Phenolic compounds, lycopene and antioxidant activity in commercial varieties of tomato (Lycopersicum esculentum)

Nine commercial varieties of tomato (Rambo, Senior, Ramillete, Liso, Pera, Canario, Durina, Daniella and Remate) produced in Spain were analysed for their lycopene content, content of phenolic compounds and antioxidant capacity. The phenolic compounds were characterised as flavonoids (quercetin, kaempferol and naringenin) and hydroxycinnamic acids (caffeic, chlorogenic, ferulic and p-coumaric acids). Antioxidant activity was measured using the DPPH and ABTS assays. The concentrations of lycopene and the various phenolic compounds as well as the antioxidant activity were significantly influenced by the tomato variety. Quercetin, the most abundant flavonoid, was found in concentrations ranging between 7.19 and 43.59 mg kg(-1) fresh weight, while naringenin levels were lower than 12.55 mg kg(-1). The most abundant hydroxycinnamic acid was chlorogenic acid, with values ranging from 14 to 32 mg kg(-1) fresh weight, followed by caffeic acid, while p-coumaric and ferulic acids showed similar concentrations lower than 5 mg kg(-1). The highest content of lycopene was found in Ramillete, Pera and Durina (>50 mg kg(-1) fresh weight), while the concentration in the other varieties was between 50 and 30 mg kg(-1), with the exception of Liso (less than 20 mg kg(-1)). The antioxidant activity of tomato extracts varied with the tomato variety and the assay method used. Individual compounds found to be significantly related to antioxidant capacity were lycopene and ferulic and caffeic acids, but not quercetin and chlorogenic acid. (C) 2002 Society of Chemical Industry.