Front-face fluorescence excitation-emission matrices in combination with three-way chemometrics for the discrimination and prediction of phenolic response to vineyard agronomic practices

Manuel Cabrera-Bañegil; Esperanza Valdés-Sánchez; Daniel Moreno; Diego Airado-Rodríguez; Isabel Durán-Merás

doi:10.1016/j.foodchem.2018.07.071

Front-face fluorescence excitation-emission matrices in combination with three-way chemometrics for the discrimination and prediction of phenolic response to vineyard agronomic practices

Food Chem. 2019 Jan 1:270:162-172. doi: 10.1016/j.foodchem.2018.07.071. Epub 2018 Jul 18.

Authors

Manuel Cabrera-Bañegil¹, Esperanza Valdés-Sánchez², Daniel Moreno², Diego Airado-Rodríguez³, Isabel Durán-Merás⁴

Affiliations

¹ Department of Analytical Chemistry, Faculty of Sciences, University of Extremadura, 06006 Badajoz, Spain. Electronic address: manuelcb@unex.es.
² Technological Institute of Food and Agriculture (CICYTEX-INTAEX), Junta of Extremadura, 06007 Badajoz, Spain.
³ Department of Sciences and Mathematics Education, Education School, University of Extremadura, 06006 Badajoz, Spain.
⁴ Technological Institute of Food and Agriculture (CICYTEX-INTAEX), Junta of Extremadura, 06007 Badajoz, Spain; Research Institute on Water, Climate Change and Sustainability (IACYS), University of Extremadura, 06006 Badajoz, Spain.

PMID: 30174030
DOI: 10.1016/j.foodchem.2018.07.071

Abstract

Phenolic extracts from cv Tempranillo grapes subjected to water stress and irrigation treatment, both of them with high and low crop load, were analyzed by front-face fluorescence. Excitation-emission matrices (EEMs) were analyzed by means of unsupervised parallel factor analysis (PARAFAC), PARAFAC supervised by linear discriminant analysis, and discriminant unfolded partial least-squares. All algorithms allowed to differentiate between water stress and irrigation grape samples when the fluorescence maxima region of catechin and epicatechin, and resveratrol was considered. A central composite design was employed for the calibration of catechin, epicatechin and resveratrol. Resveratrol was quantified by U-PLS in both, irrigated and water stressed samples, and levels between 3.46 ± 0.22 and 4.67 ± 0.08 μg mL^-1 and 2.43 ± 0.60 and 3.03 ± 0.10 μg mL^-1, respectively, were found. PARAFAC only allowed the determination of the sum of catechin plus epicatechin (R² = 0.9397). The determination of total catechin plus epicatechin by means of PARAFAC was successfully validated by liquid chromatography.

Keywords: Catechin; Epicatechin; Front-face fluorescence; LDA; PARAFAC; Resveratrol.

MeSH terms

Calibration
Catechin / analysis
Factor Analysis, Statistical
Farms
Least-Squares Analysis
Phenols / analysis*
Spectrometry, Fluorescence / methods*
Vitis / chemistry*
Wine / analysis*

Substances

Phenols
Catechin