Re: gum arabic
P.S. The term "gum arabic" is used rather loosely, sometimes to refer
to acacia senegal, sometimes to gum acacia of any variety, and
sometimes even to other species, so I wouldn't put too much faith in
the term "gum arabic" as being synonymous with acacia senegal.
kt
On Jan 17, 2009, at 9:18 AM, Alberto Novo wrote:
Also, sort is important; the kordofan, labeled (1) will be a
higher (finer) sort than the other, at sort 3. Hope that's helpful,
Katharine
As for Kremer's gum arabic, their pdf on their gum details is the
same for the three qualities, though their prices are different, so
I am wondering what they really are. I am not buying from Kremer,
because I have about 1 kg of gum arabic of unknown origin since a
long time (though it works well).
About Acacia senegal (cited from Kremer pdf):
"Gum Arabic is a dried exudate obtained from the stems and branches
of Acacia senegal (L.) Willdenow or closely related species of
Acacia (fam. Leguminosae). A. seyal is a closely related species.
Gum arabic consists mainly of high-molecular weight polysaccharides
and their calcium, magnesium, and potassium salts, which on
hydrolysis yield arabinose, galactose, rhamnose, and glucuronic
acid. Items of commerce may contain
extraneous materials such as sand and pieces of bark which must be
removed before use in food. Gum arabic from A. seyal is sometimes
referred to as gum talha."
"Gum Arabic from A. senegal is a pale white to orange-brown solid,
which breaks with a glassy fracture. The best grades are in the
form of whole, spheroidal tears of varying size with a matte
surface texture. When ground, the pieces are paler and have a
glassy appearance. Gum from other acacia species may not have the
characteristic tear shape and are often darker in colour. Gum from
A. seyal is more brittle than the hard tears of A. senegal."
One among the differencies (not easily testable at home) is their
optical properties: water solutions from A. senegal are
levorotatory, from A. are dextrorotatory.
Alberto
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