Dear Sue
You are looking for 'published data on nutritional or compositional
comparisons of fish in the raw chilled state and after having been frozen'.
With regard to compositional comparisons, yes, there are data on differences
between the two, depending on how fine a detail you are looking for. These
might affect subtle aspects of nutrition in the broad sense, but freezing
and frozen storage will not affect the gross composition and nutritional
properties of fish. Let me quote from the UK's Ministry of Agriculture,
Fisheries and Food, 1995, Manual of Nutrition. Reference Book 342. 10th
edition., HMSO, London. ISBN 0 11 242991 2, p 91: 'Modern methods of
freezing do not affect the nutritive value, and poaching and steaming incur
only small losses of vitamins. Between 10 and 30 per cent losses of
B-vitamins occur on baking, frying or grilling.'. That is, normal cooking
methods cause more loss of nutrients than does freezing. I do not know why
the text quoted refers to 'modern methods'; I would not expect old methods
of freezing to affect nutritive value of frozen fish either.
There are chemical changes during storage of frozen fish, for example,
changes in nucleotide composition, formation of formaldehyde and
dimethylamine, oxidation of lipids, the amount of change depending on
temperature and time of storage, and method of packaging, and there is a
large literature on these effects. I would not expect these changes to
affect nutritive value in the sense of causing loss of nutrients, though I
think there could be some debate about possible toxic effects of, say,
formaldehyde or some lipid oxidation products. Off-hand, I can not recall
any published discussion on these matters.
Peter Howgate
----- Original Message -----
From: "Poole, Sue" <Sue.Poole@dpi.qld.gov.au>
To: <seafood@ucdavis.edu>
Sent: Tuesday, November 26, 2002 2:18 AM
Subject: fresh vs frozen fish
> Hello List members
> Please can anyone help.....
> I am searching for published data on nutritional or compostional
> comparisons of fish in the raw chilled state and after having been
> frozen.
> When the query was posed to me - I thought such info would be readily
> attainable
> However - I have turned up extremely little anywhere.....!? despite
> thorough searches of abstract databases, every likely search engine and
> website I can think of....
> Does anyone know anyone who has carried out studies in this area?? even
> information on consumer perception studies of chilled and frozen fish
> product would be of interest...
> Any lead at all would be very gratefully received...
> Thank you..
> and Best Regards
> Sue
> Sue Poole
> Senior Seafood Microbiologist
> Centre for Food Technology
> Queensland Department of Primary Industries
> 19 Hercules St, Hamilton 4007
> Voice: +61 7 3406 8689 Fax: +61 7 3406 8698
> Email: sue.poole@dpi.qld.gov.au <mailto:sue.pooles@dpi.qld.gov.au>
>
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