Water Extraction Kinetics of Bioactive Compounds of Fucus vesiculosus

Abstract

Brown macroalgae, particularly those from Fucus genus, are a rich and balanced source of bioactive nutrients and phytochemicals, such as dietary fibres (fucoidans, laminarins, and/or alginates), phlorotannins, and fucoxanthin, and some minerals, such as iodine, which have been demonstrated to possess numerous health-promoting properties. In fact, aqueous extracts of Fucus vesiculosus have been used as food supplements due to its rich content in bioactive compounds, though no study has been published on the optimization of this operation. Therefore, this study aimed to evaluate the impact of different extraction temperatures (25 °C, 50 °C, 75 °C, 100 °C, and 120 °C) and times (5 min, 1 h, 2 h, and 4 h) on the recovery of those bioactive compounds. The temperature was observed to positively influence the extraction of crude mass and of fucose polysaccharides only at 75 °C and above, and of iodine extraction at 50 °C and above. At these temperatures, time also showed to increase yields. Yields of crude extract, fucose, and iodine were successfully mathematically modelled with a power law, and its maximum yields were obtained at the highest temperature studied (120 °C) and longest extraction time (4 h). Iodine yield at these conditions provided extracts with relevant content to contribute to the recommended daily ingestion. Phlorotannins were significantly recovered at 120 °C though evidence of degradation was observed during time.

Multi-Step Subcritical Water Extracts of Fucus vesiculosus L. and Codium tomentosum Stackhouse: Composition, Health-Benefits and Safety

“…A similar trend was obtained for C. tomentosum, with the highest iodine content obtained for E1 fraction (42.0 µg/g) and the lowest for E4 fraction (0.511 µg/g). These results suggest that iodine appears to be present mainly as inorganic iodine, readily extractable with water [75], so that the first extraction step at lower temperature (90 • C) is the one with the highest yield. The high values for F. vesiculosus when compared to C. tomentosum are related to the ability of Fucus species to accumulate iodine, with Fucus species showing iodine levels as high as 500 mg/g dw [76] and Codium species values between 75.4 to 475.0 µg/g dw [39], which is in agreement with the values found in this study.…”

“…The levels of iodine and arsenic are presented in Table 3. F. vesiculosus showed a higher content of iodine in E1 fraction (90 • C), with 14.6 mg/g dw, decreasing throughout the extraction steps and consequently with the increasing of temperature (from 90 in E1 to 250 • C in E4), with the lowest values found in E4 fraction, with 1.25 mg/g at 250 • C. Ferreira et al [75] also evaluated the effect of different extraction temperatures (25, 50, 75, 100, and 120 • C) and extraction times (5 min, 1 h, 2 h, and 4 h) on the recovery of bioactive compounds, including iodine from F. vesiculosus. These authors reported that for temperatures between 50 and 120 • C, the amount of iodine extracted from F. vesiculosus increased with the time, with the highest value (0.4903 mg/g dw) obtained at 120 • C/4 h. In the present study, the E1 fraction was the one with the highest iodine content.…”

Fucoidan Characterization: Determination of Purity and Physicochemical and Chemical Properties

“…The total phenolic content can be quantified using the Folin–Ciocalteu method, especially for crude fucoidan products [ 113 , 114 ]. Additionally, the 2,4-dimethoxybenzaldehyde (DMBA) assay may be applied for phlorotannin content [ 115 ]. The Folin–Ciocalteu method is similar to the Folin–phenol applied for protein determination; however, the absorbance is recorded at 620 nm [ 114 ].…”

Fucoidans: Downstream Processes and Recent Applications

“…Novel techniques, either in cultivation or downstream processes, have been established, increasing the global production yields and reducing ecological and economic problems. A new advance toward achieving such goals was established by optimization of water extraction via measurement of kinetic parameters [205]. In addition to this, it is expected that most future trends in marine biotechnology research will focus on the cell wall and extracellular matrix components of brown algae, including fucoidans' biosynthetic genes and production regulators [23, 53,63,[206][207][208].…”