Tomato processing waste devoid of seeds was obtained from Pezziol SPA, Parma, Italy. The average particle size and water content of the sample were ⩽0.5 mm and 35%, respectively. HPLC grade acetone, n-hexane, methanol and acetonitrile were purchased from Sigma–Aldrich, USA. Lycopene standard of HPLC grade (⩾95%) and solid sodium chloride (NaCl) (⩾99.5%) were obtained from Sigma–Aldrich, USA. Milli-Q ultrapure water with a resistivity of 18.3 MΩ cm was used in all the steps (Millipore, Germany).