Page 25 - Natural Antioxidants, Applications in Foods of Animal Origin

4 Natural Antioxidants: Applications in Foods of Animal Origin
VetBooks.ir (PUFA) and other lipid substrates, causing significant losses in food quality,

health, and well-being (Chaijan et al., 2006; Chaijan, 2008). Lipid oxidation
in food systems is a detrimental process. It is difficult to find a food compo-
nent that would not be capable of affecting lipid oxidation because lipids are
only a part of a food product (Kolakowska, 2002). Generally, lipid oxidation
deteriorates the sensory quality and nutritive value of a product, poses a
health hazard, and presents a number of analytical problems (Kolakowska,
2002). Lipid oxidation is also one of the main factors limiting the quality
and acceptability of meats and other muscle foods, especially following
refrigerated and frozen storages (Zamora & Hidago, 2001; Renerre, 2000;
Morrissey et al., 1998). Oxidation of lipids is accentuated in the immediate
post-slaughter period, during handling, processing, storage, and cooking.
This process leads to discoloration, drip losses, off-odor and off-flavor devel-
opment, texture defects, and the production of potentially toxic compounds
in meat products (Richards et al., 2002; Morrissey et al., 1998).
Hydroperoxide is a primary oxidation product during storage of foods
which is readily decomposed to a variety of volatile compounds including
aldehydes, ketones, and alcohols (Frankel et al., 1984). The formation of the
secondary lipid oxidation products is one of the main causes of the devel-
opment of undesirable odors in muscle foods. Human olfactory receptors
usually have remarkably low organoleptic thresholds to most of these vola-
tile compounds (Ke et al., 1975; McGill et al., 1977). The effect of lipid
oxidation and off-odor development in postmortem fish has been reported.
Lipid oxidation is mainly associated with the rejection by consumer due to
the off-odor and off-flavor. Flavor is a very complex attribute of meat palat-
ability. Rancid or fishy odor has been identified as a common off-flavor asso-
ciated with fish flesh and directly related with the formation of the secondary
lipid oxidation products (Ke et al., 1975; McGill et al., 1977; Sohn et al.,
2005; Thiansilakul et al., 2010). Varlet et al. (2006) reported that carbonyl
compounds, such as heptanal or (E,Z)-2,6-nonadienal, show a high detection
frequency and odorant intensity in salmon (Salmo salar), giving the flesh its
typical fishy odor. The fishy volatiles identified in the boiled sardine were
dimethyl sulfide, acetaldehyde, propionaldehyde, butyraldehyde, 2-ethyl-
furan, valeraldehyde, 2,3-pentanedione, hexanal, and 1-penten-3-ol (Kasa-
hara & Osawa, 1998).
Lipid oxidation usually causes a decrease in consumer acceptance.
However, in some cases, lipid oxidation leads to enhancement of product
quality such as the enzymatic production of fresh fish aromas and the cured
meat flavor derived from lipid oxidation during ripening (Ladikos & Lougo-
vois, 1990). A notable exception is observed in dry cured country hams and