Andrew Strak (abstrak@accesswave.ca)
Fri, 28 Jan 2000 08:02:47 -0400
John,
It appears that formaldehyde related protein aggregation with the resulting
decrease in water holding capacity of the flesh is more common and
pronounced in Pacific gadids such as Pacific cod or Alaska pollock than in
the Atlantic family of gadoid species. Would you have any explanation for
what generally is possibly higher TMAO content in North Pacific gadids?
Regards,
Andrew Strak
----- Original Message -----
From: John French <frenchpe@concentric.net>
To: <abstrak@accesswave.ca>
Cc: <marcie@eznet.net>; <klyman@tiac.net>; <seafood@ucdavis.edu>
Sent: Thursday, January 27, 2000 4:20 PM
Subject: Re: Determining if Cooked Salmon is Fresh or previously Frozen
Product
> seafood list:
>
> For what it is worth, about 15 years ago I published a report showing a
> correlation between the time in frozen storage, and partially frozen,
storage,
> and the level of high molecular mass aggregates monitored by SDS-PAGE.
These
> were presumably formed by formaldehyde dependent aggregation and do indeed
show
> that molecular level changes in the proteins are occurring in frozen
salmon
> (coho & sockeye) during even relatively short (0-3 weeks) storage.
>
> While quite sensitive, this is not a method easily adapted to routine
testing.
> As others have said, careful visual inspection usually works.
>
> John French, Ph.D.
> PEGASUS ENTERPRISES
>
> Andrew Strak wrote:
>
> > Marcie,
> >
> > I think that you in general it is a pretty valid test. But it may not
always
> > work with freshly quick frozen salmon, though. The cell rupture and loss
of
> > water holding capacity of the flesh are also impacted by time in frozen
> > storage. Farmed Atlantic salmon, as most fatty species, freezes well and
> > there is very little freeze denaturation durning first days or even
weeks
> > of storage. But after one month and on the difference between fresh and
> > previously frozen would become more obvious due to reasons that have
been
> > discussed.
> >
> > Andrew Strak
> >
> > ----- Original Message -----
> > From: Marcie Ver Ploeg <marcie@eznet.net>
> > To: <klyman@tiac.net>
> > Cc: <seafood@ucdavis.edu>
> > Sent: Wednesday, January 26, 2000 11:25 PM
> > Subject: Re: Determining if Cooked Salmon is Fresh or previously Frozen
> > Product
> >
> > > Kevinn:
> > > Don't know if this answer is based on "good science" or not. In
Seafood
> > Cooking for Dummies [1999, IDGBooks, page 82], we included this "Fish
> > Masters" tip (from Captain Jack Donlan, who's been selling fish (retail
and
> > wholesale) in Grand Blanc, Michigan, for fifty years): "Try to gently
fold a
> > fillet in half, end-to-end, with skin side out (or what would have been
the
> > skin side if it's skinless). A previously frozen fillet will ooze
moisture
> > from the midpoint. A fresh one won't drip, because its cell walls
haven't
> > been ruptured by freezing and thawing."
> > > I ran the "test" several times (works best on thinner fillets) and
found
> > it generally valid.
> > >
> > > Marcie Ver Ploeg
> > > co-author Seafood Cooking for Dummies
> > > VP Communications (stands for Ver Ploeg, not Vice President!)
> > > Pittsford NY
> > >
> > > *********** REPLY SEPARATOR ***********
> > >
> > > On 1/26/00 at 3:39 PM kevin lyman wrote:
> > >
> > > >We had an issue at our company the other day where a customer claimed
> > that
> > > >we had
> > > >tried to sell previously frozen salmon as fresh. Does any one have
any
> > > >tips on how to tell whether the product after cooking was fresh or
> > > >previously frozen? I consider color and moisture to be possible
> > > >indicators, with previously frozen being lighter in color and drier.
Any
> > > >help will be appreciated.
> > > >
> > > >Thank you
> > > >Kevinn Lyman
> > > >John Nagle Co.
> > > >Boston, Ma.
> > >
> > >
> > >
>
>
>
This archive was generated by hypermail 2.0b3 on Fri Jan 28 2000 - 04:07:04 PST