Articles
Olive fruits enriched in phenolics by pre-harvest abscisic acid treatment
Article number
1297_61
Pages
463 – 470
Language
English
Abstract
The health attributes associated with olive fruits are partially due to the presence of the antioxidant characteristics of polyphenols.
In addition, phenolic compounds also contribute to the oxidative stability of olive polyunsaturated fatty acids.
The aim of this research was to study the effect of abscisic acid pre-harvest treatment on the phenolic composition of olive fruits.
To that end we applied two abscisic acid doses (50 and 100 mg L‑1) on two olive tree cultivars, Arbequina and Picual. The total phenol content, the 2,2-diphenil 1-picrylhydazyl (DPPH) activity, contents of oleuropein, hydroxytyrosol and phenolic acids (caffeic and chlorogenic acids) were considered at two different days of harvesting (day 3 and 6 after treatment). Although the results depended on the cultivar and the day of harvesting, the treatment resulted in a general increase of antioxidant content.
The treatment with 50 mg L‑1 of abscisic acid resulted in higher total phenol content but significant decrease in the DPPH activity.
In contrast, olives treated with 100 mg L‑1 abscisic acid resulted, in general, in higher total phenol content, DPPH activity and contents of oleuropein, hydroxytyrosol and phenolic acids as compared with controls.
The best values of total phenol content and of the half maximal inhibitory concentration (IC50) were obtained for treated Picual olives (727.75 mg gallic kg‑1 and 889.72 µg mL, respectively) whereas the highest values of oleuropein and hydroxytyrosol were found for treated Arbequina olives (508.94 and 559.67 mg kg‑1, respectively). Particularly, values ranged from 7.26 mg kg‑1 for caffeic acid to 92.38 mg kg‑1 for chlorogenic acid.
Exogenous abscisic acid applied to olive trees is a promising agronomic practice to obtain olives enriched in antioxidants.
In addition, phenolic compounds also contribute to the oxidative stability of olive polyunsaturated fatty acids.
The aim of this research was to study the effect of abscisic acid pre-harvest treatment on the phenolic composition of olive fruits.
To that end we applied two abscisic acid doses (50 and 100 mg L‑1) on two olive tree cultivars, Arbequina and Picual. The total phenol content, the 2,2-diphenil 1-picrylhydazyl (DPPH) activity, contents of oleuropein, hydroxytyrosol and phenolic acids (caffeic and chlorogenic acids) were considered at two different days of harvesting (day 3 and 6 after treatment). Although the results depended on the cultivar and the day of harvesting, the treatment resulted in a general increase of antioxidant content.
The treatment with 50 mg L‑1 of abscisic acid resulted in higher total phenol content but significant decrease in the DPPH activity.
In contrast, olives treated with 100 mg L‑1 abscisic acid resulted, in general, in higher total phenol content, DPPH activity and contents of oleuropein, hydroxytyrosol and phenolic acids as compared with controls.
The best values of total phenol content and of the half maximal inhibitory concentration (IC50) were obtained for treated Picual olives (727.75 mg gallic kg‑1 and 889.72 µg mL, respectively) whereas the highest values of oleuropein and hydroxytyrosol were found for treated Arbequina olives (508.94 and 559.67 mg kg‑1, respectively). Particularly, values ranged from 7.26 mg kg‑1 for caffeic acid to 92.38 mg kg‑1 for chlorogenic acid.
Exogenous abscisic acid applied to olive trees is a promising agronomic practice to obtain olives enriched in antioxidants.
Authors
M.C. Gomez-Jimenez, G.P. Blanch, G. Flores, M.L. Ruiz Del Castillo
Keywords
antioxidant, functional, elicitors, fruit quality, pre-harvest treatment
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