Natália L. Seixas

Mrs. Natália L. Seixas

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Research Focus & Metrics

Academic Career Length

4Years (2023-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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3 April 2025 in Foods
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OPOana-Elena Pascariu
Oana-Elena Pascariu
Leticia M. EstevinhoLeticia M. Estevinho
Leticia M. Estevinho
Natália L. SeixasNatália L. Seixas
Natália L. Seixas
IDIoan Dopcea
Ioan Dopcea
OBOana-Alina Boiu-Sicuia
Oana-Alina Boiu-Sicuia
FIFlorentina Israel
Florentina Israel
This study examines the impact of added elderberry (EDB) extract on the physico-chemical, microbiological, and sensory properties of yogurt over a 21-day storage period. Two separate experiments were conducted: the first focused on testing concentrations of 0.05%, 0.1%, 0.2%, and 0.5% (w/w) EDB extract for impoving antioxidant properties and replacing potassium sorbate, a chemical preservative commonly used in dairy products, while the second aimed to enhance the bioactive compounds’ concentration by adding 0.5% EDB extract, and to assess the effect of a sweetener (agave syrup) on the sensory profile. Both experimental approaches demonstrated a significant increase (p < 0.01) in total phenolic content. In the first experiment, there was approximately 2.6 times more total phenolic content compared to the control (with a maximum of 11.71 mg GAE/100 g for the sample with 0.2% EDB extract), and about 6 times more with the addition of 0.5% EDB extract and agave syrup (with a maximum of 25.29 mg GAE/100 g). Additionally, the IC50 value decreased for all samples with EDB extract, suggesting enhanced antioxidant activity. Specifically, the antioxidant activity was approximately 3.3 times higher for the control for samples obtained from homemade yogurt with EDB extract, and about 8 times higher for samples obtained by adding EDB extract to commercial yogurt, compared to their respective controls. The high stability of bioactive compounds during the storage period highlights the potential of EDB extract as a functional antioxidant ingredient. Microbiological analysis confirmed the safety of the yogurt, with lactic acid and mesophilic bacteria showing stable counts and minimal declines over time. In the first experiment, a reduction of about 2.3 CFU/g was observed from day 0 to day 21 in samples with 0.1% and 0.2% EDB extract, while the control sample showed a reduction of 1.84 CFU/g. However, the control sample recorded the growth of psychrophilic bacteria, yeasts, and molds. In the second experiment, the samples with 0.5% EDB extract showed an average reduction of approximately 0.35 CFU/g, while the control showed a reduction of 0.51 CFU/g, maintaining stable counts and no detectable growth of psychrophilic bacteria, yeasts, molds, or coliforms. Additionally, the inclusion of different concentrations of EDB extract, along with the combination of a higher concentration of EDB extract and agave syrup, improved the yogurt’s sensory attributes, thereby enhancing consumer acceptance. For the first experiment, 68% of the panelists expressed their preference for the samples with EDB extract, and 10% preferred the control sample. In the second experiment, 49% preferred the sample with 0.5% EDB extract and agave syrup, while 23% preferred the control sample. These findings support the integration of EDB extract into yogurt formulations to boost antioxidant properties while preserving microbiological stability. Future research should explore the potential health benefits and long-term effects of these functional dairy products.

15 May 2023 in Food Research International
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Journal Article
Closed access
Ofélia AnjosOfélia Anjos
Ofélia Anjos
Natália L. SeixasNatália L. Seixas
Natália L. Seixas
CACarlos A.L. Antunes
Carlos A.L. Antunes
Maria Graça CamposMaria Graça Campos
Maria Graça Campos
VPVanessa Paula
Vanessa Paula
LELetícia M. Estevinho
Letícia M. Estevinho

20 October 2024 in Processes
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VPVanessa Paula
Vanessa Paula
MDMiguel Luís Sousa Dias
Miguel Luís Sousa Dias
Natália L. SeixasNatália L. Seixas
Natália L. Seixas
PFPatricia Combarros Fuertes
Patricia Combarros Fuertes
Leticia M. EstevinhoLeticia M. Estevinho
Leticia M. Estevinho
Luís G DiasLuís G Dias
Luís G Dias
The analytical results from a study of 16 honey samples (extra white to dark honey color range) of phenolic compounds obtained using the single UV spectrum methodology and classical spectrophotometric methods (Folin–Ciocalteu and AlCl3 methods) are presented. The first method quantified all classes of phenolic compounds in honey’s SPE-C18 extract: the total hydroxybenzoic acid content (concentrations between 0.37 ± 0.05 and 4.46 ± 0.37 mg of gallic acid/g of honey), total hydroxycinnamic acid content (0.13 ± 0.03 and 2.76 ± 0.13 mg of ferulic acid/g of honey), and total flavonoid content (0.15 ± 0.03 and 1.63 ± 0.17 mg of quercetin/g of honey). The total phenolic contents were, on average, 1.86 ± 0.72 and 1.78 ± 0.79 times higher than the results obtained for raw honey and the SPE-C18 extract, respectively, using the classical Folin–Ciocalteu method. The total flavonoid contents, on average, were 6.02 ± 3.14 times larger and 0.66 ± 0.33 times smaller than the results obtained using the classical AlCl3 method for raw honey and SPE-C18 extract, respectively.

8 February 2025 in Applied Sciences
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Sandra Sofia Quinteiro RodriguesSandra Sofia Quinteiro Rodrigues
Sandra Sofia Quinteiro Rodrigues
Ana LeiteAna Leite
Ana Leite
Lia Inês VasconcelosLia Inês Vasconcelos
Lia Inês Vasconcelos
EPEtelvina Pereira
Etelvina Pereira
Natália L. SeixasNatália L. Seixas
Natália L. Seixas
Alfredo TeixeiraAlfredo Teixeira
Alfredo Teixeira
This study aims to explore the effect of using black pepper essential oil (BPEO) to produce a healthier chicken pâté. Four different formulations were produced: a control formulation without back pepper and three with increasing BPEO contents. To test the effect of using BPEO, physiochemical analyses were performed at two different moments, 8 and 21 days after production. Microbiological analyses were performed 2, 9, 16, and 23 days after production. Sensory analysis to evaluate the pleasantness of the pâtés to consumers was performed 21 days after production. Finally, total phenol and flavonoid content and antioxidant activity were evaluated. Results show no significant physicochemical differences. Pâtés with no BPEO or black garlic were the most pleasant, but 0.3 or 0.5% of BPEO were not significantly less appreciated, while 1% of the EO caused a decrease in taste and global appreciation. The higher the BPEO content, the higher the phenol content, antioxidant (with an increase from 1.58 to 2.27 mg eq. Fe II/g of sample, in the Control at T23 and V3 at T23, respectively), and microbial activity (with total mesophiles count reduction from 5.91 to 5.21 log CFU/g sample in V3 from T9 to T16). The use of 1% of BPEO showed a significant effect on the reduction in mesophile counts for at least two weeks. These results highlight the potential for optimizing BPEO or black garlic content to ensure both consumer acceptance and enhanced functional properties. While further analysis will help pinpoint the best formulation, the current findings are a promising step towards achieving an optimal balance.

20 February 2025 in Foods
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Natália L. SeixasNatália L. Seixas
Natália L. Seixas
VPVanessa Paula
Vanessa Paula
TDTeresa Dias
Teresa Dias
Luís G DiasLuís G Dias
Luís G Dias
Leticia M. EstevinhoLeticia M. Estevinho
Leticia M. Estevinho
Elderberries, known for their antioxidant, anti-inflammatory, and antiviral properties, have traditionally been used to prevent and treat infections and boost the immune system. By increasing the quantity and quality of certain compounds, fermentation can potentially make them more effective as food additives. The aim of this study was to evaluate the effect of incorporating fermented elderberries on the bioactivity and shelf life of a traditional bread. The elderberry fermentation process was optimised using Saccharomyces cerevisiae, guided by a Plackett–Burman experimental design. The aim was to assess the impact of incorporating fermented elderberries into bread on its bioactive properties and shelf life. The fermentation of the elderberries was found to enhance their bioactive compounds and antioxidant activity. The total phenolic content ranged from 8.63 to 20.56 mg GAE/g (in samples without and with 2% extract, respectively). The antioxidant capacity, measured using the FRAP method, also showed a significant increase with the addition of the extract (from 9.16 to 26.66 mg Fe (II) E/g of the sample). Furthermore, bread enriched with fermented elderberry extracts demonstrated an extended shelf life during the study period.

15 November 2023 in Microorganisms
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SCSónia Coutinho
Sónia Coutinho
VMVanessa Matos
Vanessa Matos
Natália L. SeixasNatália L. Seixas
Natália L. Seixas
Hellen Freire RodriguesHellen Freire Rodrigues
Hellen Freire Rodrigues
VPVanessa Paula
Vanessa Paula
Leticia M. EstevinhoLeticia M. Estevinho
Leticia M. Estevinho
Geopropolis has been used in traditional medicine for centuries. In this study, the botanical origin, physicochemical profile, and biological activities of geopropolis from Melipona scutellaris harvested during rainy and dry seasons were investigated. Palynological analysis identified over 50 pollen types, with Schinus terebinthifolius and Cecropia being the predominant types. The analytical results were in line with those reported in the literature. Rainy-season geopropolis exhibited higher total phenol and flavonoid content (determined using High Performance Liquid Chromatography—25.13% and 3.92%, respectively) compared to the dry season (19.30% and 2.09%); the major peaks (naringin, gallic acid, and catechin) were similar among samples. Antioxidant capacity was assessed via DPPH, reducing power, and β-carotene/linoleic acid discoloration assays. Rainy-season samples displayed superior antioxidant activity across methods. Antimicrobial effects were determined using microdilution, while the impact on the cholinesterase enzyme was quantified using 5-thio-2-nitrobenzoic acid accumulation. Anti-inflammatory and antimutagenic activities were assessed through hyaluronidase enzyme inhibition and by utilizing Saccharomyces cerevisiae ATCC-20113 cells. Both samples exhibited anti-inflammatory and antimutagenic properties. Moreover, a significant inhibition of acetylcholinesterase was observed, with IC50 values of 0.35 µg/mL during the rainy season and 0.28 µg/mL during the dry season. Additionally, the geopropolis displayed antimicrobial activity, particularly against Staphylococcus aureus. These findings suggest the therapeutic potential of M. scutellaris geopropolis in the context of inflammatory, oxidative, and infectious diseases.