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Food Lipids: Chemistry, Nutrition, and Biotechnology

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Table 4 Volatile Compounds Formed from Methyl Oleate Hydroperoxides<br />

Compound<br />

Heptane<br />

Octane<br />

Heptanal<br />

1-Heptanol<br />

Octanol<br />

Methyl heptanoate<br />

1-octanol<br />

Nonanal<br />

Methyl octanoate<br />

2-Nonenal<br />

Decenal<br />

Methyl nonanoate<br />

2-Decenal<br />

2-Undecenal<br />

Methyl 8-oxooctanoate<br />

Methyl 9-oxononanoate<br />

Methyl 10-oxodecanoate<br />

Methyl 10-oxo-8-decanoate<br />

Source: Ref. 10.<br />

Autoxidation<br />

(rel. %)<br />

4.4<br />

2.7<br />

0.5<br />

0.4<br />

11<br />

1.5<br />

0.4<br />

15<br />

5.0<br />

0.5<br />

3.9<br />

1.5<br />

5.4<br />

1.7<br />

3.5<br />

15<br />

12<br />

3.4<br />

Table 5 Threshold Values of Compounds Formed<br />

from Oxidized Oils<br />

Compounds Threshold (ppm)<br />

Hydrocarbons<br />

Substituted furans<br />

Vinyl alcohols<br />

1-Alkenes<br />

2-Alkenals<br />

Alkanals<br />

trans,trans-2,4-Alkadienals<br />

Isolated alkadienals<br />

Isolated cis-alkenals<br />

trans,cis-Alkadienals<br />

Vinyl ketones<br />

Source: Ref. 10.<br />

90–2150<br />

2–27<br />

0.5–3<br />

0.02–9<br />

0.04–2.5<br />

0.04–1<br />

0.04–0.3<br />

0.002–0.3<br />

0.0003–0.1<br />

0.002–0.006<br />

0.00002–0.007<br />

Photosensitized<br />

oxidation<br />

(rel. %) Origin<br />

4.6<br />

10<br />

0.5<br />

0.4<br />

3.8<br />

4.9<br />

1.0<br />

10<br />

9.7<br />

0.7<br />

2.0<br />

0.8<br />

12<br />

7.1<br />

3.0<br />

11<br />

1.7<br />

5.0<br />

11-OOH<br />

10-OOH<br />

?<br />

11-OOH<br />

11-OOH<br />

8-OOH<br />

10-OOH<br />

9/10-OOH<br />

9-OOH<br />

?<br />

8-OOH<br />

?<br />

9-OOH<br />

8-OOH<br />

8-OOH<br />

9/10-OOH<br />

11-OOH<br />

10-OOH<br />

during oxidation. Most of these are responsible for the off-flavor in oxidized edible<br />

oils. However, the aliphatic carbonyl compounds, such as alkanals, trans,trans-2,4alkadienals,<br />

isolated alkadienals, isolated cis-alkenals, trans,cis-2,4-alkadienals, <strong>and</strong><br />

vinyl ketones, have the lowest threshold values as shown in Table 5. Frankel [10]<br />

reported that the significant compounds responsible for flavor are trans,cis-2,4-de-<br />

Copyright 2002 by Marcel Dekker, Inc. All Rights Reserved.

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