Characterisation of polyphenols and antioxidant properties of five lettuce varieties and escarole

Rafael Llorach; Ascensión Martínez-Sánchez; Francisco A Tomás-Barberán; María I Gil; Federico Ferreres

doi:10.1016/j.foodchem.2007.11.032

Characterisation of polyphenols and antioxidant properties of five lettuce varieties and escarole

Food Chem. 2008 Jun 1;108(3):1028-38. doi: 10.1016/j.foodchem.2007.11.032. Epub 2007 Nov 23.

Authors

Rafael Llorach¹, Ascensión Martínez-Sánchez¹, Francisco A Tomás-Barberán¹, María I Gil¹, Federico Ferreres²

Affiliations

¹ Research Group on Quality, Safety and Bioactivity of Plant Foods, Food Science and Technology Department, CEBAS-CSIC, P.O. Box 164, Espinardo, Murcia E-30100, Spain.
² Research Group on Quality, Safety and Bioactivity of Plant Foods, Food Science and Technology Department, CEBAS-CSIC, P.O. Box 164, Espinardo, Murcia E-30100, Spain. Electronic address: federico@cebas.csic.es.

PMID: 26065768
DOI: 10.1016/j.foodchem.2007.11.032

Abstract

Salad vegetables could be relevant as dietary sources of natural antioxidants. A better knowledge of their composition can be useful for understanding their potential bioavailability and biological activities. The antioxidant compounds, polyphenols and vitamin C, have been determined in five varieties of lettuce (iceberg, romaine, continental, red oak leaf, lollo rosso) and one variety of escarole (frissé). The polyphenol study by HPLC-DAD-MS/MS ESI allowed the identification of two compounds previously not reported in lettuce; quercetin and luteolin rhamnosyl-hexosides. Qualitative and quantitative differences were observed between the polyphenol profiles. Caffeic acid derivatives were the main phenolics in green varieties, while flavonols were detected in higher quantities in red varieties and escarole, and anthocyanins were only present in red-leafed varieties. The highest total phenolic content was observed in red-leafed varieties while the highest level of vitamin C was detected in the continental variety. The red varieties showed the highest antioxidant activity by all the methods assayed.

Keywords: ABTS; Chemometric; DPPH; FRAP; Flavones; Hierarchical cluster analysis; Hydroxycinnamic acids; Lettuce varieties; Principal component analysis.