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

Abstract

RESUMEN Efecto de diferentes regímenes de riego sobre los índices de calidad del aceite de oliva de cv. "Co brançosa"El objetivo del estudio fue evaluar el efecto de distintas estrategias de riego en la composición y la calidad del aceite de oliva virgen de cv. Cobrançosa, integrado en una denominación de origen protegida de «Azeite de Trás-osMontes», en el noreste de Portugal. Tres tratamientos de riego fueron aplicados: T2-riego total, el olivo recibió el equivalente estacional de agua al 100% de la evapotranspiración estimada del cultivo (ETc), T1-riego continuo deficitario (30% de la ETc) y el tratamiento T0-de secano. Los datos fueron recolectados a partir de dos campañas agrícolas consecutivas (2005)(2006). Los regímenes de riego tuvieron un efecto menor en los índices de calidad estándar (ácidos grasos libres, índice de peróxidos, K 232 y K 270 ) del aceite de oliva y en la composición de ácidos grasos. Los polifenoles totales disminuyeron hasta el tratamiento T2, y se relacionaron fuertemente con el integral de estrés hídrico, lo que sugiere que el efecto del riego sobre esta variable se produce a lo largo de la temporada de cultivo y no sólo durante la fase de acumulación de aceite. Una estrategia de riego deficitario continuo con sólo 30% de la ETc máxima puede tener un efecto beneficioso, ya que aumentó la producción de aceite de oliva a más del doble que en condiciones de secano, mientras que la calidad del aceite de oliva fue similar. PALABRAS CLAVE: Aceite de oliva virgen -cv. Cobrançosa -Índices de calidad -Riego. ABSTRACT Effect of different irrigation regimes on the quality attributes of monovarietal virgin olive oil of cv. "Cobrançosa"The aim of this study was to assess the effect of different irrigation strategies in virgin olive oil (VOO) composition and quality of cv. Cobrançosa, integrated in a protected denomination of origin of "Azeite de Trás-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.

Virgin olive oil quality of hedgerow ‘Arbequina’ olive trees under deficit irrigation

“…Many studies report a lack of influence of irrigation supplies on VOO quality . However, an increase in PV or K 232 with increasing irrigation has been reported widely . This effect was not observed for all of the seasons studied.…”

Sensory analysis and volatile compounds of olive oil (cv. Cobrançosa) from different irrigation regimes

“…In both years, the characteristic pungent and bitter attributes are more pronounced in olive oils from T0 and T1, which had higher polyphenolic concentrations (Fernandes-Silva et al, 2013). This relationship is more prominent in 2005, the year with the higher stress level (Fernandes-Silva et al, 2010).…”

“…This behavior has been observed for totals polyphenols in other studies for the cv. "Cornicabra" (Moriana et al, 2007) and cv "Cobrançosa" (Fernandes-Silva et al, 2013). In Turkey, Kiralan et al (2012) reported differences in the composition of olive oil volatile compounds of the cultivar "Gemlik" according to the geographical area with respect to the variability of climatic conditions.…”

“…A univariate analysis was applied to sensory attribute intensities and, to concentrations of polyphenols (Fernandes-Silva, et al, 2013) and the volatile compounds described in Table 1. Some correlations were observed among the considered variables ( Table 2).…”

The Selenium Supplementation Influences Olive Tree Production and Oil Stability Against Oxidation and Can Alleviate the Water Deficiency Effects

“…However, the higher levels of phenols in EVOO from Se-treated trees may be due to a secondary effect caused by the inhibition of enzymatic phenol oxidation by strong antioxidant-active Se compounds (D’Amato et al, 2014). Since the high phenol content in EVOO could be considered a positive aspect because the higher the phenol content, the greater the oxidative stability, the increase of phenol content obtained from the DS and T treatments resulted in an increase of EVOO oxidative stability (Tovar et al, 2002; Ayton et al, 2007; Gouveia et al, 2013). …”