Characterization of alginates from Ghanaian brown seaweeds: Sargassum spp. and Padina spp.

Rhein‐Knudsen, Nanna; Ale, Marcel Tutor; Ajalloueian, Fatemeh; Meyer, Anne S.

doi:10.1016/j.foodhyd.2017.05.016

Cited by 137 publications

(96 citation statements)

References 40 publications

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“…Because large pores may be suitable for cell attachment in the inner parts of a scaffold, the HA/alginate scaffold may offer an alternative for bone tissue engineering. Alginate [(C 6 H 7 O 6 Na) n ], a natural resource of polysaccharides derived from brown seaweed, composed of 1-4-β-D mannuronic and L-guluronic acids contains a large number of pendant carboxylic acid groups, which provide sites for heterogeneous mineral nucleation [23][24][25]. Alginate is highly hydrophilic that can form stable hydrogels in the presence of certain divalent cations, such as Ca2+, Mg2+, Fe2+, Ba2+, or Sr2+.…”

Section: Introductionmentioning

confidence: 99%

Preparation and Characterization of Porous Hydroxyapatite and Alginate Composite Scaffolds for Bone Tissue Engineering

2018

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Objective: To prepare and characterize composite scaffolds of a hydroxyapatite (HA) and an alginate having high viscosity. Materials and Methods:HA powder was synthesized using wet chemical precipitation, the alginate powder was extracted from the Sargassum duplicatum seaweed, and the HA/alginate composite scaffolds were prepared by freeze-drying. X-ray diffraction and Fourier transform infrared techniques were utilized to characterize the HA and alginate, and electron microscopy was used to evaluate the HA and the HA/alginate composite scaffolds. The HA/alginate composite scaffold obtained from the commercially available HA and alginate powders were employed as a comparison.Results: Synthesized HAs were identified as the HA phase, which contained absorbed water, phosphate, and carbonate groups. The extracted alginate contained the carboxyl, cyclic ether and hydroxyl groups. The scaffolds prepared from the HA and alginate mixture were three-dimensional and containing interconnected pores with a diameter ranging from 150 to 300 µm and pore walls of a composite construction. Conclusion:A three-dimensional scaffold was produced using a freeze-drying method from a composite of HA and the high viscosity alginate solution. The scaffold was highly porous and showed interconnected pores, with a diameter ranging from 150 to 300 µm.

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Section: Introductionmentioning

confidence: 99%

Preparation and Characterization of Porous Hydroxyapatite and Alginate Composite Scaffolds for Bone Tissue Engineering

2018

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“…This temperature reduction for only the green seaweed can be attributed to the weaker α-1,4-glycosidic linkages found in the starch fraction of U. fasciata. These are easier to breakdown than the β-1,4glycosidic linkages (between mannuronic and guluronic acid) found in the alginate fraction of S. vulgare and the β-1,3-glycosidic linkages in agar found in H. dentata which are structurally more stable [32]. Meinita et al [33] noted a reaction time, temperature and catalyst concentration of 15 min, 130 °C and 0.2 M, respectively, as the optimal dilute acid hydrolysis condition from their work on the red seaweed, Kappaphycus alvarezii.…”

Section: Optimal Acid-catalysed Hydrolysis Of the Selected Seaweedmentioning

confidence: 93%

Cellulase and acid-catalysed hydrolysis of Ulva fasciata, Hydropuntia dentata and Sargassum vulgare for bioethanol production

2019

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Hydrolysis in bioethanol production is one of the most limiting stages in the entire production process since it is the stage where the sugars to be converted to ethanol are obtained. Ulva fasciata, Hydropuntia dentata and Sargassum vulgare seaweeds were examined in this study to determine the most efficient pretreatment, optimal hydrolysis conditions and predictive models with dilute sulphuric acid and cellulase enzyme as catalysts. Dilute acid pretreatment was found to be the most efficient in maximizing the catalytic efficiency of enzymes applied on all the three selected seaweeds. Ulva fasciata, however, was found to be efficiently hydrolysable without any form of pretreatment. The study also found dilute sulphuric acid hydrolysis to be less effective since it released up to 52.4% of reducing sugars in the seaweeds as compared to the 90.9% from hydrolysis with cellulase enzyme. Also, the most efficient regression model between the seaweed species studied was obtained for the enzymatic hydrolysis of U. fasciata with a correlation coefficient of 99.4%. This indicates a high precision in predicting the reducing sugar yields from the species within boundary conditions. Overall, the optimal enzymatic hydrolysis process was influenced most by substrate concentration for all three seaweeds examined.

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“…Several authors [4,12,13,27,29,36,39,43] before extraction of alginates from brown seaweeds performed soaking of algae in formaldehyde/formalin (usually 1-12 h) in order to soften the seaweed tissue, bleaching algal biomass and avoid alginate pigmentation [3,5,27]. The solution of formaldehyde reacts with algal phenolic compounds, polymerize and make the colouring substances insoluble [43].…”

Section: Conventional Extraction Of Alginates From Brown Seaweedsmentioning

confidence: 99%

“…In the work of Andriamanantoanina and Rinaudo [2] it was shown that the bleaching of brown algae before extraction (e.g., with chlorine) favoured the yield of extraction possibly due to the swelling of the algae cell walls. The treatment of seaweeds before extraction of alginates with diluted mineral acids is considered by many authors as an essential step that makes the alginate more readily soluble in an alkaline solution [5,8,9,13,23,35,36] etc., (see Table 1). More precisely, the acidification of algae can have several goals, for example it is necessary (1) to remove external salts and residual formaldehyde [3], 2to remove non-target compounds such as polyphenols and other polysaccharides such as fucoidans and laminarins [27,44] and (3) to provide acidic condition up to pH 4 where alginate salts, for example with calcium, sodium, potassium are converted to alginic acid which is then more easily converted into soluble sodium alginate during extraction with sodium carbonate [3,13,44].…”

Section: Conventional Extraction Of Alginates From Brown Seaweedsmentioning

confidence: 99%

“…Alginates are also characterised by unique biological and pharmacological properties [11]. In the food and pharmaceutical industry they mainly act as a gelling agent, stabilizer and thickener [2,13]. Nowadays, several applications of alignates have been seen, mainly as food additives to stabilize and improve food consistency (e.g., baked food, fruit industry, jellies, jams, ice cream, mayonnaise) [11,[14][15][16].…”

Section: Introductionmentioning

confidence: 99%

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Methods of extraction, physicochemical properties of alginates and their applications in biomedical field – a review

2019

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In this paper, the current state-of-art of extraction of alginates and the determination of their physico-chemical properties as well as their overall applications focussing on biomedical purposes has been presented. The quality and quantity of the alginate obtained with a variable yield prepared from brown seaweeds as a result of many factors, such as type of algae, extraction methods, chemical modification and others. Alginates are mainly extracted by using conventional alkaline extraction. However, novel extraction techniques such as microwave and ultrasound assisted extractions have gained a lot of interest. The extraction parameters (e.g., temperature and time of extraction) have critical impact on the alginate physiochemical and mechanical properties and thus, their potential applications. By controlling a chemical process makes it possible get various forms of alginates, such as fibres, films, hydrogels or foams. It is important to characterise the obtained alginates in order to their proper applications. This article presents several techniques used for the analysis of alginate properties. These natural polysaccharides are widely used in the commercial production, as a food ingredient, in the pharmaceutical industry due to their antibacterial, anticancer and probiotic properties. Their gelling characteristic and absorbable properties enable using alginates as a wound management material. Moreover, they are also biocompatible, non-toxic and biodegradable, therefore adequate in other biomedical applications.

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Characterization of alginates from Ghanaian brown seaweeds: Sargassum spp. and Padina spp.

Cited by 137 publications

References 40 publications

Preparation and Characterization of Porous Hydroxyapatite and Alginate Composite Scaffolds for Bone Tissue Engineering

Preparation and Characterization of Porous Hydroxyapatite and Alginate Composite Scaffolds for Bone Tissue Engineering

Cellulase and acid-catalysed hydrolysis of Ulva fasciata, Hydropuntia dentata and Sargassum vulgare for bioethanol production

Methods of extraction, physicochemical properties of alginates and their applications in biomedical field – a review

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