Browsing by Author "Silva, A.S."
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- Avaliação de ácidos gordos trans, gordura saturada e sal em alimentos processados: estudo do panorama português (PTranSALT)Publication . Albuquerque, T.G.; Costa, H.S.; Silva, A.S.
- Detection of the Invasive Mosquito Species Aedes (Stegomyia) albopictus (Diptera: Culicidae) in PortugalPublication . Osório, H.C.; Zé-Zé, L.; Neto, M.; Silva, S.; Marques, F.; Silva, A.S.; Alves, M.J.The Asian tiger mosquito Aedes albopictus is an invasive mosquito originating from the Asia-Pacific region. This species is of major concern to public and veterinary health because of its vector role in the transmission of several pathogens, such as chikungunya, dengue, and Zika viruses. In Portugal, a National Vector Surveillance Network (REde de VIgilância de VEctores—REVIVE) is responsible for the surveillance of autochthonous, but also invasive, mosquito species at points of entry, such as airports, ports, storage areas, and specific border regions with Spain. At these locations, networks of mosquito traps are set and maintained under surveillance throughout the year. In September 2017, Ae. albopictus was detected for the first time in a tyre company located in the North of Portugal. Molecular typing was performed, and a preliminary phylogenetic analysis indicated a high similarity with sequences of Ae. albopictus collected in Europe. A prompt surveillance response was locally implemented to determine its dispersal and abundance, and adult mosquitoes were screened for the presence of arboviral RNA. A total of 103 specimens, 52 immatures and 51 adults, were collected. No pathogenic viruses were detected. Despite the obtained results suggest low abundance of the population locally introduced, the risk of dispersal and potential establishment of Ae. albopictus in Portugal has raised concern for autochthonous mosquito-borne disease outbreaks.
- Green tea extract and nanocellulose embedded into polylactic acid film: properties and efficiency on retarding the lipid oxidation of a model fatty foodPublication . Vilarinho, F.; Stanzione, M; Buonocore, G; Vaz, F; Silva, A.S.Eco-friendly and antioxidant bioactive films based on polylactic acid (PLA), loaded with cellulose nanocrystals (CNC) and green tea extract (GTE) were prepared by direct melt processing. GTE was chemically characterized by using high performance liquid chromatography (HPLC), coupled with tandem mass spectrometry. The antioxidant, physical, thermal, mechanical and microstructural properties of the produced films were investigated. The efficiency of the active films on retarding the lipid oxidation of the salami, was evaluated by the thiobarbituric acid reactive substances (TBARS) and p-anisidine value. Experimental results highlight that the PLA/ 2%CNC/1%GTE nanocomposite film (film containing 2 wt% of CNC and 1 wt% of GTE) shows the highest reduction in terms of oxygen transmission ratio and water vapor permeability (60 % and 33 % respectively) and the optimal macroscopic mechanical behavior. However, it shows a slight antioxidant activity only at short storage time, namely 7 and 15 days. Overall, PLA/2CNC nanocomposite film exhibits the best compromise in terms of improvement of material properties and of effectiveness in retarding lipid oxidation at short and long storage time, mainly related to its enhanced barrier properties.
- LDPE and PLA Active Food Packaging Incorporated with Lemon by-Products Extract: Preparation, Characterization and Effectiveness to Delay Lipid Oxidation in Almonds and Beef MeatPublication . Andrade, M.A.; Barbosa, C.H.; Mariño-Cortegoso, S.; Barbosa-Pereira, L.; Sendón, R.; Buonocore, G.G.; Stanzione, M.; Coelho, A.; Correia, C.B.; Saraiva, M.; Quirós, A.R.; Vilarinho, F.; Khwaldia, K.; Silva, A.S.; Ramos, F.Low-density polyethylene-based packaging with 4% lemon extract (LDPE/4LE) and two polylactic-based (PLA) packaging materials with 4% and 6% lemon extract (PLA/PEG/4LE and PLA/6LE) were produced. O2 and water permeability tests were performed, the total and individual phenolic compounds content were measured, and the films’ antioxidant activities were determined. The films’ ability to delay lipid oxidation was tested in two model foods: almonds, packaged with LDPE/4LE, PLA/4LE and PLA/6LE for a maximum period of 60 days at 40 °C (accelerated assay); and beef meat, packaged with the PLA/6LE for a maximum period of 11 days at 4 °C. The LE improved the WVP in all of the active films by 33%, 20% and 60% for the LDPE/4LE, PLA/4LE and PLA/6LE films, respectively. At the end of 10 days, the migration of phenolic compounds through the PLA films was measured to be 142.27 and 114.9 μg/dm2 for the PLA/4LE and PLA/6LE films, respectively, and was significantly higher than phenolic compounds migration measured for the LDPE/4LE (15.97 μg/dm2). Naringenin, apigenin, ferulic acid, eriocitrin, hesperidin and 4-hydroxybenzoic acid were the main identified compounds in the PLA, but only 4-hydroxybenzoic acid, naringenin and p-coumaric acid were identified in the LDPE films. Regarding the films’ ability to delay lipid oxidation, LDPE/4LE presented the best results, showing a capacity to delay lipid oxidation in almonds for 30 days. When applied to raw beef meat, the PLA/6LE packaging was able to significantly inhibit lipid oxidation for 6 days, and successfully inhibited total microorganisms’ growth until the 8th day of storage.