modified/crosslinked starch

There were questions earlier about superhardening gelatin.

I have been reading about colloids, trying to get a better sence of how
gum printing works.

I came across a reference (Emulsifiers by Clyde E. Stauffer) to a couple
of chemicals used to crosslink starches in food products. The crosslinked
starches form a stable gel across a variety of temperatures and pH's.

I quote from the book

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Crosslinked starch is starch that has been treated with one or more agents
to form bonds between glucose residues in adjacent starch chains.
 Sodium Trimetaphosphate or phosphorous trichloride form a phosphate
diester:
2 Starch + PO3Cl(NaOH) -> Starch-O-P(=O)(-O-)-O-Starch Na+
Epichlorohydrin forms a diether bridge, where the central moiety is a
hydroxypropyl group:
Starch-O-CH2-CH(-OH)CH2-O-Starch
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I don't know enough organic chemistry to know whether these chemicals
would form crosslinking in gelatin ( gelatin is a protein not a starch)
and contribute to its hardening.
Or could a crosslinked starch be used as an effective sizing?
Any comments?
Gord
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Gordon J. Holtslander		Dept. of Biology
holtsg@duke.usask.ca		112 Science Place
http://duke.usask.ca/~holtsg	University of Saskatchewan
Tel (306) 966-4433		Saskatoon, Saskatchewan
Fax (306) 966-4461		Canada  S7N 5E2
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