Effect of different irrigation regimes on the quality attributes of monovarietal virgin olive oil from cv. “Cobrançosa”

A. A. Fernandes-Silva,J. B. Gouveia,T. C. Ferreira,P. Vasconcelos,F. J. Villalobos

doi:10.3989/gya.070512

Abstract

The aim of this study was to assess the effect of different irrigation strategies in virgin olive oil (VOO) composition and quality of cv. Cobrancosa, integrated in a protected denomination of origin of “Azeite de Tras-os-Montes” in the Northeast of Portugal. Three irrigation treatments were applied: T2-full irrigation that received a seasonal water equivalent to 100% of estimated crop evapotranspiration (ET c ), T1-continuous deficit irrigation (30% ET c ) and T0- rainfed treatment. Data were collected from two consecutive crop years (2005-2006). Irrigation regimes had a minor effect on standard quality indices (free fatty acids, peroxide value, K 232 and K 270 ) of VOO and in fatty acid composition. Total polyphenols decreased up to treatment T2, and were strongly related to the water stress integral, suggesting that the effect of irrigation on this variable occurs along the crop season and not just during the oil accumulation phase. A strategy of continuous deficit irrigation with only 30% of maximum ETc may have an advantageous effect, as it increased oil yield to more than double that of rainfed conditions while VOO quality was similar.

Highlights

Since time immemorial virgin olive oil (VOO) has been considered an essential ingredient of Mediterranean diet because of its special characteristics
That the quality characteristics of extra-virgin olive oils derive from concomitant action of various agronomical factors such as olive variety (Vinha et al, 2005), climatic conditions during growth (Mousa et al, 1996), degree of maturation (Bonoli et al, 2004) and agronomic practices related to irrigation management (Tovar et al, 2002; Servilli, et al, 2007; Gómez-Rico et al, 2009)
The aim of this study was to evaluate the effect of different irrigation strategies in VOO saponifiable and unsaponifiable composition and VOO quality of a Portuguese cultivar, cv

Summary

Introduction

Since time immemorial virgin olive oil (VOO) has been considered an essential ingredient of Mediterranean diet because of its special characteristics. The consumption of VOO and table olives has steadily increased, even in countries that do not have such tradition, due to its associated healthy properties, namely its beneficial effect on protection against cardiovascular and neurodegenerative diseases (Pérez-Jiménez et al, 2007), and its potential role in reducing the potential risk of several cancers (Menendez et al, 2006). These beneficial effects are related to the characteristic fatty acid composition and the presence of minor components, such as squalane, phytosterols and antioxidant molecules, such as tocopherols and other phenolic compounds (Owen et al, 2000). VILLALOBOS that the quality characteristics of extra-virgin olive oils derive from concomitant action of various agronomical factors such as olive variety (Vinha et al, 2005), climatic conditions during growth (Mousa et al, 1996), degree of maturation (Bonoli et al, 2004) and agronomic practices related to irrigation management (Tovar et al, 2002; Servilli, et al, 2007; Gómez-Rico et al, 2009)

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Conclusion