Peanut oil –
Peanut oil is expressed from the seed of Arachis hypogaea L., commonly
known as groundnut, peanut, or earth nut because the seeds develop underground (46).
The seeds are rich in oil (47 to 50%). Peanut oil is rich in oleic and linoleic
acids, typically 43 and 36%, respectively (46).
Crude peanut oil contains 283 mg PS/100 g, which decreases during refining of the
Typical sterol composition of crude peanut oil is shown in Table 3. Unrefined
peanut oil contains PS up to 434 mg/100 g (65).
?-Sitosterol is the major phytosterol of peanut oil, followed by campesterol, ?5-avenasterol
and stigmasterol (34).
?-Sitosterol comprised 64% and campesterol 15% of the total PS. The major
triterpene alcohols included 24-methylene cycloartanol (46%) and cycloartanol (33%)
Coconut oil –
Coconut oil, or copra oil, is an edible
extracted from the kernel or meat of mature coconuts
harvested from the coconut palm (Cocos
nucifera). Coconut oil is an important lauric
oil used by the food and oleo-chemical industries (35, 67). The total sterol content of coconut
oil is about 807 mg/kg and the major PS are ?-sitosterol, ?5-avenasterol, campesterol,
stigmasterol and, with mean values of 46.7%, 26.6%, 8.7% and 12.5% of total
sterols, respectively. (68).
Corn (Maize) oil –
Unlike most other vegetable oils, corn oil is obtained from seeds (kernels)
that contain only 3–5% oil (69).
Almost all commercial corn oil is obtained by pressing and/or hexane extraction
of the oil-rich corn germ (embryo) portion of the corn kernel, and corn oil
could accurately be called ‘corn germ oil’. Commercial corn oil has been
recognized as containing the highest levels of unsaponifiables (1.3–2.3%) of
all the commercial vegetable oils (Table 3) (70).
Corn oil has high phytosterol content ranging between 700- 2210 mg/100 g. The
major phytosterols in corn germ oil are ?-sitosterol > campesterol >
stigmasterol (69, 56). Generally, in corn oil an equal
distribution of the several phytosterols present between the esterified and
free sterol fraction with exception of ?5-avenasterol, which was
only present in the esterified sterol fraction (56).
The pericarp fraction of the immature corn kernel
(30 days after pollination) could potentially be used as a good source of PS.
However, the endosperm part of the immature corn kernel may be a good source of