Indian tragacanth, karaya gum, sterculia gum, E 416
|Monomers / partial structures||D- galactose , L- rhamnose , D- galacturonic acid , D- glucuronic acid acetic acid|
|Type of polymer|
|As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .|
Karaya ( Indian tragacanth , karaya gum , sterculia gum , E 416) is a gum that mainly consists of carbohydrates and galacturonic acid . It is an acidic polysaccharide made from D- galactose , L- rhamnose , D- galacturonic acid, D- glucuronic acid and acetic acid . The light powder accordingly has a vinegar-like odor.
Karaya is often confused with , even equated with, kutira gum , this comes from ( Cochlospermum spp. ), This is often used as a surrogate. Karaya is used as a substitute for the more expensive tragacanth .
Karaya is of vegetable origin. It is the dried exudate of various types of Indian Sterculia ( Sterculia spp. ), In particular as Gulu known Sterculia urens . The tree is found mainly in the central Indian provinces and is traditionally used there.
Karaya can vary widely in its chemical composition, accordingly there are a number of different compositions that are summarized under Karaya. Four different possibilities are given as the sum formula: C 6 H 12 O 6 , C 6 H 12 O 5 , C 6 H 10 O 7 and C 2 H 4 O 2 , which also differ significantly in their molar mass (180.16 g · mol -1 , 164.16 g · mol -1 , 194.14 g · mol -1 , 60.05 g · mol -1 ). The molar mass of the total polymer can be up to 9,500,000 g · mol −1 .
Pure Karaya is translucent white and does not contain any impurities, purities on the market contain up to 3 percent impurities from bark components and the like, their coloration varies from light yellow to brown. As a powder, Karaya is white to gray and has a distinct vinegar odor.
Due to its high swellability, karaya gum is added to foods (snacks, sauces, chewing gum , eggnog ) and medicines as a gelling and thickening agent. In the EU , it has limited approval as a food additive with the number E 416 for so-called " organic products ".
Karaya gum has a slight laxative effect in high doses. Corresponding finished medicinal products are on the market in other European countries. But not in Germany. Impaired mineral absorption (of e.g. calcium ) can occur as an undesirable effect .
- data sheet Karaya gum at Sigma-Aldrich , accessed on June 13, 2011 ( PDF ).
- Keyword Karaya Gum. In: Hans Zoebelein (Ed.): Dictionary of Renewable Resources. 2nd edition, Wiley-VCH, Weinheim and New York 1996; P. 92. ISBN 3-527-30114-3 .
- Gerhard Eisenbrand, Peter: RÖMPP Lexikon Lebensmittelchemie. 2nd edition, Thieme, 2006, ISBN 978-3-13-736602-7 , p. 593.
- Peter A. Williams, Glyn O. Phillips: Gums and Stabilisers for the Food Industry 16. RSC Publishing, 2012, ISBN 978-1-84973-358-8 , p. 99.
- Additive Admissions Ordinance
- Karaya-gummi (PDF; 422 kB), from kolleg.loel.hs-anhalt.de, accessed on January 9, 2017.