Discrimination between defective and non-defective roasted coffees by diffuse reflectance infrared Fourier transform spectroscopy

Abstract

a b s t r a c tThe objective of this work was to evaluate the feasibility of employing Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) for discrimination between defective and non-defective coffees after roasting and grinding. Defective (black, immature and sour) and non-defective Arabica coffee beans were submitted to light, medium and dark roasts at 220, 235 and 250 C. Principal Components Analysis of the DRIFTS spectra (normalized or not) and of the first derivatives of the spectra provided separation of the samples into four groups: non-defective, black, dark sour and light sour, with immature beans scattered among the sour samples. Classification models were developed based on Linear Discriminant Analysis and recognition and prediction abilities of these models ranged from 95 to 100%. Such results indicate that DRIFTS presents potential for the development of a fast and reliable analytical methodology for discrimination between defective and non-defective coffee after roasting and grinding.

Characterization of Wastes and Coproducts from the Coffee Industry for Composite Material Production

“…These two peaks, in conjunction with the stretching absorption of carbonyl (C=O) bond at approximately 1740 cm -1 , are associated with the ester group of triglyceride in lipid (fat) (Craig et al 2012), which is present in both samples. A similar observation of the lipid FTIR peaks has been reported for corn-based distillers' grains containing corn oil (Zarrinbakhsh et al 2013).…”

Discrimination between roasted coffee, roasted corn and coffee husks by Diffuse Reflectance Infrared Fourier Transform Spectroscopy

“…Furthermore, DRIFTS was shown to be appropriate for the analysis of roasted coffees, providing satisfactory discrimination between Arabica and Robusta varieties (Kemsley et al, 1995;Suchánek et al, 1996), between regular and decaffeinated coffees (Ribeiro et al, 2010) and between non-defective and defective coffees (Craig, Franca, & Oliveira, 2012b). However, no attempts were reported in the literature on the use of this methodology for the analysis of adulteration of ground and roasted coffee samples.…”

Ochratoxin A, fungal contamination and antioxidant property of defective Arabica coffee in Benguet, Philippines

“…Several literatures have characterized the properties of defective coffee beans to improve the quality of commercial coffee. Published data on the characteristics of defective coffee were described using Fourier transform infrared spectroscopy (Craig et al, 2012), physical, organoleptic and chemical analysis (Franca et al, 2005a), and cup quality (Franca et al, 2005b) to distinguish them from non-defective coffee beans. However, these methods are not common to coffee farmers and screening for coffee defects is only done visually, relying primarily on morphological or sensory properties as basis for the classification of coffee beans.…”