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FOOD IRRADIATION
I apologize in advance if the following duplicates some of the
comment on food irradiation, but I've got 800 email messages to plow
through and have been unable to follow the thread completely. Also,
apologies for most misspellings.
The May 1994 issue of _Food Technology_ contains several articles
on food irradiation. On article on "The Wholesomeness if Irradiated foods"
by Donald W. Thayer (p 132 ) contains the following:
"There are questions about other irradiated products that need to be
addressed, ,in particular the potential loss of vitamin C from fruit
or vegetables irradtiated for insect control. The issue is complicated
because fruits and vegetables are living tissue. Ascorbic acid is a
sensitive redox compound. Even at doses below 1 kGy, such as those
approved for insect control, some ascorbic acid will be converted to its
oxidized dehydro form (Romani, et al. 1963). Dehydroascorbic acid,
however, is fully as active as the reduced form of the vitamin.
Unfortunately, many of the studies in the literature did not use assay
methods that would detect the oxidized form of the vitamin and thus
reported erroneously high losses. During storage of irradiated potatoes,
much of the dehydro form is converted back to the reduced form. However,
in selected products, some loss appears to be irreversible, especially at
radiation doses > 1 kGy (Thayer et al., 1991). These losses do not
appear to be significant at doses intended to control insects in fruits
(<1 kGy) and are lower than those from freezing (Beyers and Thomas, 1979)"
References mentioned:
Beyers, M and Thomas AC, 1979
Irradiation of subtropical fruits. 4. Changes in certain nutrients
present in mangoes, papayas, and litchis during canning, freezing,
and [gamma] irradiation. J. Agric. Food Chem. 27:48
Romani, RJ, Van Kooy, J, Lim, L, and Bowers, B, 1963
Radiation physiology of fruit - Ascorbic acid, sulfhydryl and
soluble nitrogen content of irradiated citrus. Radiat. Biol. 3:58
Thayer, DW, Fox, JB Jr, and Lakritz, L, 1991
Effects of ionizing radiation on vitamins. Chapt. 11 in
"Food Irradiation" ed. S. Thorne, p 285, Elsevier Applied Science
Publishers, London
I would be happy to fax the article to anyone who requires it, but
it may take several months for me to get through my email. My apologies
to Mssrs. Gabbard & Zapantis for late replies to earlier queries - I'm
really still working on them.
___________________________________________________________________
Don Jordan Tel. (312) 702-6299
Office of Radiation Safety Fax 702-4008
The University of Chicago email: don@radpro.uchicago.edu
1101 East 57th Street, Room 11
Chicago, Illinois 60637
-- Any opinions are the author's --