Study of the Quality Parameters and the Antioxidant Capacity for the FTIR-Chemometric Differentiation of Pistacia Vera Oils.

Lydia Valasi,Maria Georgiadou,Dimitra Arvanitaki,Angeliki Mitropoulou,Christos S Pappas

doi:10.3390/molecules25071614

Abstract

The aim of this work was to characterize the pistachio oil of the Greek variety, “Aegina”, evaluate its various quality indices, and investigate the potential use of FTIR as a tool to discriminate different oil qualities. For this purpose, the antioxidant capacity, the tocopherol content and the oxidation and degradation of fatty acids, as described by k, Δk, R-values, and free acidity were evaluated using 45 samples from eight different areas of production and two subsequent years of harvesting. The antioxidant capacity was estimated using 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid diammonium salt (ABTS) and 2,2-diphenyl-1-(2,4,6-trinitrophenyl)hydrazine (DPPH) assays, and the tocopherol content was quantified through HPLC analysis. FTIR spectra were recorded for all samples and multivariate analysis was applied. The results showed significant differences between the oil samples of different harvesting years, which were successfully discriminated by a representative FTIR spectral region based on R-value, total antioxidant capacity, and scavenging capacity, through ABTS. A similar approach could not be confirmed for the other quality parameters, such as the free acidity and the tocopherol content. This research highlighted the possibility of developing a simple, rapid, economic, and environment friendly method for the discrimination of pistachio oils according to their quality profile, through FTIR spectroscopy and multivariate analysis.

Highlights

Pistacia, a genus of the Anacardiaceae family, includes at least eleven species, among them Pistacia vera L. is the only edible commercial species [1]
The results showed significant differences between the oil samples of different harvesting years, which were successfully discriminated by a representative Fourier transform infrared (FTIR) spectral region based on R-value, total antioxidant capacity, and scavenging capacity, through ABTS
A similar approach could not be confirmed for the other quality parameters, such as the free acidity and the tocopherol content

Summary

Introduction

A genus of the Anacardiaceae family, includes at least eleven species, among them Pistacia vera L. is the only edible commercial species [1]. The pistachio nut is an important agricultural commodity for a number of countries. Iran, United States, Turkey, Syria, Greece, Italy, and Spain are the main pistachio producers [2]. Pistachio nut can be considered to be a functional food, and has recently been ranked among the first 50 food products with the highest antioxidant potential [3]. The. Dietary Guidelines recommend that consuming nuts (almonds, hazelnuts, walnuts, pistachios, pecans, and peanuts) as a part of a daily diet has a beneficial effect on human health [4]. The pistachio (Pistacia vera L.) oil content ranges from 50% to Molecules 2020, 25, 1614; doi:10.3390/molecules25071614 www.mdpi.com/journal/molecules

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