IRRIGATION REGIMES AND GROWING AREA EFFECTS ON CHÉTOUI OLIVE OIL QUALITY

Abstract

ABSTRACT The effects of both the irrigation regimes (50% evapotranspiration [ETc], 75% ETc and 100% ETc) and the growing area on the quality of Chétoui virgin olive oil obtained from an intensively managed orchard in a semi-arid and arid area with a Mediterranean climate in Tunisia were evaluated. The quality, determined using the usual parameters for virgin olive oils (acidity and peroxide value), was slightly affected by irrigation in the north, and more significatively in the south. Irrigation positively affected fruit weight (86.1% of variability) in all cases. Growing area exhibited a more important effect on the fatty acid profile (96.3% of variability) than the irrigation management (1.8% of variability). Total phenols and bitterness intensity strongly differed: the different irrigation regimes applied in the north had no effect on the bitterness of Chétoui virgin olive oils, whereas the same water management applied in the south caused a marked decrease in both bitterness category and total phenols. Aroma compounds exhibited different behavior according to growing area and irrigation management. PRACTICAL APPLICATIONS This research is strongly oriented to the agronomic application. The obtained results can orient an agronomist to the suitable irrigation management, applied on the appropriate growing area, in order to obtain a good yield and a balanced composition of the olive oil using the least amount of water.