Page 33 - Natural Antioxidants, Applications in Foods of Animal Origin
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12 Natural Antioxidants: Applications in Foods of Animal Origin
VetBooks.ir E) which is considered as the most important natural AH. Tocopherol can
donate a hydrogen atom to the radicals L or LOO functioning as the mole-
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cule AH. It is generally assumed that the resulting tocopheryl radical reacts
with ascorbic acid (Vitamin C) at the lipid/water interface, regenerating
the tocopherol molecule. Muscle-based foods that contain relatively high
concentrations of α-tocopherol demonstrate greater lipid and oxymyoglobin
stability (Faustman et al., 1998). Poultry meat is composed of relatively high
levels of unsaturated fatty acids and low levels of natural tocopherols and
thus poultry products are very susceptible to the development of off-flavors
due to oxidative rancidity (Dawson & Gartner, 1983). According to Wilson
et al. (1976), turkey meat containing lower levels of natural tocopherol is
most susceptible to warmed-over-flavor (WOF) development, followed
closely by chicken, then by pork, beef, and mutton. The use of mechanically
deboned poultry meat enhances the tendency of poultry products to oxidize
(Moerck & Ball, 1974). However, the use of mechanically deboned beef
in beef meat products did not result in flavor deterioration during storage,
compared to control samples made of hand-boned beef, suggesting that lipid
oxidation is not a problem as with chicken and fish; this was attributed to
differences in the degree of unsaturation of fatty acids (Allen & Foegeding,
1981).
Other compounds, for example the carotenoids and phenols, have been
known to function as AH (Huss, 1995). Vareltzis et al. (2008) reported
that adding fish press juice to washed cod mince could inhibit hemo-
globin-mediated lipid oxidation of protein isolates obtained from cod
muscle (Gadus morhua). Press juice obtained from chicken breast muscle
also showed a potent inhibitor of hemoglobin-mediated lipid oxidation in
washed cod muscle (Li et al., 2005). The aqueous phase of chicken breast
muscle includes low-molecular-weight (LMW) components such as ascor-
bate, urate, glutathione, bilirubin, and histidine-containing dipeptides
(Chan et al., 1994). High-molecular-weight (HMW) components include
glutathione peroxidase, superoxide dismutase, catalase, transferrin, hapto-
globin, albumin, ceruloplasmin, and hemopexin (Decker, 1998). Erickson
et al. (1990) reported that both the LMW (<10 kDa) and HMW (>6–8 kDa)
cytosol fractions from flounder tissue inhibited iron-mediated lipid oxida-
tion in flounder sarcoplasmic reticulum and the effect was believed to be
due to the binding of iron. Furthermore, Slabyj and Hultin (1984) reported
that both LMW and HMW components in herring cytosol could inhibit iron-
mediated lipid oxidation in microsomes. Han and Liston (1989) reported the
ability of rainbow trout cytosol to inhibit iron-mediated lipid oxidation in
fish muscle microsomes.