Browsing by Author "Silva, Adriana"
Now showing 1 - 5 of 5
Results Per Page
Sort Options
- Comparative insight upon chitosan solution and chitosan nanoparticles application on the phenolic content, antioxidant and antimicrobial activities of individual grape components of Sousão varietyPublication . Silva, Vanessa; Singh, Rupesh Kumar; Gomes, Nelson; Soares, Bruno Gonçalves; Silva, Adriana; Falco, Virgílio; Capita, Rosa; Alonso-Calleja, Carlos; Pereira, José Eduardo; Amaral, Joana S.; Igrejas, Gilberto; Poeta, PatríciaChitosan, a natural polysaccharide, has been previously proposed as an elicitor in plants to prevent pathogen infections. The present study aimed to analyze the e ect of chitosan solution and chitosan nanoparticles treatment applied on the grapevine variety Sousão with respect to the phenolic composition, antioxidant potential and antibacterial activity of its individual grape components. Grapevine plants of selected lines were sprayed with chitosan solution and chitosan nanoparticles, and ethanolic extracts of stems, seeds and skins were prepared from grapevines treated and not treated with chitosan. Total phenolic, anthocyanin and tannin contents were studied, and the identification of the individual phenolic compounds was performed by HPLC-DAD. The antimicrobial susceptibility method was performed using the Kirby-Bauer disc di usion method against multidrug-resistant bacteria. Overall, there was small increase in the concentration of phenolic compounds, antioxidant and antimicrobial activities in grape components treated with chitosan solution. Seed extracts showed the highest antioxidant and antimicrobial activities. The studied individual components obtained from chitosan-treated grapevines could represent an added value due to the increased antioxidant and antibacterial potentials. The phenolic compounds found in components may be used in food and pharmaceutical industries as natural food preservers and antibiotic adjuvants.
- Consumo de peixe por parte dos estudantes do Instituto Politécnico de BragançaPublication . Silva, Adriana; Rodrigues, Andreia; Martins, Daniela; Fernandes, António; Ferro-Lebres, VeraFish is an important part of a healthy diet, the possibility of substituting meals with a higher content of saturated fat raising cardiovascular diseases risk, by meals with fish has innumerous health benefits. Objective This study aimed to study the consumption of fish in higher education students, and its socio demographic cofactors. Methods A sample of 238 Portuguese higher education students was used in a cross sectional study. A questionnaire regarding socio demographic and fish consumption habits was used. Statistical data analysis was performed suing Statistical Package for Social Sciences, version 21.0. Kolmogorov-Smirnov with Lilliefors correction, Levene, Wilcoxon and Kruskal-Wallis, were the tests used. Results Results revealed that females and students from up-country have a significantly higher consumption of fish. It was also evident that students consume significantly more fish when eating out. Conclusions These data were consistent with previous researches that concluded that women consume significantly more fish and other healthy food items, like fruits and vegetables. These results suggest that the contexts of a fishy diet in higher education students are not the same as for adults. Further studies regarding the determinants of a healthy diet as a whole are needed.
- Evaluation of the phenolic profile of Castanea sativa mill. By-products and their antioxidant and antimicrobial activity against multiresistant bacteriaPublication . Silva, Vanessa; Falco, Virgílio; Dias, Maria Inês; Barros, Lillian; Silva, Adriana; Capita, Rosa; Alonso-Calleja, Carlos; Amaral, Joana S.; Igrejas, Gilberto; Ferreira, Isabel C.F.R.; Poeta, PatríciaThe chestnut industry generates a large amount of by-products. These agro-industrial wastes have been described as potential sources of phenolic compounds with high bioactive potential. Therefore, we aimed to extract the phenolic compounds from chestnut by-products and assess their antioxidant potential and evaluate their antimicrobial activity against multidrug resistant bacteria. The individual phenolic compounds in the ethanolic extracts of chestnut shell, inner shell, bur, and leaves were characterized by HPLC-DAD/electrospray ionization (ESI)-MS. The antioxidant properties were determined by DPPH and ABTS assays. The minimum inhibitory concentration (MIC) and the antimicrobial susceptibility was performed using the Kirby–Bauer disc di usion method against 10 bacterial strains. The major phenolic compounds identified in the extracts were trigalloyl-HHDP-glucose, gallic acid, quercetin, and myricetin glycoside derivatives. All chestnut by-products presented promising antioxidant activity in both assays, with leaf samples the ones presenting the highest antioxidant capacity. The inner shell’s extract was e ective against all Gram-positive and two Gram-negative bacteria; nevertheless, all extracts showed antibacterial activity. Staphylococcus epidermidis showed susceptibility to all extracts while none of the extracts was able to suppress the growth of Escherichia coli and Salmonella enteritidis. Chestnut by-products are a source of phenolic compounds with prominent antioxidant and antimicrobial activities. Nevertheless, further studies should be conducted to assess the correlation between phenolic compounds and the bioactivities obtained.
- Fish consumption in college studentsPublication . Silva, Adriana; Rodrigues, Andreia; Martins, Daniela; Fernandes, António; Ferro-Lebres, VeraFish is an important part of a healthy diet, the possibility of substituting meals with a higher content of saturated fat raising cardiovascular diseases risk, by meals with fish has innumerous health benefits. Objective This study aimed to study the consumption of fish in higher education students, and its socio demographic cofactors. Methods A sample of 238 Portuguese higher education students was used in a cross sectional study. A questionnaire regarding socio demographic and fish consumption habits was used. Statistical data analysis was performed suing Statistical Package for Social Sciences, version 21.0. Kolmogorov-Smirnov with Lilliefors correction, Levene, Wilcoxon and Kruskal-Wallis, were the tests used. Results Results revealed that females and students from up-country have a significantly higher consumption of fish. It was also evident that students consume significantly more fish when eating out. Conclusions These data were consistent with previous researches that concluded that women consume significantly more fish and other healthy food items, like fruits and vegetables. These results suggest that the contexts of a fishy diet in higher education students are not the same as for adults. Further studies regarding the determinants of a healthy diet as a whole are needed.
- Screening of chemical composition, antimicrobial and antioxidant activities in pomegranate, quince, and persimmon leaf, peel, and seed: valorization of autumn fruits by-products for a one health perspectivePublication . Silva, Vanessa; Silva, Adriana; Ribeiro, Jessica; Aires, Alfredo; Carvalho, Rosa Paula; Amaral, Joana S.; Barros, Lillian; Igrejas, Gilberto; Poeta, PatríciaAntimicrobial resistance is increasing globally and is now one of the major public health problems. Therefore, there is a need to search for new antimicrobial agents. The food industry generates large amounts of by-products that are rich in bioactive compounds, such as phenolic compounds, which are known to have several health benefits, including antioxidant and antimicrobial properties. Thus, we aimed to characterize the phenolic compounds present in pomegranate, quince, and persimmon by-products, as well as their antioxidant and antimicrobial activities. Phenolic compounds were extracted from pomegranate, quince, and persimmon leaves, seeds, and peels using a mixture of ethanol/water (80/20). The polyphenol profile of the extracts was determined by high-performance liquid chromatography. The antioxidant activity of the extracts was determined by the 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), and cupric reducing antioxidant capacity (CUPRAC) methods. Antimicrobial susceptibility was evaluated using the Kirby–Bauer disk diffusion method. In general, leaves showed higher concentrations of phenolics than the peel and seeds of fruits. In total, 23 phenolic compounds were identified and quantified, with sanguiin and apigenin-3-O-galactoside being present in the highest concentrations. Leaf extracts of pomegranate showed higher antioxidant activities than the other components in all methods used. In general, all extracts had a greater antimicrobial activity against Gram-positive bacteria. Persimmon leaf and seed extracts inhibited a greater number of bacteria, both Gram-positive and -negative. The lowest minimum inhibitory concentration (MIC) detected among Gram-positive and -negative bacteria was 10 mg/mL for pomegranate peel and leaf extracts against Staphylococcus aureus and S. pseudintermedius and for pomegranate leaf extract against Escherichia coli. Our results reinforce the need to value food industry by-products that could be used as food preservatives and antibiotic adjuvants against multiresistant bacteria.