Browsing by Author "Barros, Lillian"
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- Alginate edible films containing essential oils: characterization and bioactive potentialPublication . Lopes, Ana I.; Melo, Adma; Afonso, Tiago B.; Silva, Sara; Barros, Lillian; Tavaria, Freni K.; Pintado, ManuelaEssential oils (EOs) are natural substances rich in phenolic compounds with notable antimicrobial and antioxidant properties. However, they present some limitations, such as low stability and bioavailability. Incorporating EOs into polymeric films offers a novel approach to overcome these challenges while enhancing their efficacy. In this study, we produced and thoroughly characterized alginate-based edible films incorporated with five different EOs—rosemary, eucalyptus, oregano, sage, and thyme. This is the first comprehensive investigation to include this diverse range of EOs in alginate films. Their antimicrobial and antioxidant activities were also evaluated. The results demonstrated that alginate films containing EOs exhibited significant bioactive properties. Notably, the film incorporated with oregano EO completely inhibited the growth of all tested bacteria and fungi and showed the highest antioxidant activity. Based on these findings, alginate films containing EOs present promising bioactive potential and could serve as biodegradable alternatives to conventional packaging materials, reducing environmental impact. However, further studies are necessary to assess their safety profile and confirm their viability as replacements for traditional food packaging. Future research should focus on evaluating cytotoxicity, genotoxicity, and the practical application of these films in food matrices.
- Antimicrobial activity of alginate films and coatings: a comparisonPublication . Lopes, Ana Isabel; Melo, Adma; Pereira, Eliana; Caleja, Cristina; Barros, Lillian; Tavaria, Freni; Pintado, Manuela
- Antimicrobial activity of an edible film incorporated with oregano essential oilPublication . Lopes, Ana Isabel; Melo, Adma; Pereira, Eliana; Caleja, Cristina; Barros, Lillian; Tavaria, Freni; Pintado, Manuela
- Antimicrobial activity of an edible film incorporated with oregano essential oilPublication . Lopes, Ana Isabel; Melo, Adma; Pereira, Eliana; Caleja, Cristina; Barros, Lillian; Tavaria, Freni; Pintado, Manuela
- Antioxidant activity of alginate edible films containing plant extractsPublication . Lopes, Ana Isabel; Silva, Sara; Barros, Lillian; Caleja, Cristina; Pereira, Eliana; Tavaria, Freni K.; Pintado, ManuelaNowadays, food packaging has been the target of increasing attention. Traditional food packaging is usually made of plastic and accounts for 36.9% of the plastics’ demand, being considered the largest market for plastic industry. Additionally, plastics are mostly produced with polymers from non-renewable sources and so, they contribute to environmental pollution. A way to circumvent this problem is the development of edible films. Edible films can act as complements to traditional plastics because their functional properties are able to extend food’s shelf-life1.Plant extracts are obtained by plants and possess antioxidant activity because of their high concentrations of phenolic compounds. They can be effective at low concentrations, are cost-effective and easy to apply, presenting low toxicity levels and high stability during processing and may not affect the sensory characteristics of food products2.The addition of plant extracts to edible films confers them the ability to act as food preservatives because they present antimicrobial activity against a broad spectrum of food poisoning microorganisms and antioxidant properties that helps to avoid the deterioration of fats and other food constituents 3. So, the main objective of this work was to evaluate the antioxidant activity of alginate edible films containing extracts of licorice (Glycyrrhiza glabra L.), eucalyptus (Eucalyptus globulus Labill.) and sage (Salvia officinalis L.). The 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2-difenil-1-picrilhidrazil (DPPH) scavenging tests were performed on the films and the results show that the films incorporated with plant extracts present antioxidant activity when compared to the control (alginate film without plant extract).The film incorporated with sage extract was the one that presented the best antioxidant activity by both ABTS (4024,169 Trolox equivalents (M)/mg film) and DPPH (3954,813 Trolox equivalents (M)/mg film), followed by the film with eucalyptus extract (ABTS: 3706,291 Trolox equivalents (M)/mg film; DPPH: 3706,291 Trolox equivalents (M)/mg film). On the other hand, the film incorporated with licorice extract (ABTS: 942,5195 Trolox equivalents (M)/mg film; DPPH: 1040,669 Trolox equivalents (M)/mg film) was the one with least antioxidant activity.
- Antioxidant activity of alginate edible films containing plant extractsPublication . Lopes, Ana Isabel; Silva, Sara; Barros, Lillian; Caleja, Cristina; Pereira, Eliana; Tavaria, Freni; Pintado, ManuelaNowadays, food packaging has been the target of increasing attention. Traditional food packaging is usually made of plastic and accounts for 36.9% of the plastics’ demand, being considered the largest market for plastic industry. Additionally, plastics are mostly produced with polymers from non-renewable sources and so, they contribute to environmental pollution. A way to circumvent this problem is the development of edible films. Edible films can act as complements to traditional plastics because their functional properties are able to extend food’s shelf-life1. Plant extracts are obtained by plants and possess antioxidant activity because of their high concentrations of phenolic compounds. They can be effective at low concentrations, are cost-effective and easy to apply, presenting low toxicity levels and high stability during processing and may not affect the sensory characteristics of food products2. The addition of plant extracts to edible films confers them the ability to act as food preservatives because they present antimicrobial activity against a broad spectrum of food poisoning microorganisms and antioxidant properties that helps to avoid the deterioration of fats and other food constituents 3. So, the main objective of this work was to evaluate the antioxidant activity of alginate edible films containing extracts of licorice (Glycyrrhiza glabra L.), eucalyptus (Eucalyptus globulus Labill.) and sage (Salvia officinalis L.). The 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2-difenil-1-picrilhidrazil (DPPH) scavenging tests were performed on the films and the results show that the films incorporated with plant extracts present antioxidant activity when compared to the control (alginate film without plant extract). The film incorporated with sage extract was the one that presented the best antioxidant activity by both ABTS (4024,169 Trolox equivalents (M)/mg film) and DPPH (3954,813 Trolox equivalents (M)/mg film), followed by the film with eucalyptus extract (ABTS: 3706,291 Trolox equivalents (M)/mg film; DPPH: 3706,291 Trolox equivalents (M)/mg film). On the other hand, the film incorporated with licorice extract (ABTS: 942,5195 Trolox equivalents (M)/mg film; DPPH: 1040,669 Trolox equivalents (M)/mg film) was the one with least antioxidant activity.
- Antioxidant activity, phenolic profile, cytotoxicity and genotoxicity of plant extractsPublication . Melo, Adma N. F. de; Afonso, Tiago B.; Ribeiro, Tânia; Machado, Manuela; Carvalho, Marta; Carocho, Márcio; Tavaria, Freni; Teixeira, Paula; Barros, Lillian; Pintado, ManuelaThe outbreak of COVID-19 disease caused by SARS-CoV-2 forced the scientific world to search for new alternatives to help control the virus. Plant extracts have natural compounds that might provide a starting point for the research on the use of plants as an excellent source of new antiviral agents against viruses, including COVID-19 to be included in disinfectants, fabrics or other materials. In this study, the polyphenols content (Folin-Ciocalteu), antioxidant capacity (DPPH, ABTS and ORAC) and the phenolic profile (HPLC) of different hydroethanolic (ethanol:H2O 50:50 v/v) extracts of medicinal plants cultivated under controlled conditions in Portugal (echinacea, rosemary, laurel, thyme and rock rose) were determined, as well as the cytotoxicity effect against a keratinocyte cell line using cell viability assay by PrestoBlue and genotoxicity effect using the AMES test. According to the results, total phenolic content ranged from 204.54 ± 1.78 / 274.20 ± 3.14 (mg EAG/g extract) with the rock rose extract presenting the highest content (p < 0.05). The extracts showed a good antioxidant capacity demonstrated by the high values found for ORAC, which ranged 2855.03 ± 9.75 / 5285.35 ± 60.04 µMol Trolox/mg extract. HPLC analysis revealed the presence of different compounds in the extracts such as the kaempferol-O-glucuronide, catechin, protocatechuic acid and galloyl glucoside, representing a potential source of bioactive components with antioxidant capacity. No toxicity was observed towards the keratinocyte cells and none of them showed mutagenic effects. Based on the results of safety and high polyphenols content of the extracts they demonstrate a great potential as antimicrobial agents. This will allow the design of new experiments aimed at evaluating the antiviral activity of these extracts, especially against SARS-CoV-2.
- Antioxidant activity, phenolic profile, cytotoxicity and genotoxicity of plant extractsPublication . Melo, Adma N. F. de; Afonso, Tiago B.; Ribeiro, Tânia; Machado, Manuela; Carvalho, Marta; Carocho, Márcio; Tavaria, Freni; Carvalho, Marta; Teixeira, Paula; Barros, Lillian; Pintado, Manuela
- Application of encapsulated tomato by-product extract as a colorant in mascarponePublication . Molina, Adriana K.; Leichtweis, Maria G.; Machado, Manuela; Silva, Sara; Pintado, Manuela; Barreira, João C. M.; Dias, Maria Inês; Prieto, Miguel Á.; Barros, Lillian; Pereira, CarlaAgricultural by-products, often underutilized, represent a significant opportunity to obtain sustainable value-added products to develop new functional foods. In this context, the (typically discarded) aerial parts of tomato plants (Solanum lycopersicum L. var. cerasiforme), were studied as new sources of natural bioactive compounds, focusing the extraction and encapsulation (using spray drying with maltodextrin as the encapsulant) of chlorophylls. The encapsulated natural colorant was subsequently incorporated into mascarpone cheese to assess its stability and effect on nutritional and antioxidant properties. The obtained extracts were mainly characterized by high concentrations of bioactive compounds, particularly quercetin-3-O-deoxyhexoside (14.4 ± 0.3 mg/g). The colorant imparted a greener hue to the mascarpone (a* –6.0 ± 0.05 vs. –1.7 ± 0.05 in control, p < 0.001) and maintained antioxidant activity (OxHLIA EC₅₀ = 1440 ± 72 to 1166 ± 66 μg/mL, p = 0.030) without altering the nutritional profile (p > 0.05). Moreover, no cytotoxicity was observed, and the fatty acid composition remained unchanged. Accordingly, the studied encapsulated colorant might be used as a functional ingredient in other dairy products, imparting an attractive color while preserving nutritional integrity. In conclusion, the incorporation of TAPC is an effective strategy to enrich dairy products with natural pigments and bioactive compounds without compromising quality. Future research is needed to explore its application in other food matrices and assess long-term storage effects.
- Chemical characterization, cytotoxic evaluation and anti-SARS-CoV2 activity of plant extracts rich in hydrolysable tanninsPublication . Melo, Adma N. F.; Afonso, Tiago B.; Carvalho, Marta; Rodrigues, Cláudia; Ribeiro, Tânia; Carocho, Márcio; Pinto, Miguel Marques; Tavaria, Freni; Teixeira, Paula; Simas, J. Pedro; Barros, Lillian; Pintado, Manuela