Discrimination and Quantification of Aflatoxins in Pistachia vera Seeds Using FTIR-DRIFT Spectroscopy after their Treatment by Greek Medicinal and Aromatic Plants Extracts

Abstract

A method for detection and quantitative determination of aflatoxins (AFs) produced by Aspergillus flavus in Pistachia vera seeds (pistachio) using Fourier transform infrared spectroscopy, coupled with Diffuse Reflectance Infrared Fourier Transform Spectroscopy (FTIR-DRIFT) is examined in this study. Greek medicinal and aromatic plant extracts with established bioactivity against A. flavus AFs production were used as treatments on pistachio seeds. Classes were analyzed using discriminate analysis algorithm, and distance values were calculated in Mahalanobis distance units. Strong absorptions were detected in the spectral ranges between 1,750 and 1,500 cm^-1, which were different in contaminated and not contaminated samples. The spectra regions that gave matching values less than 50.00 in absolute difference for AFs in pistachio paste samples were 1,705 – 1,575 cm^-1 and 1,350 - 900 cm^-1. Also, the high performance of FTIR as analytical tool for quantitative estimation of AFs was emerged by the Partial Least Square (PLS) regression model that found to fit perfectly the actual concentration values (R²=99.99%) in combination with low levels of errors of calibration, validation and prediction along with a minimum and low-cost sample preparation. The developed methodology presents a great potential of a valuable and reliable technique for composition determination, differentiation and evaluation of AFs in food products. We also aimed to reduce sample preparation in the methodology described and to include pistachio and plant extract matrix in classification demonstrating the suitability of FTIR DRIFT spectroscopic methods for direct AFs detection and quantification in biorefineries and industry.