Page 242 - Natural Antioxidants, Applications in Foods of Animal Origin

Methods and Their Applications for Measuring 221
VetBooks.ir of a basic solution of reagent grade MDA tetrabutylammonium added to an

acidic solution of TBA. The concentration can be determined from absor-
bance at 532 nm. Beer’s law provides a linear relationship between absor-
bance and concentration of TBARS via the linear equation y = mx + b.
From the standard curve y = mx + b
y is the absorbance of the test sample,
m is the slope from calibration with reagent grade MDA,
x is the concentration (mg mL ) of test sample (unknown),
–1
b is the “y” intercept from calibration with reagent grade MDA.

Based on mg mL multiplied by the volume of the extract (mL), multi-
–1
plied again by any dilution factors, divided by the weight of the meat sample,
and multiplied 1000 to express data as mg TBARS (as MDA) kg of sample.
-1
To express in µmoles per unit weight convert it by using 72 µg per µmole.
The LOQ using in this method is 1.0 µmole or 72 µgrams. This level of
sensitivity adequately discriminates between fresh and degrees of oxidiza-
tion between test samples during shelf-life studies.
Acceptable values for TBARS meat type (beef, pork, poultry, and fish),
formulation, and process specific. Table 6.4 shows the variation in accept-
able levels of TBARS for a few types of value-added meat products.

TABLE 6.4 Acceptable Values for TBARS Varies from Product to Product. Adapted from
Handbook for Meat Chemists, Edward Koniecko.
Average acceptable TBARS values for selected meat products
–1
TBARS expressed as mg MDA 1000 g of meat
Meat product Avg. TBARS
Beef bologna 0.222
Fresh Italian sausage 0.195
Smoked sausage 0.273
Beef weiner 0.197
Hard salami 0.429
Chicken roll 1.100
Boiled ham 0.105
Pepperoni 0.343
Fresh sausage patties 0.280
Bacon, sliced vacuum packaged 0.052