Food Chemistry

646 14 Edible Fats and Oils

Table 14.6.Olive oils: concentrations of the minor constituents

Type Alcoholsa Waxesa,b Sitosterola Erythrodiola Erythrodiol +
free esterified Uvaol (%)c

Extra viergeoil 67 40 914 219 13 1
“Lampante” oil, raw 84 292 945 877 10 0. 6
“Lampante” oil, refined 44 180 692 544 8 0. 8
Extraction oil, raw 725 3294 1234 2702 283 13. 5
Extraction oil, refined 75 3277 659 2624 116 5. 6
aValues in mg/kg.
bSum of the wax esters C 40 –C 46.
cPercentage of the sum of sterols and triterpene dialcohols.

(14.1)

The aroma of natural oils is of special interest.
The most important aroma substances of two
extra viergeolive oils with different aromas are
shown in Table 14.7. In oil I, green, fruity, and
fatty notes are predominant while in oil II, the
compounds with a green odor are concealed by
an aroma substance with a “blackcurrant” odor,
possibly due to a special variety of the olives.
The compound involved is the extremely inten-
sive odorant 4-methoxy-2-methyl-2-butanethiol

Table 14.7.Important aroma substances of twoextra viergeolive oilsa

Oil I Oil II

Aroma substance Aroma quality C Ax CAx

Isobutyric acid ethyl ester Fruity 4 .9 7 14 19
2-Methylbutyric acid ethyl ester Fruity 3 .9 5 14 19
Cyclohexanoic acid ethyl ester Fruity 1. 64. 24. 311
(Z)-3-Hexenal Green 33 12 53 19
(Z)-2-Nonenal Green, fatty 9 15 10 17
Acetic acid Like vinegar 10 , 490 10 6680 6
4-Methoxy-2-methyl-2-butanethiol Like blackcurrants n.d. 1. 840
aOil I is from Italy, oil II from Spain; concentration C is in μg/kg and the aroma value Axis calculated on the

basis of the odor thresholds (retronasal) in an oil; n.d.: not detectable (C< 0 .05 μg/kg).

(cf. Table 5.34), which has the highest aroma

value of all the volatile compounds in oil II

(Table 14.7).

The fatty acid composition of tea seed oil is very

similar to that of olive oil. However, these two oils

can be differentiated by using theFitelsonTest

(cf. Table 14.21).

14.3.2.1.2 Palm Oil

This oil is obtained from oil palm, the utiliza-

tion of which is constantly increasing (cf. Ta-

ble 14.1). Palm plantations are found primarily in

western Malaysia and Indonesia (cf. Table 14.0).

The fruits provide two different oils, the first from

the pulp and the second from the seeds.

Oil Production.The fruit cluster, which contains

about 3000–6000 fruits, is first steam-treated to

inactivate the high lipase activity and to separate

the pulp from the seed. The oil is recovered

by pressing the disintegrated pulp. The crude