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14 Natural Antioxidants: Applications in Foods of Animal Origin
VetBooks.ir This phenomenon was postulated to have resulted from AH substances
produced from browning reactions during the heating of meat. It has been
reported that Maillard reaction products possessed AH activity which can be
applied as natural AH in food products (Limsuwanmanee et al., 2014).
The effect of drying method on oxidative stability of microencapsulated
fish oil with ratio of 33/22, EPA: DHA which emulsified with four combina-
tions of matrices was studied by Anwar and Kunz (2011). The emulsions
were dried by spray granulation, spray drying, and freeze drying to produce
25% oil powders. A combination of 10% soybean soluble polysaccharide
and 65% octenyl succinic anhydride dried by spray granulation was the best
procedure for fish oil encapsulation due to its having a very low propanal
content. The microcapsules produced by spray granulation might be then
covered by successive layers resulting in multiple encapsulations which
provide maximum protection to the oil droplets. They also suggested that
combination of matrices, drying temperature, microcapsule morphology,
and processing time are among the most critical factors governing oxidative
stability of fish oil.
1.4.4 METAL IONS
Most biological and food studies of lipid peroxidation involve transition
metal ions (Fe , Cu , etc.), and it is generally accepted that iron is pivotal
n+
n+
in catalyzing oxidative changes in tissues (Gutteridge & Halliwell, 1990;
Kanner, 1994). It was found that iron concentration in cod muscle is very
low, with an average value of 6 ppm (Vareltzis et al., 2008). “Free” catalytic
iron in the muscle might be generated by the destruction of the heme and
release of iron. However, Undeland et al. (2003) suggested that the “free”
iron has a negligible effect on the oxidation of washed cod muscle system.
LMW iron added at a concentration of 23.2 µM did not induce oxidation of
washed minced cod lipids while hemoglobin at this concentration was very
pro-oxidative (Richards & Hultin, 2000).
Ladikos and Lougovois (1990) suggested that lipid oxidation is enhanced
by metals such as iron, cobalt, and copper which facilitate the transfer of
electrons leading to increased rates of free radical formation. The most
common way that metal ions enter food is via the water used and in some
instances via salt and spices (Taylor, 1987). The form of the metal is as
important as the amount of metal present (Taylor, 1987). Ferrous iron has
been shown to have greater pro-oxidant activity than ferric iron in cooked
uncured meats (Pearson et al., 1977). Low levels of ascorbic acid may