Abstract:
Olive cultivars Bladi and Arbequina were collected
and their oil was extracted (cold
press). Oil was refined under bleaching and deodori
zation conditions for 30 minutes at
55-50°C and their property was compared with the vir
gin olive oil. Virgin and refined oils
of the cultivars were processed by fryer heating at
180°C (intervals of 0, 1, 2, 4, and 8
hours) and indexes of fatty acid, free fatty acid,
peroxide, thiobarbituric acid, polar
compounds, conjugated dienes and trienes, Rancimat,
color, total polyphenol, tocopherol,
chlorophyll and carotenoid were compared. Results s
howed that these oils mainly
contained oleic (48.69-60.18%), palmitic (18.31-27.
02%), linoleic (7.54-18.58%),
palmitoleic (3.9-3.08%), stearic (1.78-2.53%), and
linoleic acids (1.87-0.22%). According
to the results, it was recommended to refine virgin
olive oil by mild bleaching and
deodorization to save bioactive compounds. Due to t
he heating condition, the relative
amounts of unsaturated fatty acids (22.37-50.6%), p
olyphenols, tocopherols, chlorophyll,
carotenoid and oxidative stability decreased and th
e relative amounts of saturated fatty
acids (14.2-17.1%), acidity, peroxide, conjugated d
ienes and trienes, polar compounds,
and thiobarbituric acid increased significantly, bu
t the colorant initially decreased and
then increased (P< 0.05). Due to polar compounds, f
or frying process, mild refined oil was
better than extra virgin oil.
Keywords:
Bioactive compounds, Bleaching and deodorization,
Olive cultivars,
Stability
indexes, Virgin olive oil.