Phenolic profile and hydrophilic antioxidant capacity as chemotaxonomic markers of tomato varieties

Tomatoes (Solanum lycopersicum L.), the second most important vegetable crop worldwide, are a key component in the so-called "Mediterranean diet", which is strongly associated with a reduced risk of chronic degenerative diseases. In this work, we evaluate the differences in the total and individual polyphenol content and hydrophilic antioxidant capacity of seven varieties of tomato cultivated in Vegas Bajas del Guadiana, Badajoz (Spain), which were collected from two consecutive harvests (2008-2009). Hydrophilic antioxidant capacity was evaluated using the TEAC assay, while the Folin-Ciocalteau assay with a previous cleanup was used to establish total polyphenol content. The method was optimized and validated. Individual polyphenols were quantified using liquid chromatography/electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) on a triple quadrupole. All compounds were found to be significantly different when analysis of variance was performed. Results from the principal component analysis show that phenolic compounds and hydrophilic antioxidant capacity were responsible for the differences among tomato samples according to variety.