Page 227 - Natural Antioxidants, Applications in Foods of Animal Origin

206 Natural Antioxidants: Applications in Foods of Animal Origin
VetBooks.ir 6.1.2 RELATIVE OXIDATIVE STABILITY OF MEAT AND FISH

LIPIDS

Given that all other processing variables are equal, the presence (not neces-
sarily the concentration) of unsaturated fatty acids drives lipid oxidation.
Figure 6.2 shows a comparison of fatty acid profiles for beef, chicken, and
salmon, as the fatty acid profile favors PUFAs the susceptibility to oxida-
tion increases and shelf-life decreases. Throughout this chapter data will be
presented showing the rate of oxidation in value-added meat products also
depends on product form, processing methods, packaging techniques, and
storage conditions.

Rate of Oxidatioin of Unsaturated Fatty Acids Relative to Stearic Acid
3000
0:
.Sl 2500
'o!
"t:l
8 2000
~ 1500
~
-~ 1000
~ 500
0
18:0, Sterle Acid 18:1 Oleic Acid 18:2, Linoleic Acid 18:3, Linolenic Acid
Types of Fatty Acids
FIGURE 6.2 The susceptibility of a fatty acid to oxidation increases as unsaturation
increases. When all other factors are equal, unsaturation dictates the differences in expected
shelf life between value added products formulated from lamb, beef, pork, poultry or fish.
Modified from http://www.public.iastate.edu/~duahn/teaching/Lipid%20oxidation/Lipid%20
Oxidation%20An%20Overview.pdf

6.1.3 SELECTION CRITERIA AND SAMPLE PREPARATION

Various analytical methods are available for measuring the extent of lipid
oxidation. Regardless of the method selected, the more criteria, listed below,
that are met, the more valuable the information will be.

1. The method is sensitive, accurate, and precise. The method’s limit of
quantification (LOQ) distinguishes fresh from oxidized products and
less oxidized products from more oxidized products.
2. Data from the analysis are reproducible.