Browsing by Author "Valente, S."
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- Biochemical composition, nutritional value, and antioxidant properties of seven seaweed species from the Madeira ArchipelagoPublication . Nunes, N.; Ferraz, S.; Valente, S.; Barreto, Maria Carmo; Carvalho, M. A. A. Pinheiro deBiochemical composition and antioxidant activity were assessed in seven seaweeds from Madeira Archipelago, namely, the chlorophyte (Ulva lactuca), the rhodophytes (Asparagopsis taxiformis, Chondrus crispus, Galaxaura rugosa, Grateloupia lanceola and Nemalion elminthoides), and the phaeophyte (Zonaria tournefortii). Seaweed mineral content varied from 16.60 to 84.16 g (100 g)-1 dry weight (dw). Organic matter, composed by fiber and matrix polysaccharides (8.33 to 54.04 g (100 g)-1 dw), starch (1.95 to 25.41 g (100 g)-1 dw), protein (2.80 to 17.55 g (100 g)-1 dw), and fat (1.46 to 12.04 g (100 g)-1 dw), was also determined. Asparagopsis taxiformis was found to have substantial quantities of protein, fat, fiber, and matricial polysaccharides, compared to the other analyzed seaweeds. Analysis of antioxidant components included the measurement of chlorophyll a (28.81 to 244.3 g (100 g)-1 dw), total carotenoids (0 to 297.8 g (100 g)-1 dw), total phenolic compounds (0 to 2154 mg GAE (100 g)-1 dw), and total flavonols (7.27 to 604.8 mg QE (100 g)-1 dw). Zonaria tournefortii was found to possess the highest contents of chlorophyll a, total carotenoids, total phenolic content (TPC), and antioxidant activity, determined through ferric reduction antioxidant potential (FRAP), ferrous ion chelating (FIC), free radical-scavenging assay (FRSA), and β-carotene bleaching (β-CB). Statistical analysis showed 38 significant correlations between various biochemical and antioxidant parameters or activity and determined that fat content showed the highest number of correlations. Overall, this study gives a better understanding of Madeira autochthonous seaweeds in their potential of being introduced as a raw material for nutrient supplementation in various food products or to produce functional foods using seaweed natural properties.
- Constructing ethanol-derived bioactive extracts using the brown seaweed Zonaria tournefortii (J.V.Lamouroux) Montagne performed with Timatic extractor by means of response surface methodology (RSM)Publication . Nunes, N.; Valente, S.; Ferraz, S.; Barreto, Maria Carmo; Carvalho, M.A.A. Pinheiro deUnderstanding the biochemical and antioxidant composition and capacity of a target biomass is the first step to its selectivity as functional food which can enhance the ability to promote health by reducing the risk of chronic diseases. The main purpose of this work was to employ response surface methodology (RSM) to determine the effect of the independent variables, % of ethanol (50–96%), time of sonication (0–20 min), and number of extraction cycles (6–18 cycles) in the primary extract of brown seaweed Zonaria tournefortii, studying the yield variation of some bioactive compounds, assessing the potential of these bioextracts to integrate as a natural additives or supplements in the functional food industry. The extractions were performed employing “Green Chemistry” techniques executed with the Timatic extractor, which applied pressurized ethanol solution at a maximum pressure of 8.5 bar through milled dehydrated biomass in the extraction vessel. Several parameters were assessed in the primary bioactive extract which included extract yield (11.56–28.49 g (100 g)−1 dw), total chlorophyll content (0.14–1.42 g (100 g)−1 dw), total carotenoid content (0.35–0.80 g (100 g)−1 dw), total fucoxanthin content (0.04–0.13 g (100 g)−1 dw), total phenolic content (3.58–5.84 g (100 g)−1 dw), total flavonoid content (0.22–4.70 g (100 g)−1 dw), DPPH (56.05–76.45%), and reducing activity (3.83–6.04 g (100 g)−1 dw). A second objective was to determine the suitability of the residue for subsequent extraction of valuable compounds such as fucoidan (4.87 to 6.59 g (100 g)−1 dw) and cellulose (18.88 to 20.27 g (100 g)−1 dw), implementing the first step to a biorefinery strategy, using a cascade approach.
- Nutraceutical potential of Asparagopsis taxiformis (Delile) Trevisan extracts and assessment of a downstream purification strategyPublication . Nunes, N.; Valente, S.; Ferraz, S.; Barreto, Maria Carmo; Carvalho, M. A. A. Pinheiro deThe main goal of the present work was to determine the nutraceutical potential of Asparagopsis taxiformis D. extracts from Madeira Archipelago south coast. Extraction methodologies consisted either/or in 72 hours stirring, at room temperature (M1), or 6 cycles of Soxhlet extraction (M2), both with re-extraction. Solvents used were distilled water, ethanol, methanol and ethyl acetate. M1 allowed to obtain the highest values for extraction yield (31.65 g.100g 1 dw) using water, whereas iodine content (3.37 g.100g 1 dw), TPC (1.71 g GAE.100g 1 dw) and chlorophyll a (45.96 mg.100g 1 dw) were obtained using ethanol, and TCC (36.23 mg.100g 1 dw) with methanol. Extracts that showed higher reduction activity in M1 were derived from ethanol extraction (1,908 mg AAE.100g 1 dw). Water and ethanol were the best solvents for higher DPPH scavenging activity in M2, both with same result (IC50 1.37 mg.mL 1 ). The lowest value of IC50 for chelating activity (1.57 mg.mL 1 ) was determined in M1, using ethyl acetate. The remaining residue was used to obtain other products, i.e. lipid extraction (M1, 2.05 g.100g 1 dw), carrageenans (M2, 21.18 g.100g 1 dw) and cellulose (M1, 23.81 g.100g 1 dw) with subsequent FTIR ATR analysis. Our results show that A. taxiformis is a valuable source of bioactive compounds. The M1 extraction methodology using ethanol is the most effective solvent to produce an iodine rich bioactive extract with potential of being used as a nutraceutical supplement. Also, we have demonstrated a possible downstream strategy that could be implemented for multiple compound extraction from A. taxiformis residue. This has a vital importance for future feasibility, when using this biomass as an industrial feedstock for multiple products production. Statistical analysis, using SPSS 24.0, was also performed and important correlations were found between assays and methods.
- Nutraceutical potential of Asparagopsis taxiformis (Delile) Trevisan extracts and assessment of a downstream purification strategyPublication . Nunes, Nuno; Valente, S.; Ferraz, Sónia; Barreto, Maria Carmo; Carvalho, M .A. A. Pinheiro deThe main goal of the present work was to determine the nutraceutical potential of Asparagopsis taxiformis D. extracts from Madeira Archipelago south coast. Extraction methodologies consisted either/or in 72 hours stirring, at room temperature (M1), or 6 cycles of Soxhlet extraction (M2), both with re-extraction. Solvents used were distilled water, ethanol, methanol and ethyl acetate. M1 allowed to obtain the highest values for extraction yield (31.65 g.100g 1 dw) using water, whereas iodine content (3.37 g.100g 1 dw), TPC (1.71 g GAE.100g 1 dw) and chlorophyll a (45.96 mg.100g 1 dw) were obtained using ethanol, and TCC (36.23 mg.100g 1 dw) with methanol. Extracts that showed higher reduction activity in M1 were derived from ethanol extraction (1,908 mg AAE.100g 1 dw). Water and ethanol were the best solvents for higher DPPH scavenging activity in M2, both with same result (IC50 1.37 mg.mL 1 ). The lowest value of IC50 for chelating activity (1.57 mg.mL 1 ) was determined in M1, using ethyl acetate. The remaining residue was used to obtain other products, i.e. lipid extraction (M1, 2.05 g.100g 1 dw), carrageenans (M2, 21.18 g.100g 1 dw) and cellulose (M1, 23.81 g.100g 1 dw) with subsequent FTIR ATR analysis. Our results show that A. taxiformis is a valuable source of bioactive compounds. The M1 extraction methodology using ethanol is the most effective solvent to produce an iodine rich bioactive extract with potential of being used as a nutraceutical supplement. Also, we have demonstrated a possible downstream strategy that could be implemented for multiple compound extraction from A. taxiformis residue. This has a vital importance for future feasibility, when using this biomass as an industrial feedstock for multiple products production. Statistical analysis, using SPSS 24.0, was also performed and important correlations were found between assays and methods.
- Nutraceutical potential of Asparagopsis taxiformis (Delile) Trevisan extracts and assessment of a downstream purification strategyPublication . Nunes, N.; Valente, S.; Ferraz, S.; Barreto, Maria Carmo; Carvalho, M. A. A. Pinheiro deThe main goal of the present work was to determine the nutraceutical potential of Asparagopsis taxiformis D. extracts from Madeira Archipelago south coast. Extraction methodologies consisted either/or in 72 hours stirring, at room temperature (M1), or 6 cycles of Soxhlet extraction (M2), both with re-extraction. Solvents used were distilled water, ethanol, methanol and ethyl acetate. M1 allowed to obtain the highest values for extraction yield (31.65 g.100g 1 dw) using water, whereas iodine content (3.37 g.100g 1 dw), TPC (1.71 g GAE.100g 1 dw) and chlorophyll a (45.96 mg.100g 1 dw) were obtained using ethanol, and TCC (36.23 mg.100g 1 dw) with methanol. Extracts that showed higher reduction activity in M1 were derived from ethanol extraction (1,908 mg AAE.100g 1 dw). Water and ethanol were the best solvents for higher DPPH scavenging activity in M2, both with same result (IC50 1.37 mg.mL 1 ). The lowest value of IC50 for chelating activity (1.57 mg.mL 1 ) was determined in M1, using ethyl acetate. The remaining residue was used to obtain other products, i.e. lipid extraction (M1, 2.05 g.100g 1 dw), carrageenans (M2, 21.18 g.100g 1 dw) and cellulose (M1, 23.81 g.100g 1 dw) with subsequent FTIR ATR analysis. Our results show that A. taxiformis is a valuable source of bioactive compounds. The M1 extraction methodology using ethanol is the most effective solvent to produce an iodine rich bioactive extract with potential of being used as a nutraceutical supplement. Also, we have demonstrated a possible downstream strategy that could be implemented for multiple compound extraction from A. taxiformis residue. This has a vital importance for future feasibility, when using this biomass as an industrial feedstock for multiple products production. Statistical analysis, using SPSS 24.0, was also performed and important correlations were found between assays and methods.
- Validation of a spectrophotometric methodology for a rapid iodine analysis in algae and seaweed castsPublication . Nunes, N.; Valente, S.; Ferraz, S.; Barreto, Maria Carmo; Carvalho, M.A.A. Pinheiro deIodine plays an important role in human metabolism and its deficiency is particularly harmful in pregnancy and childhood. It remains a major public health concern in many countries, especially in Portugal. The main purpose of this work was to develop a validated spectrophotometric analysis for a fast and reliable iodine quantification in algal samples. Absorbance was determined at 410 nm demonstrating a good linearity (R2 ≈ 1.0) in the range of 0–0.06 mg I/100 g. LOD and LOQ were 1.7 × 10−3 and 5.0 × 10−3 mg I/100 g, respectively. Accuracy was determined using recovery and varied between 101 and 118%. For precision analysis, an intra-day test performance (RSD = 8.7%) and a repeatability assay (RSD = 3.8%) were performed. Matrix effect assessment demonstrated that this had a negligible effect (3.2%) in the iodine quantification. The spectrophotometric method was externally validated, for iodine quantification in algal samples, by INSA certified laboratory. The correlation coefficient between external iodine quantification and our work was R2 ≈ 0.9, showing a good correlation. Applicability was assessed in 25 macroalgae species (5 green, 9 red and 11 brown), 12 seaweed casts, collected in Canary Islands and 1 microalga (Isochrysis galbana) provided by ITC (Instituto Tecnologico de Canarias).