Page 35 - Natural Antioxidants, Applications in Foods of Animal Origin
P. 35

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
   30   31   32   33   34   35   36   37   38   39   40