Page 44 - Natural Antioxidants, Applications in Foods of Animal Origin

Mechanism of Oxidation in Foods of Animal Origin 23
VetBooks.ir lipid oxidation and the subsequent propagation of lipid oxidation. However,

Richards and Dettmann (2003) postulated that perch and trout deoxyhemo-
globin could stimulate lipid oxidation in washed cod muscle during storage
at 4 °C as evidenced by the formation of lipid peroxides and TBARS. A more
rapid formation of methemoglobin from deoxygenated molecules, deoxyhe-
moglobin, likely increases the lipid oxidation (Richards et al., 2002).

1.6.2 ROLE OF OXYMYOGLOBIN IN LIPID OXIDATION

Oxymyoglobin oxidation and lipid oxidation are coupled (Yin & Faustman,
1993). A high correlation between oxymyoglobin oxidation and lipid oxida-
tion both in microsomes and liposomes was reported by Yin and Faustman
(1993, 1994) and O’Grady et al. (2001). Lipid oxidation in fresh meat is
influenced by the oxidation of oxymyoglobin since the oxymyoglobin
oxidation results in production of two species known as the prooxidants,
namely metmyoglobin and H O (Chan et al., 1997a, 1997b). It has been
2
2
proposed that O and H O are produced during oxidation of oxymyoglobin
•-
2
2
2
to metmyoglobin (Gotoh & Shikama, 1976). O can further react with H O
•-
2
2
2
and Fe via the Fenton reaction to produce OH and facilitate lipid oxida-
•
3+
tion (Chan et al., 1997a, 1997b). The prooxidative effect of oxymyoglobin
toward lipid oxidation was concentration-dependent (Chan et al., 1997a,
1997b). Additionally, H O can react with metmyoglobin to form a prooxi-
2
2
dative ferrylmyoglobin radical (Decker & Hultin, 1992). Kanner and Harel
(1985) reported that H O -activated metmyoglobin caused the rapid oxida-
2
2
tion of poultry skeletal muscle microsomes. Moreover, reactive oxygen
species including superoxide, hydroperoxyl radical (HOO ), and H O , orig-
•
2
2
inated by the autoxidation of oxymyoglobin (Kruger-Ohlsen & Skibsted,
1997), can cause damage to muscle lipids via oxidation reaction (Skulachev,
1996; Hultin & Kelleher, 2000).
Prooxidative activity of oxymyoglobin in a myoglobin-liposome system
was concentration-dependent and showed the higher activity than did
metmyoglobin. The added sperm whale myoglobin was found to promote
lipid oxidation in washed cod by which lipid oxidation occurred more rapidly
at pH 5.7 compared to pH 6.3 (Grunwald & Richards, 2006b). Prooxidative
activity of oxymyoglobin is difficult to assess because of continuous autoxi-
dation of oxymyoglobin to metmyoglobin. Chan et al. (1997a) and Yin and
Faustman (1993) reported a high correlation between oxymyoglobin oxida-
tion and lipid oxidation both in microsomes and liposomes system. The role
of oxymyoglobin oxidation in lipid oxidation was reported by Chan et al.