Abstract:
J. Agr. Sci. Tech. (2016) Vol. 18: 79-91
79
Bioactive Compounds and Antioxidant Activities of T
hyme-
Enriched Refined Corn Oil
I. Jabri Karoui
1,2
∗
, K. Msaada
1
, M. Abderrabba
2
, and B. Marzouk
1
ABSTRACT
This study was designed to examine bioactive compou
nds of the thyme-enriched corn oil and
to determine the antioxidant activity of its methan
olic extract. Volatile compounds composition
was investigated by Gas Chromatography-Mass Spectro
metry (GC-MS), whereas phenolic
compounds analysis was performed by Reversed-Phase
High-Performance Liquid
Chromatography (RP-HPLC). Antioxidant activities of
the flavoured oil methanolic extract
were evaluated using DPPH radical scavenging,
β
-carotene-linoleic acid bleaching, reducing
power and total antioxidant assays. Flavoured oil m
ajor volatiles were
p
-cymene (26.47%
),
α
-
thujene (24.06%) and
γ
-terpinene (14.30%). Its methanolic extract had hig
her Total Phenol
Contents (TPCs) (53.99 mg 100 g
-1
) than that of the crude oil (23.63 mg 100 g
-1
). Thymol was
the main phenolic compound in the flavoured oil (55
.84%
). Flavoured oil methanolic extract
showed higher total antioxidant activity (185.22 mg
Gallic Acid Equivalent (GAE) 100 g
-1
) than
that of the crude one (100.66 mg GAE 100 g
-1
). In
β
-carotene-linoleic acid bleaching and DPPH
radical scavenging assays, flavoured oil methanolic
extract showed higher activities than that
of the crude oil based on
IC
50
values. Flavoured and crude oils were characterized
by a close
CE
50
values (1.81 and 1.85 mg mL
-1
, respectively). Antioxidant activities of the thym
e-enriched
oil were mainly due to the presence of phenolic com
pounds such as thymol and hydrocarbons
such as
γ
-terpinene and
p
- cymene. The thyme-enriched oil could be considere
d as a new and
natural source of antioxidant.
Keywords:
Antioxidant activity, Corn oil, Essential oil, Pol
yphenols,
Thymus capitatus
.
