Structure and rheology of the κ-carrageenan/locust bean gum gels

Dunstan, Dave E.; Chen, Y; Liao, Ming-Long; Salvatore, Roberto; Boger, David V.; Prica, M.

doi:10.1016/s0268-005x(01)00054-6

Cited by 81 publications

(55 citation statements)

References 25 publications

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“…The quality of the images and high resolution are due to the new-generation microscope used. Similar supramolecular structures have been described in the case of mixed gels (Dunstan et al 2001).…”

Section: Scanning Electron Microscopysupporting

confidence: 77%

“…These methods often involve dehydrating samples after freezing structures at preferred states. To avoid shear-induced damage of supramolecular structures by formation and growth of ice crystals, microscopy techniques often involve several cryofixation methods, such as rapid freezing of samples in liquid propane or nitrogen at normal pressure or under vacuum (Dunstan et al 2001). Also cryo-SEM in combination with pressure-shift freezing is extensively used for direct imaging of the undisturbed real-space gel structures at the micron scale (Fuchigami et al 2006).…”

Section: Introductionmentioning

confidence: 99%

“…Numerous investigations have focused on the macroscopic gel structure of carrageenan blends with sugars, proteins or other industrial gums, such as agarose (Norziah et al 2006), locust bean gum (Dunstan et al 2001) and konjac gum (Medina-Torres et al 2006). It has been reported that at a high level of co-solutes, galactans are severely water deficient, resulting in the occurrence of polysaccharide chains as a sparsely cross-linked network (Evageliou et al 1998;Whittaker et al 1997).…”

Section: Introductionmentioning

confidence: 99%

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Gel-forming structures and stages of red algal galactans of different sulfation levels

et al. 2007

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Sol-gel transition processes of algal galactans were studied using cryofixation method in combination with freeze-drying and scanning electron microscopy (SEM) techniques. The structures formed in successive stages of gelling process upon cooling were rapidly frozen at defined temperature points and viewed by SEM. It was established that in the case of both types of gelling galactans investigated, a fine honeycomb-like network exists for a wide range of solution temperatures. The formation and structure of this network depends on the structural type, gelling stage, and concentration of the galactan in solution. The honeycomb suprastructures exist also in carrageenan and agarose sols (at temperatures considerably exceeding the gelling temperatures). An additional helical network formed showed different behaviour in the case of carrageenan and agar-type polysaccharides. In the gel-formation process, tightening of the network takes place in both types of galactan gels; the honeycomb structures persist in carrageenan (furcellaran) but not in agarose gels.

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Section: Scanning Electron Microscopysupporting

confidence: 77%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Gel-forming structures and stages of red algal galactans of different sulfation levels

et al. 2007

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“…SEM micrographs showed a characteristic honeycomb pattern to be present in furcellaran gels. Similar supramolecular structures have also been described in the case of mixed gels (Dunstan et al 2001).…”

Section: Scanning Electron Microscopysupporting

confidence: 76%

The extraction, structure, and gelling properties of hybrid galactan from the red alga Furcellaria lumbricalis (Baltic Sea, Estonia)

et al. 2009

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The structure and composition of galactan from Furcellaria lumbricalis (furcellaran) were investigated in connection with rheological specificities, gel structure, and extraction conditions. The polysaccharide was characterized by 13 C nuclear magnetic resonance ( 13 C-NMR) and Fourier transform infrared spectroscopy, inductively coupled plasma-optical emission spectrometry, electrothermal atomization atomic absorption spectrometry, and gel permeation chromatography methods. The microstructure of polymer gels was studied using a cryofixation method in combination with freeze-drying and scanning electron microscopy (SEM) techniques. The undersulfated furcellaran backbone consists mainly of 3,6-anhydro-D-galactose (28.5-30.1%) and galactose residues, the latter being partly sulfated in positions 4 and 6, which give rise to some specific properties of the gel. Also, residues of 6-O-methyl-Dgalactose as a minor component are found to be present. The water-extracted furcellaran with the average molecular weight about 290 kDa is rich in nitrogen, calcium, magnesium, and potassium, while the sodium content is rather low. The low sulfur content (5.3%) and 13 C-NMR spectra refer to an undersulfated nature of this galactan. The extraction of seaweeds in low concentration alkaline solutions (instead of water) leads to a significant increase of the minimum size of the galactan particles and the value of gel strength (more than 12 times for Rb-containing gels). The properties of the gel are dependent on specific tentaclelike structure units present in furcellaran gels established by a high-resolution SEM.

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“…Guar and locust bean gums are galactomannans having different water solubilities due to the difference in the degree of galactose substitution (Kok et al 1999). While guar gum having higher galactose content swells and disperses almost completely in both cold and hot water, locust bean gum (LBG) needs to be heated for complete solubility (Wang et al 2000;Dunstan et al 2001). Viscosity usually ranges from 6000 to 7500 mPas for guar and 3000-3500 for LBG dispersions at 1% solids (Alexander 1999a).…”

Section: Thickening Agentsmentioning

confidence: 99%

Hydrocolloids as thickening and gelling agents in food: a critical review

2010

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Hydrocolloids are widely used in many food formulations to improve quality attributes and shelf-life. The two main uses are as thickening and gelling agents. As thickening agents, they find uses in soups, gravies, salad dressings, sauces and toppings while as gelling agents, they are extensively used in products like jam, jelly, marmalade, restructured foods and low sugar/calorie gels. The role of specific hydrocolloids for thickening and for gel formation is reviewed pinpointing specific applications in food formulations and for product development.

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Structure and rheology of the κ-carrageenan/locust bean gum gels

Cited by 81 publications

References 25 publications

Gel-forming structures and stages of red algal galactans of different sulfation levels

Gel-forming structures and stages of red algal galactans of different sulfation levels

The extraction, structure, and gelling properties of hybrid galactan from the red alga Furcellaria lumbricalis (Baltic Sea, Estonia)

Hydrocolloids as thickening and gelling agents in food: a critical review

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