Influence of olive fly (Bactrocera oleae) on the phenolic composition and antioxidant activity of four Algerian olive cultivars

The olive fly, Bactrocera oleae (Rossi) (Diptera: Tephritidae) is one of the main pests of the olive tree which can affect the production and quality of the products. The phenolic compounds are important biological constituents and play a significant role in the susceptibility or tolerance of a cultivar to fly attack. This work aimed to study the influence of the attack of this pest on the phenolic composition and the antioxidant activity of four Algerian olive cultivars. The weight, maturity index, attack rate, phenolic profile, and antioxidant activities (Reducing power, ABTS assay and Chelating capacity) of the olives of the cultivars were determined. Phenolic compounds were determined by HPLC. The results showed that the size of the fruit (weight) was significantly correlated with the attack (r = 0.91). The phenolic composition was significantly affected; the total losses of polyphenols were maximal in infested olive samples of Ferkani (52.64%) and Souidi (42.71%). Consequently, the antioxidant activities evaluated by different methods decreased significantly, the losses reached 86%. The values of the Relative Antioxidant Capacity Index (RACI), which represent the average scores of the antioxidant activities of each sample, showed that the varieties have different sensitivities. The lowest scores were recorded by attacked olives. The results confirmed the importance of healthy fruit in obtaining products with a high level of phenolic compounds.