Chlorogenic acids (CGA) represent a family of esters formed between quinic acid and one to four residues of certain trans- cinnamic acids, most commonly caffeic, p-coumaric and ferulic
[27]. In the mid-infrared region, a band from 675 to 900 cm À 1 (out-of-plane C–H bending vibration) is a potential indicator of chlorogenic acids and trigoneline [18]. In this study, from 800 to 835 cm À 1, positive coefficients for dark sour and black coffees and negative coefficients for light sour and immature were observed. Light sour and non-defective coffees exhibited negative coeffi- cients at 1334–1365 cm À 1, where in-plane O–H bending in phe- nolic compounds absorb [18]. An evaluation of Fig. 3a and b also show negative coefficients for non-defective coffee at 1674 cm À 1 that could be related to the C¼O stretching vibration in aryl conjugated acids [28].
In the NIR spectra, a number of regions were assi
Chlorogenic acids (CGA) represent a family of esters formed between quinic acid and one to four residues of certain trans- cinnamic acids, most commonly caffeic, p-coumaric and ferulic[27]. In the mid-infrared region, a band from 675 to 900 cm À 1 (out-of-plane C–H bending vibration) is a potential indicator of chlorogenic acids and trigoneline [18]. In this study, from 800 to 835 cm À 1, positive coefficients for dark sour and black coffees and negative coefficients for light sour and immature were observed. Light sour and non-defective coffees exhibited negative coeffi- cients at 1334–1365 cm À 1, where in-plane O–H bending in phe- nolic compounds absorb [18]. An evaluation of Fig. 3a and b also show negative coefficients for non-defective coffee at 1674 cm À 1 that could be related to the C¼O stretching vibration in aryl conjugated acids [28].In the NIR spectra, a number of regions were assi
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