Page 369 - Natural Antioxidants, Applications in Foods of Animal Origin

348 Natural Antioxidants: Applications in Foods of Animal Origin
VetBooks.ir b) Cooking

A typical treatment that greatly affects lipid oxidation is cooking. Heating
accelerates lipid peroxidation and volatile production in meat (Broncano et
al., 2009; Alfaia et al., 2010; Domínguez et al., 2014a, 2014b) by disrupting
muscle cell structure, inactivating antioxidant enzymes, and other antioxi-
dant compounds. In addition, cooking has the ability to increase iron concen-
trations in biological systems (which act as pro-oxidant) by stimulating the
release of iron from heme-proteins (Decker & Welch, 1990; Smiddy et al.,
2002; Richards, 2006). The resultant breakup of cell compartments permits
the interaction of pro-oxidants with unsaturated fatty acids and oxygen, the
generation of free radicals and propagation of the oxidative reaction (Asghar
et al., 1988). High temperature causes reduction of activation energy for
lipid peroxidation and decomposes preformed hydroperoxides to free radi-
cals, which stimulates autoxidation process and off-flavor development
further (Min et al., 2008).
In lipid oxidation, the most important parameters are the conditions
of heat treatment (temperature and time of cooking) (Byrne et al., 2002;
Domínguez et al., 2014a). The use of high temperature during cooking
causes an increase of the oxidation processes in meat (Broncano et al.,
2009). However, according to Domínguez et al. (2014a) oxidation processes
during cooking are more affected by cooking time than temperature. There-
fore, the application of heat during a long time produces higher oxidation
compared to the changes caused by the use of a higher temperature during
a shorter time.
The type of heating method used also has a great effect on the lipid
oxidation. While it is widely accepted that the microwave oven has greatly
contributed to the daily lives of modern society, the use of microwave
increase the lipid oxidation. Domínguez et al. (2014a) found that meat
cooked with microwave oven showed the highest values of TBARS. The fact
that samples cooked by microwave had high levels of oxidation compounds
suggests some interaction between microwave and meat fat which causes
oxidation of polyunsaturated fatty acids (Broncano et al., 2009).

c) High pressure

High-pressure processing is a non-thermal technology, which applies pres-
sures up to 1000 MPa for a variable time. It has been reported as a preserva-
tion method as it is able to extend the shelf life of food without modifying its