Page 265 - Natural Antioxidants, Applications in Foods of Animal Origin

244 Natural Antioxidants: Applications in Foods of Animal Origin
VetBooks.ir

TABLE 6.7 Concentration (Usually ppm) can be Calculated Based on the Known Quantity
of an Internal Standard. The Amount of Individual Compounds from Oxidation (e.g.,
Hexanal, Propanal, Nonenal, etc.) may be Calculated or Grouped Together to Calculate Total
Aldehydes).
Internal std. Aldehyde A Aldehyde B Total aldehydes
Peak h, mm 29.0 15.0 20.0
Peak w at 0.5h, mm 3.50 2.50 3.00
2
Peak area, mm 101.5 37.5 60.0 97.5
Peak area ratio 1.00 0.37 0.59 0.96
Concentration (μL) 1.00 0.37 0.59 0.96

Charged particles are accelerated and directed through the mass spec-
trometer by controlling and varying (referred to as scanning potentiometry)
the applied voltage. The electron bombardment produces singly charged
particles; therefore, the path of a charged particle will depend only on mass
or mass charge ratio (m/z). The mass analyzer segregates the charge parti-
cles based on m/z and the detector records the abundance (frequency) of
each m/z.
There is not just one single pathway for fatty acid oxidation, the types
and concentration of secondary oxidation products produced are differed
and concentrations of each can vary. In addition, the type of meat (beef,
pork, poultry, and fish) and processing conditions (cooking method, drying,
aging, fermenting, etc.) will also affect the profile of secondary oxidation
products produced from oxidation.
When samples of oxidized beef were analyzed by GCMS, hexanal,
2-hexanal, 2-nonenal, 2-heptenal, 2-octenal, nonanal, and decanal were
identified (Flores et al., 2013). These “marker compounds” increase over
time to provide information about the rates and extent of lipid oxidation
during shelf-life studies.
The mass spectrograph data in Figure 6.31 show several compounds that
were detected in oxidized ground chicken and the internal standard shown is
a part of the calibration procedure.
The GCMS method was used to monitor the oxidative stability of raw
frozen restructured beef steaks through the distribution chain. The data
from the study would provide information about the stages in distribution
(processing, storage, cooking) would have the most the greatest impact on
lipid oxidation. Restructured steaks are made by comminuting underutilized
beef cuts (chuck, round, sirloin, etc.), then formed into steak or cutlet shapes.