![]() Rheological and structural properties of carrageenan gels can be tuned for a given polymer and salt concentration by adding both KCl and CaCl 2 to κ-car/ι-car mixtures. In mixed salt, K + induces formation of a homogeneous κ-car network that causes the mixed network to become more homogeneous. Gelation of κ-car increased the turbidity of mixed carrageenan gels in the presence of KCl or CaCl 2, but when both salts were present it led to a drop of the turbidity. At a given salt concentration, ι-car was stiffest with pure CaCl 2, but κ-car gels and mixed carrageenan gels were stiffer when both KCl and CaCl 2 were present. The gel temperature (T g) of ι-car was found to be determined by the CaCl 2 concentration and T g of κ-car by the KCl concentration. “Seaweed” is a common term for macroalgae.The effect was studied of adding both KCl and CaCl 2 on gelation of solutions of ι-carrageenan, κ-carrageenan and mixtures of both types. ![]() MOTW is proud to participate in the celebration.Ĥ. This year’s theme for Chemists Celebrate Earth Week is “ The Curious Chemistry of Amazing Algae”. The Prospector Knowledge Center published an excellent compendium of the three main carrageenan structures.ġ. They used the same formula as in the already-approved nasal spray mentioned above.Ī ScienceDirect information page provides much more information on ι-carrageenan. In a 2021 breakthrough, Andrea Vanesa Dugour and co-workers at the University of Buenos Aires and the César Milstein Institute of Science and Technology (Buenos Aires) discovered that ι-carrageenan prevents the replication of SARS-CoV-2 in vitro in the human respiratory epithelium cell line Calu-3. In another review, Manu Kumar at Dongguk University (Seoul) and colleagues noted that sulfated polysaccharides such as carrageenans attach tightly to the SARS-S protein, resulting in reduced viral infection. Iqbal at the Monterrey Institute of Technology and Higher Education (Mexico), Jingliang Xu at Zhengzhou University (China), and collaborators further reviewed literature that suggested that carrageenans and other algae molecules could prevent and treat SARS-CoV-2 infection. They also observed that the initially low levels of COVID-19 infection in Hokkaido Island (Japan) might be attributed to the residents’ widespread consumption of seaweed. Critchley at Cape Breton University (Sydney, NS) posed the question, “ seaweeds 4 to the rescue?” and wondered why the pharmaceutical community hadn’t investigated building on the known antiviral properties of carrageenans and other algae molecules to combat SARS-CoV-2, the virus responsible for COVID-19.Īmong several studies they cited, Pereira and Critchley noted that an ι-carrageenan-containing nasal spray provided relief of upper respiratory tract infections in patients suspected of having H 1N 1 influenza. In 2020, a few months into the COVID-10 pandemic, Leonel Pereira at the University of Coimbra (Portugal) and Alan T. In the past decade, scientists have studied carrageenans for what could turn out to be even more important uses: antiviral medications. The three major carrageenans have widely different gelling properties: Calcium ι-carrageenan forms soft gels potassium κ-carrageenan forms rigid gels and the λ-structure does not gel at all. ![]() They are also additives to common household products such as toothpaste, shampoo, air fresheners, and shoe polish. Historically, carrageenans have been used as thickening, gelling, emulsifying, stabilizing, and clarifying agents in food products ranging from ice cream to beer. Tseng at the Scripps Institute of Oceanography (La Jolla, CA) also wrote extensively about carrageenin and other algae-derived compounds. Rice at Dalhousie University (Halifax, NS) were among the first to describe carrageenans in the chemical literature (then by the name carrageenin), although they cited references to them as far back as 1844. ι- and κ-carrageenan occur in double-helix conformations. The counterions of the anionic carrageenans are typically sodium, potassium, and/or calcium. The ι-form, shown here, is found primarily in the alga Eucheuma denticulatum.Īll carrageenan polymers consist of repeating units of galactopyranose disaccharides, each of which contains zero, one, two, or three sulfate groups. At least 10 carrageenans are known the best known and most important ones are ι (iota)-, κ- 2, and λ- 3carrageenan. The carrageenans are a group of linear sulfated polysaccharides found in red algae 1 of the phylum Rhodophyta.
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