Percorrer por autor "Pires, Preciosa"
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- Bioactive and Phenolic Profiles in Pinus pinaster Bark: A Comparative Study of Microwave and Ultrasound Extraction MethodsPublication . Barros, Diana; Alonso-Esteban, José Ignacio; Finimundy, Tiane C.; Pereira, Carla; Vaz, Josiana A.; Pereira-Pinto, Ricardo; Fernandes, Élia; Pires, Preciosa; Santos, Joana; Barros, Lillian; Vaz-Velho, ManuelaThis study conducted a comprehensive comparison of two green extraction methods, microwave-assisted extraction (MAE) and ultrasound-assisted extraction (UAE), for recovering bioactive phenolic compounds from Pinus pinaster bark. The goal was to valorize timber industry waste and enhance the value of by-products through the development of eco-friendly processes to extract phenolic compounds from Pinus pinaster Aiton subsp. atlantica in northwest Portugal. MAE achieved significantly higher extraction yields than UAE (11.13 vs. 3.47 g extract/100 g bark) and superior total phenolic content (833 vs. 514 mg GAE/g). MAE extracts also exhibited enhanced antioxidant activity in most assays tested (DPPH, ABTS, ORAC, and OxHLIA), while both extracts effectively inhibited lipid peroxidation (TBARS) and showed activity against Gram-positive bacteria. Phenolic profile analysis revealed that MAE recovered a substantially higher amount of total phenolic compounds (230.0 mg/g) compared to UAE (86.95 mg/g), with procyanidins identified as the predominant compounds. The greater recovery of this complex procyanidin mixture by MAE is strongly associated with the enhanced bioactivities observed. Overall, this study confirms MAE as a highly efficient and sustainable technology for transforming pine bark waste into valuable antioxidant and antimicrobial extracts with potential applications in the food and pharmaceutical industries.
- Composición de los aditivos en embutido fermentado portugués (chouriço) después del secadoPublication . Pires, Preciosa; Araújo, José Pedro; Barros, M. Teresa; Fernandes, E.; Cerqueira, Joaquim; Cadavez, Vasco; Gonzales-Barron, Ursula; Dias, TeresaChouriço is a Portuguese dry-fermented sausage, which is much appreciated among consumers and highly consumed due to its organoleptic characteristics. Hence, the objective of this study was to investigate the food additive composition in dry products and comparison with the values in UE Regulation. The maximum limits allowed, according to Reg (EU) 1129/2011, are met for nitrite in both factories, with values well below the limit of 150 mg/kg (between 0,42-8,01 mg/kg). For nitrate salts the values are below the maximum limit in one production (between 10,1-22,6 mg/kg) but above the maximum level (> 150mg/kg) in another production (above 164,5 mg/kg). Regarding phosphates, both factories have their products not meeting the EU Reg (> 500 mg / kg). The chouriço is a meat product that can be consumed raw. To this product are added additives which act as antioxidants, in the case of nitrite, and as preventive or inhibitors of microbial growth. The concentrations of these salts have to be controlled, but its positive effects are superimposed on the possibility of problems originated with growth of microorganisms.
- The chemical characterisation of the maritime pine bark cultivated in Northern PortugalPublication . Barros, Diana; Fernandes, Elia; Jesus, Meirielly; Barros, Lillian; Alonso-Esteban, José Ignacio; Pires, Preciosa; Velho, Manuela VazMaritime pine, scientifically known as Pinus pinaster, holds a vital role in Iberian Peninsula forests, primarily as a source of wood for panels, paper, and cellulose production. Recently, there has been a growing interest in utilising agroforestry by-products to yield valuable chemicals for applications in various sectors, including the food, pharmaceutical, and bioenergy industries. This study aimed to assess the value of the primary by-product of Pinus pinaster from the Minho region of northwestern Portugal, i.e., the bark. The research extensively examined the bark’s chemical and thermal characteristics, including ash content, extractives, lignin, cellulose, hemicellulose, fatty acids, and mineral composition. Additionally, various analytical techniques like FTIR, SEM, DSC, DTG, and XRD were used to observe chemical structure differences. The results reveal that the Pinus pinaster bark primarily consists of lignin (51.15%) and holocellulose (46.09%), with extractives mainly soluble in toluene–ethanol, followed by water, and a small amount of them are soluble in ethanol. The bark contained around 0.44% ash, and heavy metals such as Cd and Pb were not found. During degradation, Pinus pinaster experienced a 10% mass loss at 140 °C. In terms of crystallinity, holocellulose and cellulose showed similar percentages at approximately 25.5%, while α-cellulose displayed the highest crystallinity index at 41%.