracted from olive industry wastes: a reviewPublication . Madureira, Joana; Margaça, Fernanda M.A.; Santos‐Buelga, Celestino; Ferreira, Isabel C.F.R.; Verde, Sandra Cabo; Barros, LillianThe wastes generated during the olive oil extraction process, even if presenting a negative impact for the environment, contain several bioactive compounds that have considerable health benefits. After suitable extraction and purification, these compounds can be used as food antioxidants or as active ingredients in nutraceutical and cosmetic products due to their interesting technological and pharmaceutical properties. The aim of this review, after presenting general applications of the different types of wastes generated from this industry, is to focus on the olive pomace produced by the two-phase system and to explore the challenging applications of the main individual compounds present in this waste. Hydroxytyrosol, tyrosol, oleuropein, oleuropein aglycone, and verbascoside are the most abundant bioactive compounds present in olive pomace. Besides their antioxidant activity, these compounds also demonstrated other biological properties such as antimicrobial, anticancer, or anti-inflammatory, thus being used in formulations to produce pharmaceutical and cosmetic products or in the fortification of food. Nevertheless, it is mandatory to involve both industries and researchers to create strategies to valorize these byproducts while maintaining environmental sustainability.
- Applications of bioactive compounds extracted from olive industry wastes: a reviewPublication . Madureira, Joana; Margaça, Fernanda M.A.; Santos-Buelga, Celestino; Ferreira, Isabel C.F.R.; Cabo Verde, Sandra; Barros, LillianThe wastes generated during the olive oil extraction process, even if presenting a negative impact for the environment, contain several bioactive compounds that have considerable health benefits. After suitable extraction and purification, these compounds can be used as food antioxidants or as active ingredients in nutraceutical and cosmetic products due to their interesting technological and pharmaceutical properties. The aim of this review, after presenting general applications of the different types of wastes generated from this industry, is to focus on the olive pomace produced by the two-phase system and to explore the challenging applications of the main individual compounds present in this waste. Hydroxytyrosol, tyrosol, oleuropein, oleuropein aglycone, and verbascoside are the most abundant bioactive compounds present in olive pomace. Besides their antioxidant activity, these compounds also demonstrated other biological properties such as antimicrobial, anticancer, or anti-inflammatory, thus being used in formulations to produce pharmaceutical and cosmetic products or in the fortification of food. Nevertheless, it is mandatory to involve both industries and researchers to create strategies to valorize these byproducts while maintaining environmental sustainability.
- Assessment of gamma radiation effects on antioxidant activity of cork wastewaterPublication . Madureira, Joana; Pimenta, Andreia I.; Dias, Maria Inês; Melo, Rita; Santos, Pedro M.P.; Falcão, António N.; Cabo Verde, Sandra; Ferreira, Isabel C.F.R.; Margaça, Fernanda M.A.Cork cooking wastewater results from the process of boiling cork planks. It is an aqueous and complex dark liquor with high concentration of phenolic compounds such as phenolic acids and tannins [1, 2], which are known for their high antioxidant activity. The aim of this work is to perform a compreensive assessment of the effects of gamma radiation on the antioxidant activity of cork cooking water. The irradiation experiments were carried out at room temperature in a Co-60 experimental equipment (Prescisa 22, Graviner, Lda, UK), with an activity of 140 Tbq (3.77 kCi) and at a dose rate of 1.5 kGy/h, located at the Centro de Ciências e Tecnologias Nucleares (Portugal). Samples of wastewater were irradiated at. three distinct. doses (10, 20 and 50 KGy) and the antioxidant activity was evaluated by in vitro assays based on different mechanisms of action: DPPH radical scavenging activity, reducing power and inhibition of β-carotene bleaching. Antioxidant capacity was compared with the physico-chemical characterization [3) of cork wastewater - Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD), Total Suspended Solids (TSS) and Total Phenolic Content. (TP) - when exposed to gamma radiation. The obtained results point out that gamma radiation induces changes in complex compounds leading to an increase in the antioxidant capacity. These results demonstrate the potential of this technology in order to increase the added value of cork wastewaters.
- Coaching laboral a perceção de gestores de pmePublication . Madureira, Joana; Lousada, LigiaO presente estudo tem como objetivo principal analisar e compreender a perceção de diferentes gestores de pequenas e médias empresas (PME) sobre o processo de coaching em contexto empresarial. Para o efeito realizou-se uma revisão de literatura sobre organizações, organizações positivas, clima e cultura organizacionais, formação profissional e sobre o coaching, tema central do estudo. Procurou-se, desta forma, enquadrar o processo de coaching no âmbito das organizações positivas, com uma cultura organizacional adaptativa e estimulante e com práticas formativas convergentes com o desenvolvimento profissional. A metodologia de investigação subjacente ao estudo é de cariz qualitativa, tendo-se utilizado como técnica de recolha de dados a entrevista semiestruturada. Para o efeito, foram realizadas cinco entrevistas a diferentes gestores de PME. Pela análise dos discursos dos entrevistados, os planos de formação profissional das empresas, incidem em áreas técnicas e de desenvolvimento pessoal, verificando-se que apenas uma empresa utiliza o coaching como método de desenvolvimento profissional. As restantes empresas utilizam outros métodos de formação e desenvolvimento, verificando-se no discurso dos gestores uma valorização das soft skills. Os gestores entrevistados consideram o processo de feedback importante para o desenvolvimento profissional dos trabalhadores e admitem que um aspeto a melhorar na relação chefia-trabalhador é o processo de comunicação. A partir da pesquisa realizada é possível perceber que o coaching é uma prática conhecida, mas pouco praticada pelos gestores de PME entrevistados.
- Coaching laboral: uma alternativa para a educação continuadaPublication . Madureira, Joana; Lousada, Lígia Maria; Martins, Oliva M.D.O presente estudo tem como objetivo principal analisar e compreender a perceção de diferentes gestores de Pequenas e Médias empresas (PME) sobre o processo de coaching. Para o efeito, investigou-se sobre as organizações positivas, clima e cultura organizacionais, formação profissional e coaching, tema central do estudo. Procurou-se enquadrar o processo de coaching no âmbito das organizações positivas, caracterizadas por uma cultura organizacional adaptativa e estimulante, e com práticas formativas convergentes com o desenvolvimento profissional. A metodologia de investigação subjacente ao estudo é de cariz qualitativa, tendo-se utilizado como técnica de recolha de dados a entrevista semiestruturada. Para o efeito, foram realizadas cinco entrevistas a diferentes gestores de empresas. Pela análise dos discursos dos entrevistados, pode afirmar-se que os planos de formação profissional das empresas, incidem em áreas técnicas e de desenvolvimento pessoal, verificando-se que apenas uma empresa utiliza o coaching como método de desenvolvimento profissional. As restantes empresas utilizam outros métodos de formação e desenvolvimento de competências, verificando-se, no discurso dos entrevistados uma valorização das soft skills e não apenas de competências técnicas. Os gestores entrevistados consideram o processo de feedback importante para o desenvolvimento profissional dos trabalhadores e admitem que um aspeto a melhorar na relação chefia-trabalhador é o processo de comunicação. A partir da pesquisa realizada é possível perceber que o coaching é uma prática conhecida, mas pouco praticada pelos gestores de PME entrevistados, sendo que para a maioria, esse conhecimento resulta apenas de “ouvir falar”
- Degradation of compounds present in cork boiling water by gamma radiationPublication . Madureira, Joana; Barros, Lillian; Melo, Rita; Santos, Pedro M.P.; Falcão, António N.; Cabo Verde, Sandra; Ferreira, Isabel C.F.R.; Margaça, Fernanda M.A.Cork boiling water is an aqueous and complex dark liquor with high concentration of phenolic compounds such as phenolic acids and tannins [1, 2], which are considered biorecalcitrants [2]. Ionizing radiation has been widely studied as an alternative technology for the degradation of organic contaminants without the addition of any other (e.g.: Fenton technologies). The aim of this work was to identify the compounds present in cork boiling water and further evaluate the resulting stable degradation products after gamma irradiation. The irradiation experiments of standard solutions were carried out at room temperature using a Co-60 experimental equipment. The applied absorbed doses were 20 and 50 kGy at a dose rate of 1.5 kGy/h, determined by routine dosimeters [3]. The identification of radiolytic products was carried out by HPLC-DAD-ESI/MS. The phenolic compounds were identified by comparing their retention times and UV–vis and mass spectra with those obtained from standard compounds, when available, as well as by comparing the obtained information with available data reported in the literature. Concerning the obtained results and the literature review, the main cork wastewater components are: quinic, gallic, protocatechuic, vanillic, syringic and ellagic acids. Based on this, we used protocatechuic, vanillic and syringic acids as model compounds to study their degradation by gamma radiation in order to identify the corresponding radiolytic products. Standard aqueous solutions were irradiated and the derivatives of each model compound are represented in figure 1. The obtained results seem to demonstrate that the derivatives of the parent compounds could also be phenolic acids, since it was observed the loss of 44 u (CO2) from the [M-H]- ions. Gallic and protocatechuic acids are identified as derivatives of vanillic and syringic acids, and gallic acid as a protocatechuic acid derivative. Compound 5 ([M-H]- at m/z 169) was tentatively identified as 2,4,6-trihydroxybenzoic acid, since its fragmentation pattern (m/z 151, 125 and 107) is similar to that previously reported in literature [4]. The structure of compound 7 was proposed based on the molecular ion and its fragmentation and compound 6 remains unknown.
- Degradation of phenolic acids by gamma radiation as model compounds of cork wastewatersPublication . Madureira, Joana; Barros, Lillian; Melo, Rita; Cabo Verde, Sandra; Ferreira, Isabel C.F.R.; Margaça, Fernanda M.A.The degradation by gamma radiation of four phenolic compounds (gallic acid, protocatechuic acid, vanillic acid and syringic acid) present in cork wastewaters was studied in several treatment conditions. The irradiations were performed under different pH (natural, 3, 7 and 10) and atmospheres (aerated, N2O and O2) for isolated and aqueous mixture solutions of standard phenolic acids. The degradation of the compounds was higher in isolated than in the mixture solutions indicating a protective effect in the quaternary mixture solution. The saturation with N2O promoted the highest degradation rates for all phenolic acids in the mixture. However, at natural pH and in air it was achieved degradation efficiencies>50% for gallic, vanillic and syringic acids in isolated and mixture solutions for a treatment dose of 20 kGy. It was verified that some of the compounds are a degradation product of the others, for example gallic acid was found to be a radiolytic product of syringic, vanillic and protocatechuic acids. Two different compounds were identified as radiolytic products of the studied phenolic acids, and their fragmentation pathways were proposed. The results highlighted that ionizing radiation could be used as clean technology for pollutants degradation using doses of 20 kGy.
- Effect of gamma radiation on bioactive compounds of olive wastesPublication . Madureira, Joana; Dias, Maria Inês; Barros, Lillian; Santos-Buelga, Celestino; Margaça, Fernanda M.A.; Ferreira, Isabel C.F.R.; Cabo Verde, SandraThe olive pomace is an environmentally detrimental residue from olive oil industry. This residue contains large amounts of bioactive compounds, such as hydroxytyrosol and tyrosol, secoiridoid derivatives, phenolic acids and flavonoids1 that might be used by the food industry as preservatives. The aim of this work was to study the gamma radiation potential to improve the extractability of the bioactive compounds present in olive wastes. Gamma radiation is an eco-friendly technology that can be used to enhance the benefic properties of different agro-industrial products. Olive pomace samples (crude olive pomace - COP - and extracted olive pomace - EOP) were collected from UCASUL - União de Cooperativas Agrícolas do Sul, located in Alentejo region, in Portugal. The irradiation experiments were carried out at room temperature in a Co-60 semi-industrial facility (absorbed doses: 5-22 kGy; dose rate: 16 kGy/h). The characterization of the phenolic profile in the extracts of olive pomace and the identification of the radiolytic products were carried out by HPLC-DAD-ESI/MS2. The major phenolic compounds present in olive pomace extracts were hydroxytyrosol, hydroxytyrosol-1-β-glucoside, tyrosol, syringic acid and luteolin-7-O-rutinoside. Caffeic acid, vanillin, verbascoside and its derivatives and oleuropein aglycons were also found in the extracts although in lower concentrations. The obtained results demonstrated that gamma radiation significantly improved the extraction of phenolic compounds from both olive pomace extracts, obtaining the highest yield at 10 kGy for EOP and at 22 kGy for COP. At these doses, the total concentration of phenolic compounds in the extracts was 159±7 mg/g in the EOP and 161±2 mg/g in the COP ones. Comparing with non-irradiated samples, these values represent an increase in extractable phenolic compounds of 2.5 and 2.4 fold, respectively. Nevertheless, for EOP it was found that an absorbed dose of 5 kGy was capable to increase the phenolic content with no significant difference from the higher applied doses. These results demonstrated that gamma radiation could be a suitable technology for the valorization of olive oil by-products, contributing to enhance extraction of phenolic compounds. This outcome can help the olive oil industry to adopt clean processes and promote the sustainable development.
- Effect of olive pomace extract application and packaging material on the preservation of fresh-cut royal gala applesPublication . Madureira, Joana; Melgar Castañeda, Bruno; Alves, Vitor D.; Moldão-Martins, Margarida; Margaça, Fernanda M.A.; Santos-Buelga, Celestino; Barros, Lillian; Verde, Sandra CaboThe efficiency of natural olive pomace extracts for enhancing the quality of fresh-cut apples was compared with commercial ascorbic acid and two different packaging films (biodegradable polylactic acid (PLA) and oriented polypropylene (OPP)) were tested. The composition of atmosphere inside the packages, the physicochemical parameters (firmness, weight loss and color), the microbial load, total phenolic content and antioxidant activity of fresh-cut apples were evaluated throughout 12 days of storage at 4 degrees C. After 12 days of refrigerated storage, a significant decrease in O-2 was promoted in PLA films, and the weight loss of the whole packaging was higher in PLA films (5.4%) than in OPP films (0.2%). Natural olive pomace extracts reduced the load of mesophilic bacteria (3.4 +/- 0.1 log CFU/g and 2.4 +/- 0.1 log CFU/g for OPP and PLA films, respectively) and filamentous fungi (3.3 +/- 0.1 log CFU/g and 2.44 +/- 0.05 log CFU/g for OPP and PLA films, respectively) growth in fresh-cut apples after five days of storage at 4 degrees C, and no detection of coliforms was verified throughout the 12 days of storage. In general, the olive pomace extract preserved or improved the total phenolic index and antioxidant potential of the fruit, without significant changes in their firmness. Moreover, this extract seemed to be more effective when combined with the biodegradable PLA film packaging. This work can contribute to the availability of effective natural food additives, the sustainability of the olive oil industries and the reduction of environmental impact. It can also be useful in meeting the food industries requirements to develop new functional food products.
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