Oil content, phenolic profiling and antioxidant potential of Tunisian olive drupes.
BACKGROUND
The aim of this work was to investigate the effect of the maturation process of the olive fruit on oil content, phenolic profile and antioxidant activity of four Tunisian cultivars (Zelmati, Chemchali, Chemlali and Chétoui).


RESULTS
The average oil content of the studied varieties ranged between 17.50% and 20.25% at the first stage of maturation and from 30.20% to 35% in the last harvest. Qualitative and quantitative analysis of phenolic compounds were carried out using HPLC and LC-MS/MS. Twenty-six biophenolic compounds were identified. In all samples, hydroxytyrosol and oleuropein were the major compounds identified while rutin and luteolin 7-O-glucoside were the two main flavonoids. The total phenolic content varied from 3.46 to 4.30 g kg(-1) at the first stage of maturation and from 8.71 to 11.52 g kg(-1) of fruit fresh weight at the last maturation phase. Total flavonoid content reached 432.80 mg kg(-1). The antioxidant activity of the extract was evaluated by DPPH and ABTS assays. The IC(50) values of the olive extracts ranged from 2.69 to 10.96 microg L(-1) and from 2.15 to 3.03 mmol L(-1) trolox equivalent at the last stage of maturation.


CONCLUSIONS
A relationship between the changes in phenolic content and the physicochemical changes in Tunisian olive fruit during maturation was established. These findings could be used for controlling the production processes and correlating the oil sensorial characteristics to the polyphenolic pattern.
Bouaziz
Mohamed
M
Laboratoire des Bioprocédés Environementaux, Pôle d'Excellence Régionale AUF, (PER-LBPE) Centre de Biotechnologie de Sfax, Sfax, Tunisia. mohamed.bouaziz@cbs.rnrt.tn
Jemai
Hedya
H
Khabou
Wahid
W
Sayadi
Sami
S
D000975:Antioxidants / Q000032:analysis / Q000494:pharmacology*; D052160:Benzothiazoles; D001713:Biphenyl Compounds; D005419:Flavonoids / Q000032:analysis / Q000494:pharmacology*; D005638:Fruit / Q000737:chemistry* / Q000235:genetics; D005838:Genotype; D020128:Inhibitory Concentration 50; D031658:Olea / Q000737:chemistry* / Q000235:genetics; D010636:Phenols / Q000032:analysis / Q000494:pharmacology*; D010851:Picrates; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D010938:Plant Oils / Q000032:analysis*; D059808:Polyphenols; D013451:Sulfonic Acids; D013844:Thiazoles
D000975:Antioxidants; D052160:Benzothiazoles; D001713:Biphenyl Compounds; D005419:Flavonoids; D010636:Phenols; D010851:Picrates; D010936:Plant Extracts; D010938:Plant Oils; D059808:Polyphenols; D013451:Sulfonic Acids; D013844:Thiazoles; C002502:2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid; C004931:1,1-diphenyl-2-picrylhydrazyl