Concomitant Use of Fourier Transform Infrared Attenuated Total Reflectance Spectroscopy and Chemometrics for Quantification of Multiple Adulterants in Roasted and Ground Coffee

Nádia Reis,Adriana S Franca,Leandro S Oliveira

doi:10.1155/2016/4974173

Abstract

This paper proposed the joint use of Fourier Transform Infrared Attenuated Total Reflectance Spectroscopy (FTIR-ATR) and Partial Least Square (PLS) regression for the simultaneous quantification of four adulterants (coffee husks, spent coffee grounds, barley, and corn) in roasted and ground coffee. Roasted coffee samples were intentionally blended with the adulterants, at adulteration levels ranging from 0.5 to 66% w/w. A robust methodology was implemented in which the identification of outliers was carried out. High correlation coefficients (0.99 for both calibration and validation) coupled with low degrees of error (0.69% for calibration; 2.00% for validation) confirmed that FTIR-ATR can be a valuable analytical tool for quantification of adulteration in roasted and ground coffee. This method is simple, fast, and reliable for the proposed purpose.

Highlights

New and challenging risks, such as adulteration, have emerged as food supply chains become increasingly global and complex, fraud in the food sector has been an issue since ancient times
We have shown that Diffuse Reflectance Fourier Transform Infrared Spectroscopy (DRIFTS) is suitable for identification, discrimination, and quantification of adulterants in roasted and ground coffee [4, 9, 10]
RMSEP values were Standard Normal Variates (SNV) followed by mean centering. This model was built with 8 latent variables (LV) that together explained 93.5%

Summary

Introduction

New and challenging risks, such as adulteration, have emerged as food supply chains become increasingly global and complex, fraud in the food sector has been an issue since ancient times. Food adulteration tends to be economically motivated and is achieved through addition, substitution, or removal of food ingredients. It is an issue that concerns consumers, but producers and distributors as well [1]. Coffee is one of the most valuable and most commonly consumed beverages in the world. Impurities and adulterants are the most common concern. Any lowcost material of biological origin could be used as a potential adulterant in coffee [2]. Roasted and ground coffee presents physical characteristics (particle size, texture, and color) that are reproduced by roasting and grinding a variety of biological materials (cereals, seeds, parchments, etc.)

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Results

Conclusion