Food Lipids: Chemistry, Nutrition, and Biotechnology

as shown in Figure 6. List et al. [42] reported a highly significant correlation between
p-AnV and flavor acceptability scores of salad oils processed from undamaged
soybeans.
4. TOTOX Value
The p-AnV is often used in the industry in conjunction with PV to calculate the socalled
total oxidation or TOTOX value:
TOTOX value = 2PV � p-AnV
The TOTOX value is often considered to have the advantage of combining evidence
about the past history of an oil (as reflected in the p-AnV) with its present state (as
evidenced in the PV). Therefore, determination of TOTOX value has been carried
out extensively to estimate oxidative deterioration of food lipids [43]. However,
despite its practical advantages, TOTOX value does not have any sound scientific
basis because it combines variables with different dimensions. Recently, Wanasundara
and Shahidi [44] defined TOTOXTBA as 2PV � TBA since determination of p-
AnV may not be always feasible.
5. Carbonyls
An alternative approach for monitoring the extent of lipid oxidation in fats and oils
is to measure the total or individual volatile carbonyl compounds formed from degradation
of hydroperoxides. One of the more reliable methods for total carbonyl
analysis is based on the absorbance of the quinoidal ion, a derivative of aldehydes
Figure 6 Possible reactions between p-anisidine reagent and malonaldehyde.
Copyright 2002 by Marcel Dekker, Inc. All Rights Reserved.