Effect of Water Supplementation on Oxidant/Antioxidant Activities and Total Phenol Content in Growing Olives of the Morisca and Manzanilla Varieties

The objective of this work was to analyse, using a time series analysis, the effect of water regime for two cultivars at three stages of ripeness, during three consecutive years. Fruit and oil yield; O-2(-) production and NADH oxidation activities; polyphenol oxidase (PPO), superoxide dismutase (SOD) and peroxidase (POX) activities; total phenols, flavonoid and phenylpropanoid glycoside content; and total antioxidant capacity (FRAP) were determined. All these parameters were found to depend on variety, irrigation and year. The results showed that the fruit and oil yields were strongly dependent on both irrigation and variety. The DW/FW ratio was practically constant during ripening, with small variety-dependent changes due to irrigation. Total amino acid and protein contents increased with ripening, with a close dependence on variety but not on irrigation. The SOD and PDX activities appeared closely related, and related to the NADH oxidation and the amount of O-2(-). The evolution of phenols and FRAP during ripening was complementary to that of NADH oxidation, O-2(-) production as well as SOD and PDX activities. The determining factors of the SOD, PDX and PPO activities were the variety and the ripening; the determining factor of the yield, ROS production, total phenols and antioxidant capacity was the water regime. Inverse correlations were observed between maximum temperature and total phenols (-0.869), total flavonoids (-0.823), total PPGs (-0.801) and FRAP (-0.829); and between DW/FW and irrigation (-0.483). The remaining significant correlations were positive.

Automated summary

This study used time series analysis to analyze the effect of water regime on two cultivars at different stages of ripeness over three consecutive years. The results showed that water regime, variety, and year all had significant effects on fruit and oil yield, as well as other related parameters.