Calcium alginate

Jump to: navigation, search
Calcium alginate
Calcium alginate skeletal.png
IUPAC name Calcium β-D-mannopyranuronosyl-(1→4)- α-L-gulopyranuronosyl-(1→4)- α-L-gulopyranuronate
Other names E404
Identifiers
CAS number 9005-35-0
ATC code B02BC08
Properties
Molecular formula (C12H14CaO12)n
Appearance Solid
Hazards
LD50 >15g/kg[1]
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

Infobox disclaimer and references

WikiDoc Resources for Calcium alginate

Articles

Most recent articles on Calcium alginate

Most cited articles on Calcium alginate

Review articles on Calcium alginate

Articles on Calcium alginate in N Eng J Med, Lancet, BMJ

Media

Powerpoint slides on Calcium alginate

Images of Calcium alginate

Photos of Calcium alginate

Podcasts & MP3s on Calcium alginate

Videos on Calcium alginate

Evidence Based Medicine

Cochrane Collaboration on Calcium alginate

Bandolier on Calcium alginate

TRIP on Calcium alginate

Clinical Trials

Ongoing Trials on Calcium alginate at Clinical Trials.gov

Trial results on Calcium alginate

Clinical Trials on Calcium alginate at Google

Guidelines / Policies / Govt

US National Guidelines Clearinghouse on Calcium alginate

NICE Guidance on Calcium alginate

NHS PRODIGY Guidance

FDA on Calcium alginate

CDC on Calcium alginate

Books

Books on Calcium alginate

News

Calcium alginate in the news

Be alerted to news on Calcium alginate

News trends on Calcium alginate

Commentary

Blogs on Calcium alginate

Definitions

Definitions of Calcium alginate

Patient Resources / Community

Patient resources on Calcium alginate

Discussion groups on Calcium alginate

Patient Handouts on Calcium alginate

Directions to Hospitals Treating Calcium alginate

Risk calculators and risk factors for Calcium alginate

Healthcare Provider Resources

Symptoms of Calcium alginate

Causes & Risk Factors for Calcium alginate

Diagnostic studies for Calcium alginate

Treatment of Calcium alginate

Continuing Medical Education (CME)

CME Programs on Calcium alginate

International

Calcium alginate en Espanol

Calcium alginate en Francais

Business

Calcium alginate in the Marketplace

Patents on Calcium alginate

Experimental / Informatics

List of terms related to Calcium alginate

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

Calcium alginate is a water-insoluble, gelatinous, cream coloured substance that can be created through the addition of aqueous calcium chloride to aqueous sodium alginate. Adding artificial flavours and colours creates a more tasty edible slime. Calcium alginate is also used for entrapment of enzymes and forming artificial seeds in plant tissue culture.

"Alginate" is the term usually used for the salts of alginic acid, but it can also refer to all the derivatives of alginic acid and alginic acid itself; in some publications the term "algin" is used instead of alginate. Alginate is present in the cell walls of brown algae as the calcium, magnesium and sodium salts of alginic acid.

Preparation

Extraction of alginate

To extract the alginate, the seaweed is broken into pieces and stirred with a hot solution of an alkali, usually sodium carbonate. Over a period of about two hours, the alginate dissolves as sodium alginate to give a very thick slurry. This slurry also contains the part of the seaweed that does not dissolve, mainly cellulose. This insoluble residue must be removed from the solution. The solution is too thick (viscous) to be filtered and must be diluted with a very large quantity of water. After dilution, the solution is forced through a filter cloth in a filter press. However, the pieces of undissolved residue are very fine and can quickly clog the filter cloth. Therefore, before filtration is started, a filter aid, such as diatomaceous earth, must be added; this holds most of the fine particles away from the surface of the filter cloth and facilitates filtration. However, filter aid is expensive and can make a significant contribution to costs. To reduce the quantity of filter aid needed, some processors force air into the extract as it is being diluted with water (the extract and diluting water are mixed in an in-line mixer into which air is forced). Fine air bubbles attach themselves to the particles of residue. The diluted extract is left standing for several hours while the air rises to the top, taking the residue particles with it. This frothy mix of air and residue is removed from the top and the solution is withdrawn from the bottom and pumped to the filter.

Preparation of calcium alginate

The goal of the extraction process is to obtain dry, powdered, sodium alginate. The calcium and magnesium salts do not dissolve in water; the sodium salt does. The rationale behind the extraction of alginate from the seaweed is to convert all the alginate salts to the sodium salt, dissolve this in water, and remove the seaweed residue by filtration. The alginate must then be recovered from the aqueous solution. The solution is very dilute and evaporation of the water is not economic. To the Sodium alginate from the initial extraction solution, a calcium salt is added. This causes calcium alginate to form with a fibrous texture; it does not dissolve in water and can be separated from it with relative ease using a metal screen.

Uses

Uses of calcium alginate are:

References

  1. Gosselin, R.E., H.C. Hodge, R.P. Smith, and M.N. Gleason (1976). Clinical Toxicology of Commercial Products (4th ed.). Baltimore: Williams and Wilkins. p. II-155. 



Linked-in.jpg