Re: Autoclaving gum and gelatin

From: Ryuji Suzuki ^lt;rs@silvergrain.org>
Date: 02/05/05-05:36:32 PM Z
Message-id: <20050205.183632.25476883.lifebook-4234377@silvergrain.org>

Gelatin is a partially degraded collagen, which is the tough stuff
found in the cheap cuts of meat, skin and bone. Collagen can be
degraded by heat treatment, which requires many minutes of heating at
about 95C. This is why people can make delicious stew out of tough
cuts, and the liquid part of the stew makes stiff jelly when
refrigerated. Equally delicious stew can be made at about 1/3 of the
time by using a good pressure cooker capable of twice the atomospheric
pressure, which makes the boiling point of water to be about 120C.
(Crappy pressure cookers can't reach that high.) That is, gelatin
itself is viable at these temperatures and duration of heating.

Commercial manufacturing of gelatin use strong acid or base to degrade
collagen. Food gelatin is usually made by acid process of pigskin,
and photographic gelatin by lime (base) process of cow bones.

Gelatins do get broken down in harsh conditions, but not that easily.
Bacterial growth is probably the most common cause of gelatin
breakdown.

--
Ryuji Suzuki
"People seldom do what they believe in.  They do what is convenient,
then repent." (Bob Dylan, Brownsville Girl, 1986)
Received on Sat Feb 5 17:36:48 2005

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