Treated Unconventional Waters Combined with Different Irrigation Strategies Affect 1H NMR Metabolic Profile of a Monovarietal Extra Virgin Olive Oil

Federica Angilè,Gabriele Caponio,Salvatore Camposeo,Giuseppe Lopriore,Laura Del Coco,Francesco Paolo Fanizzi,Chiara Roberta Girelli,Gaetano Alessandro Vivaldi

doi:10.3390/su14031592

Abstract

The agricultural sector is facing a decrease in water supply and water quality at a global level and this is a problem that strictly affects all the Mediterranean olive growing areas. The aim of this work was to evaluate, for the first time, by NMR Spectroscopy and multivariate data analysis the metabolic profiling of the oils produced under different irrigation schemes. Arbosana olive oils were obtained from the use of saline reclaimed water (RW) and treated municipal wastewater (DW), combined with: full irrigation (FI) and regulated deficit irrigation (RDI). The results show a higher relative content of saturated fatty acids in EVOOs obtained from RDI strategy, regardless of the water source. Moreover, an increase in unsaturated fatty acids, a ω6/ω3 ratio content was observed in EVOOs obtained from RW when compared with DW water. Furthermore, the RW–RDI showed an increase in secoiridoid derivatives and hydroperoxides with respect to DW–RDI. A sustainable irrigation management, by combining a deficit irrigation strategy and saline reclaimed water source, could be crucial in order to overcome the problem of water scarcity and to guarantee the olive oil nutraceutical properties. The 1H NMR-based metabolomic approach proved a powerful and versatile tool for this specific investigation.

Highlights

Availability of water for irrigation is a key factor for the agricultural sector of the Apulia region (Southern Italy), this land being characterized by a Mediterranean climate with hot, dry summers and mild, wet winters [2,3]
A preliminary unsupervised PCA was performed on the NMR data set, related to the oil major components (BUCKET-1, obtained using 1 H ZG spectra), with the aim to observe the natural grouping of the data (Figure 1a)
The PCA model revealed a degree of separation between the two irrigation strategies (RDI and full irrigation (FI))

Summary

Introduction

Climate change is considered one of the major concerns for society, as reported by the Global Risk Report 2020 [1]. The duration, maximal temperature and global intensity of heat waves together with droughts have strongly increased over the past 30 years [2], representing the greatest risk. The economic loss, due to water scarcity, involves several productive areas of the agriculture sector. In the Italian context, a EUR 2 billion loss was estimated for agricultural farms [2]. Availability of water for irrigation is a key factor for the agricultural sector of the Apulia region (Southern Italy), this land being characterized by a Mediterranean climate with hot, dry summers and mild, wet winters [2,3]. In the Apulia region, a high irrigation water volume is required to supply

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