2021
Gómez-Mascaraque, Laura G.; Martínez-Sanz, Marta; Martínez-López, Rosalia; Martínez-Abad, Antonio; Panikuttira, Bhavya; López-Rubio, Amparo; Tuohy, Maria G.; Hogan, Sean A.; Brodkorb, André
Characterization and gelling properties of a bioactive extract from Ascophyllum nodosum obtained using a chemical-free approach Artículo de revista
En: Current Research in Food Science, vol. 4, pp. 354-364, 2021, ISSN: 2665-9271.
Resumen | Enlaces | BibTeX | Etiquetas: Algae, Hydrogel, Polysaccharide, SAXS, Seaweed
@article{GOMEZMASCARAQUE2021354,
title = {Characterization and gelling properties of a bioactive extract from Ascophyllum nodosum obtained using a chemical-free approach},
author = {Laura G. Gómez-Mascaraque and Marta Martínez-Sanz and Rosalia Martínez-López and Antonio Martínez-Abad and Bhavya Panikuttira and Amparo López-Rubio and Maria G. Tuohy and Sean A. Hogan and André Brodkorb},
url = {https://www.sciencedirect.com/science/article/pii/S266592712100037X},
doi = {https://doi.org/10.1016/j.crfs.2021.05.005},
issn = {2665-9271},
year = {2021},
date = {2021-01-01},
journal = {Current Research in Food Science},
volume = {4},
pages = {354-364},
abstract = {The bioactivity and gelling properties of a carbohydrate-rich algal extract obtained from locally harvested Ascophyllum nodosum seaweed using a chemical-free approach were investigated for its potential interest in food applications. Physicochemical characterisation and compositional analysis of the extract, using FTIR, biochemical methods and monosaccharide analysis, confirmed the presence of alginates and fucoidans, although the main polysaccharide present in it was laminarin. Significant amounts of phenolic compounds (~9 mg phloroglucinol/100 mg sample) were also detected. As a result, the extract exhibited good antioxidant activity. It also showed promising prebiotic potential, promoting the growth of beneficial Lactobacillus sp. and Bifidobacteria sp. when compared with commercial prebiotics, but not that of pathogenic bacteria such as E. coli or P. aeruginosa. The gelling properties of the raw extract were explored to optimize hydrogel bead formation by external gelation in CaCl2 solutions. This was enhanced at neutral to alkaline pHs and high extract and CaCl2 concentrations. The mechanical strength, nano- and microstructure of the hydrogel beads prepared under optimised conditions were determined using compression tests, synchrotron small- and wide-angle X-ray scattering (SAXS/WAXS) and scanning electron microscopy (SEM). It was concluded that the raw algal extract at neutral pH had potential for use as a gelling agent, although further enrichment with alginate improved the mechanical properties of the obtained gels. The advantages and disadvantages of applying the non-purified algal extract in comparison with purified carbohydrates are discussed.},
keywords = {Algae, Hydrogel, Polysaccharide, SAXS, Seaweed},
pubstate = {published},
tppubtype = {article}
}
The bioactivity and gelling properties of a carbohydrate-rich algal extract obtained from locally harvested Ascophyllum nodosum seaweed using a chemical-free approach were investigated for its potential interest in food applications. Physicochemical characterisation and compositional analysis of the extract, using FTIR, biochemical methods and monosaccharide analysis, confirmed the presence of alginates and fucoidans, although the main polysaccharide present in it was laminarin. Significant amounts of phenolic compounds (~9 mg phloroglucinol/100 mg sample) were also detected. As a result, the extract exhibited good antioxidant activity. It also showed promising prebiotic potential, promoting the growth of beneficial Lactobacillus sp. and Bifidobacteria sp. when compared with commercial prebiotics, but not that of pathogenic bacteria such as E. coli or P. aeruginosa. The gelling properties of the raw extract were explored to optimize hydrogel bead formation by external gelation in CaCl2 solutions. This was enhanced at neutral to alkaline pHs and high extract and CaCl2 concentrations. The mechanical strength, nano- and microstructure of the hydrogel beads prepared under optimised conditions were determined using compression tests, synchrotron small- and wide-angle X-ray scattering (SAXS/WAXS) and scanning electron microscopy (SEM). It was concluded that the raw algal extract at neutral pH had potential for use as a gelling agent, although further enrichment with alginate improved the mechanical properties of the obtained gels. The advantages and disadvantages of applying the non-purified algal extract in comparison with purified carbohydrates are discussed.
2020
Fontes-Candia, Cynthia; Ström, Anna; Gómez-Mascaraque, Laura G.; López-Rubio, Amparo; Martínez-Sanz, Marta
Understanding nanostructural differences in hydrogels from commercial carrageenans: Combined small angle X-ray scattering and rheological studies Artículo de revista
En: Algal Research, vol. 47, pp. 101882, 2020, ISSN: 2211-9264.
Resumen | Enlaces | BibTeX | Etiquetas: Food texture, Gelation, Polysaccharide, Scattering, Seaweed
@article{FONTESCANDIA2020101882,
title = {Understanding nanostructural differences in hydrogels from commercial carrageenans: Combined small angle X-ray scattering and rheological studies},
author = {Cynthia Fontes-Candia and Anna Ström and Laura G. Gómez-Mascaraque and Amparo López-Rubio and Marta Martínez-Sanz},
url = {https://www.sciencedirect.com/science/article/pii/S2211926419309932},
doi = {https://doi.org/10.1016/j.algal.2020.101882},
issn = {2211-9264},
year = {2020},
date = {2020-01-01},
journal = {Algal Research},
volume = {47},
pages = {101882},
abstract = {Hydrogels from commercial carrageenans (κ-C, ι-C, λ↑-C (high viscosity) and λ↓-C (low viscosity)) were prepared with and without the addition of salts (KCl and CaCl2). FT-IR and 1H NMR characterization evidenced that while the κ-C and ι-C grades were relatively pure carrageenans, the two λ-C grades were λ-, κ-, θ- and μ-carrageenan hybrids. The effect of carrageenan and salt concentration on the hydrogel strength were evaluated through a response surface design and a detailed structural characterization was carried out by small angle X-ray scattering (SAXS) and rheology. The low amount of sulphate substitution in κ-C enabled intramolecular association, giving rise to strong hydrogels, even in the absence of salts. On the other hand, ι-C, λ↑-C and λ↓-C produced much weaker hydrogels and required the addition of salts to induce intramolecular association by ionic cross-linking. SAXS results suggested the formation of similar structures of double helices in κ-C and ι-C with the addition of salts; however, distinct network structures were attained. In the case of κ-C, a Gauss-Lorentz gel model was suitable to describe the hydrogel structure and the addition of K+ promoted the formation of more ordered and densely packed structures. On the other hand, larger but weaker aggregates, with marked periodicity, were observed in ι-C, with Ca2+ inducing the formation of more densely packed networks. The complex composition of the λ-C grades gave rise to more heterogeneous branched network structures, properly described by a correlation length model, where the gelation mechanism was mostly governed by the κ-carrageenan component.},
keywords = {Food texture, Gelation, Polysaccharide, Scattering, Seaweed},
pubstate = {published},
tppubtype = {article}
}
Hydrogels from commercial carrageenans (κ-C, ι-C, λ↑-C (high viscosity) and λ↓-C (low viscosity)) were prepared with and without the addition of salts (KCl and CaCl2). FT-IR and 1H NMR characterization evidenced that while the κ-C and ι-C grades were relatively pure carrageenans, the two λ-C grades were λ-, κ-, θ- and μ-carrageenan hybrids. The effect of carrageenan and salt concentration on the hydrogel strength were evaluated through a response surface design and a detailed structural characterization was carried out by small angle X-ray scattering (SAXS) and rheology. The low amount of sulphate substitution in κ-C enabled intramolecular association, giving rise to strong hydrogels, even in the absence of salts. On the other hand, ι-C, λ↑-C and λ↓-C produced much weaker hydrogels and required the addition of salts to induce intramolecular association by ionic cross-linking. SAXS results suggested the formation of similar structures of double helices in κ-C and ι-C with the addition of salts; however, distinct network structures were attained. In the case of κ-C, a Gauss-Lorentz gel model was suitable to describe the hydrogel structure and the addition of K+ promoted the formation of more ordered and densely packed structures. On the other hand, larger but weaker aggregates, with marked periodicity, were observed in ι-C, with Ca2+ inducing the formation of more densely packed networks. The complex composition of the λ-C grades gave rise to more heterogeneous branched network structures, properly described by a correlation length model, where the gelation mechanism was mostly governed by the κ-carrageenan component.
Fontes-Candia, Cynthia; Ström, Anna; Lopez-Sanchez, Patricia; López-Rubio, Amparo; Martínez-Sanz, Marta
Rheological and structural characterization of carrageenan emulsion gels Artículo de revista
En: Algal Research, vol. 47, pp. 101873, 2020, ISSN: 2211-9264.
Resumen | Enlaces | BibTeX | Etiquetas: Fat replacement, Gelation, Polysaccharide, Scattering, Seaweed
@article{FONTESCANDIA2020101873,
title = {Rheological and structural characterization of carrageenan emulsion gels},
author = {Cynthia Fontes-Candia and Anna Ström and Patricia Lopez-Sanchez and Amparo López-Rubio and Marta Martínez-Sanz},
url = {https://www.sciencedirect.com/science/article/pii/S2211926419312482},
doi = {https://doi.org/10.1016/j.algal.2020.101873},
issn = {2211-9264},
year = {2020},
date = {2020-01-01},
journal = {Algal Research},
volume = {47},
pages = {101873},
abstract = {Carrageenan emulsion gels containing sunflower oil were prepared using three different commercial carrageenan grades (κ-C, ι-C and λ-C). The effect of the carrageenan and salt content, as well as the oil:water ratio, on the emulsion gel strength was evaluated through a response surface methodology. Moreover, the rheological properties and the micro- and nanostructure from the stronger emulsion gel formulations were investigated and compared to their analogous hydrogel formulations. Interestingly, emulsion gels formed stronger and more thermally stable networks than the hydrogels, being this effect more evident in ι-C and λ-C. The results indicate that this was mainly due to a polysaccharide concentration effect, as no evidence of interactions between the carrageenan and the oil phase was found. Consequently, the rheological behaviour of the emulsion gels was mostly determined by the type of carrageenan. The association of carrageenan molecular chains was favoured in κ-C and λ-C (due to the presence of κ-carrageenan in the latter) and promoted by the addition of KCl. In contrast, a lower degree of chain association, mostly driven by ionic cross-linking, took place in ι-C. These results evidence the relevance of the gelation mechanism on the properties of emulsion gels and provide the basis for the design of these systems for targeted applications within the food industry.},
keywords = {Fat replacement, Gelation, Polysaccharide, Scattering, Seaweed},
pubstate = {published},
tppubtype = {article}
}
Carrageenan emulsion gels containing sunflower oil were prepared using three different commercial carrageenan grades (κ-C, ι-C and λ-C). The effect of the carrageenan and salt content, as well as the oil:water ratio, on the emulsion gel strength was evaluated through a response surface methodology. Moreover, the rheological properties and the micro- and nanostructure from the stronger emulsion gel formulations were investigated and compared to their analogous hydrogel formulations. Interestingly, emulsion gels formed stronger and more thermally stable networks than the hydrogels, being this effect more evident in ι-C and λ-C. The results indicate that this was mainly due to a polysaccharide concentration effect, as no evidence of interactions between the carrageenan and the oil phase was found. Consequently, the rheological behaviour of the emulsion gels was mostly determined by the type of carrageenan. The association of carrageenan molecular chains was favoured in κ-C and λ-C (due to the presence of κ-carrageenan in the latter) and promoted by the addition of KCl. In contrast, a lower degree of chain association, mostly driven by ionic cross-linking, took place in ι-C. These results evidence the relevance of the gelation mechanism on the properties of emulsion gels and provide the basis for the design of these systems for targeted applications within the food industry.
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