Pinela, JoséPrieto Lage, Miguel A.Barreiro, M.F.Carvalho, Ana MariaOliveira, BeatrizVázquez, J.A.Ferreira, Isabel C.F.R.2016-10-032016-10-032016Pinela, José; Prieto, M.A.; Barreiro, M.F.; Carvalho, Ana Maria;Oliveira, M.B.P.P.; Vázquez, J.A.; Ferreira, Isabel C.F.R. (2016). Optimization of microwave-assisted extraction of hydrophilic and lipophilic antioxidants from a surplus tomato crop by response surface methodology. Food and Bioproducts Processing. ISSN 0960-3085. 98, p. 283–2980960-3085http://hdl.handle.net/10198/13352Tomato is the second most important vegetable crop worldwide and a rich source of industrially interesting antioxidants. Hence, the microwave-assisted extraction of hydrophilic (H) and lipophilic (L) antioxidants from a surplus tomato crop was optimized using response surface methodology. The relevant independent variables were temperature (T), extraction time (t), ethanol concentration (Et) and solid/liquid ratio (S/L). The concentration-time response methods of crocin and β-carotene bleaching were applied, since they are suitable in vitro assays to evaluate the antioxidant activity of H and L matrices, respectively. The optimum operating conditions that maximized the extraction were as follows: t, 2.25 min; T, 149.2 ºC; Et, 99.1 %; and S/L, 45.0 g/L for H antioxidants; and t, 15.4 min; T, 60.0 ºC; Et, 33.0 %; and S/L, 15.0 g/L for L antioxidants. This industrial approach indicated that surplus tomatoes possess a high content of antioxidants, offering an alternative source for obtaining natural value-added compounds. Additionally, by testing the relationship between the polarity of the extraction solvent and the antioxidant activity of the extracts in H and L media (polarity-activity relationship), useful information for the study of complex natural extracts containing components with variable degrees of polarity was obtained.engLycopersicon esculentumMicrowave-assisted extractionbeta-Carotene/crocin bleaching assayConcentration-time response modellingCentral composite designResponse surface methodologyjournal article10.1016/j.fbp.2016.02.002