Optimisation of olive oil extraction by means of enzyme processing aids using response surface methodology

The aim of the present work was to optimise the oil extraction process of the Italian olive fruits of Coratina cultivar using a previously selected enzyme formulation. To this Purpose, the combined effects of the malaxation time (t) and the concentration of the enzyme formulation (C-E,), added at the beginning of the malaxation step, were investigated by a 3(2) full factorial design combined with response Surface methodology, selecting the concentration of total polyphenols (TP) and o-diphenols (OD), the oil extraction yield (Y) and the antiradical power (ARP) as the response variables. The model enabled LIS to identify the optimum operating conditions (t = 91.64 min and C-E = 25.00mL/kg(paste)), under which it predicted TP = 844.30 mu g(CAE)/g(oil:); OD = 120.80 mu g(CAE)/g(oil); ARP = 24.93 mu g(DPPH)/mu L-extract and Y = 15.72g(oil)/100g(paste). These results, which were confirmed by additional tests performed within selected ranges of variables, suggest that the use of the the proposed enzyme treatment could enhance quantity and quality levels of the Product. (C) 2008 Elsevier B.V. All rights reserved.