Jeb,
Interesting question. 36 months is a l-o-o-o-ong time for high fat troll
fish to remain edible. I have tried to eat 12 month old frozen troll fish
that had been well glazed and held in a -10 F freezer. The oxidative
rancidity was overwhelming.
Can't answer your question, but every step you describe involves eliminating
or restricting oxygen access to the fish. That's got to be a major point. As
for the desiccating effect of blast freezing, yeah ok, but what do you call
sucking the juice out with a vacuum?
As for cook from frozen vs. thaw and cook. Most of the new value added
seafood products (e.g. flavor glazed, breaded, herbed, pattied, etc) are
designed to be cooked from frozen and seem to suffer no ill effects.
Regards,
Jon McGraw
Seafreeze
Original Message-----
From: Jeb Wyman [mailto:jeb@pfmag.com]
Sent: Monday, March 18, 2002 11:54 AM
To: seafood@ucdavis.edu
Subject: extending salmon shelf life
Dear list:
I would be interested in knowing whether there is any validity to the claims
of extended cold storage shelf life using the unusual process below and, if
so, whether anyone can explain why it might work.
Troll-caught coho salmon are landed, bled, and put in 32-34 degree chill
tank for about 24 hours. After removing head, guts, and tail, the fish are
subjected to 30 inches of vacuum for about 1 minute. Although the fish may
appear spotless, this process nonetheless extracts a significant amount of
fluid from the fish. The fish are then carefully laid in a -50 degree
"soaker freezer" (i.e., a freezer hold with -50 ambient temperature but
without forced air circulation like a blast freezer, which allegely
dessicates the product). They are glazed several times. After one or two
months, the frozen carcasses are cut with a bandsaw into steaks, re-glazed
twice, and double-wrapped in vacuum packaging. This process is supposed to
greatly reduce oxidation. Apparently product as much as 36 month old is
still palatable.
I am interested in learning whether vacuum extraction of fluids could remove
lipids associated with rancification. Any science to support or de-bunk
this process?
On a slightly different topic, I would like to know how food quality may or
may not be compromised by directly cooking frozen product without a
slacking-out period. Thawing food prior to cooking seems to be the norm. If
there were no concerns that the food would cook unevenly or inadequately
(i.e., a sanitation issue), does cooking frozen product otherwise damage the
tissue and affect texture or taste?
Many thanks for any help you can lend me.
Jeb Wyman
Associate editor
Pacific Fishing/FIS
4209 21st Ave W
Seattle, WA 98199
206/216-0111 ext 215
FAX 206/216-0222
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