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- Optimization of ultrasound-assisted extraction of bioactive compounds from Pelvetia canaliculata to sunflower oilPublication . Sousa, Gabriela; Trifunovska, Marija; Antunes, Madalena; Miranda, Isabel; Moldão-Martins, Margarida; Alves, Vitor D.; Vidrih, Rajko; Lopes, Paula Allen; Aparicio, Luis; Neves, Marta; Tecelão, Carla; Ferreira-Dias, SuzanaIn this study, Pelvetia canaliculata L. macroalga, collected from the Atlantic Portuguese coast, was used as a source of bioactive compounds, mostly antioxidants, to incorporate them in sunflower oil with the aim of increasing its biological value and oxidative stability. The lyophilized alga was added to the oil, and ultrasound‐assisted extraction (UAE) was performed. Algae concentration and UAE time varied following a central composite rotatable design (CCRD) to optimize extraction conditions. The following parameters were analyzed in the oils: oxidation products, acidity, color, chlorophyll pigments, carotenoids, flavonoids, total phenolic content, antioxidant activity by DPPH (2,2‐diphenyl‐1‐picrylhydrazyl) and FRAP (ferric reducing antioxidant power) assays, and sensory analysis. Extraction conditions did not affect the acidity and the amount of oxidation products in the oil. Chlorophylls and carotenoid contents increased with algae concentration, while flavonoid extraction did not depend on algae content or UAE time. Total phenolics in the oil were highly related only to FRAP antioxidant activity. Storage experiments of supplemented oil (12.5% algae; 20 min UAE) were carried out under accelerated oxidation conditions at 60 °C/12 days. Antioxidant activity (FRAP) of supplemented oil was 6‐fold higher than the value of non‐supplemented oil. Final samples retained 40% of their initial antioxidant activity. The presence of algae extracts contributed to the increased oxidative stability of sunflower oil.
- Physicochemical and nutritional characterization of the leaves, flowers and fruits of Chorão da praia (Carpobrotus edulis) from Portuguese west shoresPublication . Neves, Marta; Antunes, Madalena; Azevedo, Zélia M.; Freitas, Victor; Rocha, João M.; Tecelão, CarlaLeaves, flowers and fruits from the edible halophyte Chorão da praia (Carpobrotus edulis), harvested in Portuguese west shores, were characterized regarding their proximate composition, phenolic compounds and antioxidant activity. Flowers and leaves had similar protein content (5.42±0.15 and 5.22 ±0.13 % DW, respectively), being higher than fruits (4.67±0.22 %). No significant differences were observed in the lipid fraction, ranging from 1.70 ± 0.12 in flowers to 1.90 ± 0.16 % DW in leaves. Fruits presented the highest value of total carbohydrates (71.5±1.2 % DW), whereas ash was more abundant in leaves (32.00 ± 0.35 % DW) that also showed the highest chlorophylls content, comprising 52.0±7.2 μg/g chl a and 26.2±8.2 μg/g chl b. Similar levels of total carotenoids were observed in leaves and flowers (5.7±1.6 and 4.6±1.4 μg/g DW, respectively), being significantly higher than fruits (2.8±0.2 μg/g DW). Aqueous-ethanolic (1:1, v/v) extract of flowers exhibited the highest total phenolic content (299±8 μg/mg of gallic acid equivalents), by the Folin–Ciocalteu method, as well as the strongest antioxidant activity (3.25±0.21 and 2.38±0.07 μmol/mg of trolox equivalents by the DPPH and FRAP methods, respectively), followed by leaves (1.68±0.16 and 1.36±0.14 μmol/mg) and fruits (0.58±0.13 and 0.71±0.03 μmol/mg). Bulk polyphenol extracts were further purified through Solid-Phase Extraction (SPE), using C18 reversed-phase sorbent Oasis® Prime HLB Extraction cartridges. Polyphenols in purified extracts were initially analyzed by RP-HPLC-DAD and a separation chromatographic method was developed and optimized. The optimal elution program was further used for the separation and identification of polyphenols via RP-HPLC-ESI-MS/MS. Mass spectra unfolded the complete or partial separation of molecular species of polyphenols. Moreover, mass and tandem mass spectra revealed that the most abundant species in all extracts were glycosylated and/or acetylated O-Methyl flavonols. It was observed compounds mainly derived from syringetin and laricitrin. Each of these two aglycones revealed two major compounds: two [MH]- ions with m/z 653 (syringetine derivatives) and two [M-H]- ions with m/z 639 (laricitrin derivatives). In both cases, the MS2 data of the [M-H]- ions showed high intensity fragment ions with m/z 345 and 331, respectively, corresponding to the loose of a glucosyl-alfa-araninofuranoside or an acetylated glucoside [M-308]. Moreover, the MS3 data of the two most intense fragment resulted in successive loss of methyl groups with the first one presenting the highest intensity. Regarding the profile in polyphenols, when comparing leaves, flowers and fruits, one concluded that there are clearly differences in the relative amount of these polyphenols being flowers richer in the syringetin derivatives.
- Estudo bioquímico e fisiológico aplicado à macroalga Saccorhiza polyschidesPublication . Antunes, Madalena Sofia Fernandes; Gonçalves, José Carlos Dias Duarte; Debiasi, Clayton; Mouga, Teresa Margarida Lopes da Silva; Afonso, Clélia Paulete Correia NevesAs macroalgas marinhas são recursos abundantes muitas vezes subvalorizados. Tendo em conta a vasta costa portuguesa, as macroalgas são um recurso de fácil acesso e promissor no que respeita ao seu conteúdo em compostos bioativos. A cultura de células e tecidos vegetais é um ramo da biotecnologia que visa a propagação de espécies vegetais, inicialmente in vitro, em meio nutritivo e em condições asséticas. O meio de cultura para a multiplicação de espécies vegetais tem de fornecer o conteúdo mineral, uma fonte de carbono, vitaminas e, frequentemente, reguladores de crescimento. Dentro dos reguladores de crescimento mais conhecidos encontram-se as auxinas, citocininas, giberelinas e ácido abscísico, as quais são frequentemente obtidas sinteticamente, e aplicadas neste tipo de cultura. A Saccorhiza polyschides, uma macroalga abundante nos meses de verão na costa de Peniche, é regularmente associada à agricultura como um fertilizante eficaz. Desta forma, a sua associação a reguladores de crescimento vegetais torna-se inevitável. Sendo assim, o principal objetivo deste trabalho foi extrair reguladores de crescimento vegetais desta alga, de modo a substituir as commumente utilizadas em cultura de células e tecidos vegetais. Para tal, analisou-se o conteúdo em macro e microelementos da alga em estudo e avaliou-se um extrato etanólico no que respeita à sua capacidade antioxidante e reguladora de crescimento. Posteriormente, recorreu-se a técnicas cromatográficas para a extração, separação e purificação de compostos de natureza auxínica ou citocinínica. Verificou-se que a S. polyschides possui um conteúdo mineral maioritariamente composto por potássio e sódio, respetivamente aos macroelementos, e por boro e ferro, no que respeita aos oligonutrientes. O extrato etanólico demonstrou possuir um conteúdo total em fenóis de 400 ± 13 µg EAG/g PS. No entanto, este extrato não mostrou eficácia na substituição de citocininas durante a micropropagação de castanheiro (Castanea sp.) nas concentrações testadas, verificando-se ainda uma diminuição do vigor e um aumento da oxidação e vitrificação dos explantes com o aumento da concentração do extrato adicionado ao meio de cultura. Ainda assim, foi possível verificar a presença de citocininas no extrato algal, quando aplicadas em meio de cultura com a finalidade de produzir biomassa de callus de Glycine max. Não se observou a presença de auxinas após a tentativa de extração e purificação cromatográfica deste regulador de crescimento da alga.
- Proximate composition and fatty acid profile of Gilthead seabream (Sparus aurata) fed with Pelvetia canaliculata supplemented diets: An insight towards the valorization of seaweed biomassPublication . Antunes, Madalena; Neves, Marta; Pires, Damiana; Passos, Ricardo; Carmo, Beatriz do; Tchobanov, Carolina F.; Forte, Sara; Vaz, Mariana; Baptista, Teresa; Tecelão, CarlaSeaweeds are a sustainable source of protein and lipids that may be used to replace fish by-products in aquaculture feed. This study aimed at using the macroalgae Pelvetia canaliculata as an ingredient in gilthead seabream (Sparus aurata) feed, either as freeze-dried powder or as algae residue (waste) that was obtained after the supplementation of sunflower oil. The formulated diets and the fish muscle were analyzed concerning the proximate composition and the fatty acid profile. The health lipid indices hypocholesterolemic/ hypercholesterolemic (h/H), atherogenic (AI), thrombogenic (TI), as well as n-3/n-6 and polyunsaturated fatty acid/saturated fatty acid (PUFA/SFA) ratios were calculated. Additionally, the peroxidizability index (PI) was determined. No differences were observed in the proximate composition of fish muscle regardless of the diet used. Fish fed a diet supplemented with 10% of algae waste (W10) stand out for the highest content in oleic acid (C18:1 n-9), and the lowest in both linoleic (C18:2 n-6) and palmitic (C16:0) fatty acids. All fish samples showed values of health lipid indices within the limits recommend for a nutritional balanced diet. These results highlight that fish fed diets supplemented with P. canaliculata are sources of healthy lipids that might be consumed on a regular basis to prevent cardiovascular diseases.
- Nannochloropsis oceanica as a sustainable source of n-3 polyunsaturated fatty acids for enrichment of hen eggsPublication . Neves, Marta; Ferreira, Ana; Antunes, Madalena; Silva, Joana; Mendes, Susana; Gil, Maria M.; Tecelão, CarlaThis study aimed to evaluate the potential of the marine microalgae Nannochloropsis oceanica as a sustainable source of n-3 polyunsaturated fatty acids (n-3 PUFA) for hen eggs enrichment. During 4 weeks, hens were fed with 3% (w/w) of Nannochloropsis oceanica supplemented diet. Throughout the assay, eggs were analyzed according to several nutritional and physical parameters, namely: (i) protein, fat, and ash content; (ii) fatty acid profile; (iii) thickness and colour of the shell; (iv) total egg weight; (v) protein quality (HU) and (vi) yolk colour. A remarkable increase in eicosapentaenoic (EPA), from 2.1 ± 0.1 to 5.2 ± 1.2 mg/100 g, and docosahexaenoic (DHA), from 50.3 ± 4.0 to 105 ± 18 mg/100 g, fatty acids was observed. Yolk colour also changed significantly according to the La Roche scale, from 9.6 ± 0.8 to 11.4 ± 0.8 (more orange). Feed supplementation did not lead to changes in the remaining analyzed parameters. A shelf life study, carried out for 28 days at room temperature, showed a decrease in eggs protein quality. In conclusion, eggs from hens fed with Nannochloropsis oceanica had a yolk colour more appealing to consumers and higher levels of EPA and DHA, allowing its classification as high in n-3 PUFA (CE nº 1924/2006).
- Physicochemical and nutritional profile of leaves, flowers, and fruits of the edible halophyte chorão-da-praia (Carpobrotus edulis) on Portuguese west shoresPublication . Neves, Marta; Antunes, Madalena; Fernandes, Wilson; Azevedo, Zélia M.; Freitas, Victor; Rocha, João M.; Tecelão, Carla; Campos, Maria J.Leaves, flowers and fruits from the edible halophyte chorão-da-praia (Carpobrotus edulis), harvested in the Portuguese western sea shores, were characterized regarding their proximate composition, fatty acid profile, pigments, phenolic compounds, antioxidant and antimicrobial activities. Fruits had the highest amount of carbohydrates (70.2 ± 1.6%) and the lowest of protein (4.67 ± 0.22%) and ash (22.0 ± 1.0%) contents. No significant differences were observed in the lipid fraction. Leaves were mainly constituted by saturated (52.6 ± 1.3%) fatty acids (FA), whereas fruits showed the highest amount of polyunsaturated FA (48.6 ± 3.1%). Chlorophylls and carotenoids were more abundant in leaves. Aqueous-ethanolic (1:1, v/v) extract of flowers exhibited the highest phenolic content (299 ± 8 μg/mg of gallic acid equivalents), by the Folin–Ciocalteu methodology, as well as the strongest antioxidant activity (IC50 = 11.83 ± 1.0 μg/mL and 7.82 ± 0.24 μmol/mg of ascorbic acid equivalents by the DPPH and FRAP methods, respectively). Also, flowers extract showed the most pronounced antimicrobial activity by the microtiter broth dilution method. Mass and tandem mass spectra revealed that the most abundant species in all extracts were glycosylated and/or acetylated O-Methyl flavonols, mainly derived from syringetin and laricitrin. Nuclear magnetic resonance was also employed for complementary confirmation of the syringetin moieties. Regarding the profile in polyphenols, when comparing leaves, flowers and fruits, one concluded that there were clearly differences in the relative amount of these polyphenols, being flowers richer in the syringetin derivatives. In conclusion, this edible plant, classified as an invasive species of the Portuguese coast, highlights for its richness in bioactive compounds with potential application in the food industry.
- Pelvetia canaliculata as an aquafeed supplement for gilthead seabream Sparus aurata: A biorefinery approach for seaweed biomass valorisationPublication . Pires, Damiana; Passos, Ricardo; Carmo, Beatriz do; Tchobanov, Carolina F.; Forte, Sara; Vaz, Mariana; Antunes, Madalena; Tecelão, Carla; Baptista, TeresaFor sustainable and economically viable aquaculture, it is necessary to search for alternative sources of aquafeeds. Algae have been studied because of their bioactive compounds with several activities such as antioxidants. The direct incorporation of the macroalgae Pelvetia canaliculata in sunflower oil to increase oxidative stability and biological value results in waste with high nutritional value that may be used as an ingredient in aquaculture feed. This study aimed to evaluate the effect of incorporating algae powder (PEL 1%, PEL 10%) and algae waste obtained after sunflower oil supplementation (WO 1%, WO 10%) in aquafeeds for gilthead seabream. We studied the growth performance, haematological profile, oxidative stress and metabolic parameters, and intestine histomorphology. Experimental diets did not influence growth performance or somatic indexes, and barely affected the haematological profile. Catalase showed higher activity in seabream fed with PEL10 than with control diet. Total glutathione had a higher activity in fish fed with both WO diets. Plasmatic levels of cholesterol were higher in PEL1 and WO10. Triglyceride levels were higher in WO1 and total lipids were higher in both WO diets. The histomorphology of the intestine was slightly modulated by experimental diets but was not affected negatively. In general, supplementation with Pelvetia powder and algal waste oil may be used as an aquafeed for gilthead seabream according to the results obtained for growth, some haematological parameters, catalase and total glutathione, intestinal villi length, and the number of total and acid goblet cells.
- Seaweed Pelvetia canaliculata as a Source of Bioactive Compounds for Application in Fried Pre-Coated Mackerel (Scomber scombrus) Fillets: A Functional Food ApproachPublication . Freire, Catarina D.; Antunes, Madalena; Silva, Susana F. J.; Neves, Marta; Tecelão, CarlaFatty fish, such as mackerel (Scomber scombrus), are recommended as part of a healthy diet, providing essential fatty acids (FA). Fried fish is appreciated for its attributes, including a crispy texture, golden crust, and pleasant taste. However, frying increases the fat content and the caloric value of food. This study evaluated the use of pre-frying edible coatings on mackerel fillets aiming to: (i) reduce oil absorption, (ii) minimize water loss, preserving fish succulence, and (iii) prevent fat oxidation. For this purpose, alginate- and carrageenan-based coatings were supplemented with extracts of Pelvetia canaliculata (Pc), a seaweed with high potential as a source of bioactive compounds. The fried fillets were analysed for colour, texture, moisture, ash, lipid content, and FA profile. No significant differences were observed for colour and textural parameters. Fillets coated with Pc-supplemented carrageenan showed the highest moisture (an increase of 3%) and the lowest fat content (a decrease of 7,5%) compared to the control (fried uncoated fillets). Coated fillets also exhibited reduced saturated FA and increased monounsaturated FA. In general, linoleic acid (C18:2) decreased markedly, while the values for docosahexaenoic acid (C22:6, n-3) remained stable (11–12% of total FA). Moreover, the n3/n6 ratio and atherogenic indices (AI) were improved in the coated fillets.
- Nutritive Value and Bioactivities of a Halophyte Edible Plant: Crithmum maritimum L. (Sea Fennel)Publication . Correia, Iris; Antunes, Madalena; Tecelão, Carla; Neves, Marta; Pires, Cristiana L.; Cruz, Pedro F.; Peralta, Claúdia C.; Pereira, Cidália D.; Reboredo, Fernando; Moreno, Maria João; Brito, Rui M. M.; Vaz, Daniela C.; Campos, Maria; Rodrigues, Maria JorgeCrithmum maritimum L. (sea fennel), an edible xerophyte of coastal habitats, is considered an emerging cash crop for biosaline agriculture due to its salt-tolerance ability and potential applications in the agri-food sector. Here, the nutritional value and bioactive properties of sea fennel are described. Sea fennel leaves, flowers, and schizocarps are composed of carbohydrates (>65%) followed by ash, proteins, and lipids. Sea fennel’s salty, succulent leaves are a source of omega-6 and omega-3 polyunsaturated fatty acids, especially linoleic acid. Extracts obtained from flowers and fruits/schizocarps are rich in antioxidants and polyphenols and show antimicrobial activity against Staphylococcus aureus, Staphylococcus epidermis, Candida albicans, and Candida parapsilosis. Plant material is particularly rich in sodium (Na) but also in other nutritionally relevant minerals, such as calcium (Ca), chlorine (Cl), potassium (K), phosphorus (P), and sulfur (S), beyond presenting a potential prebiotic effect on Lactobacillus bulgaricus and being nontoxic to human intestinal epithelial Caco-2 model cells, up to 1.0% (w/v). Hence, the rational use of sea fennel can bring nutrients, aroma, and flavor to culinary dishes while balancing microbiomes and contributing to expanding the shelf life of food products.