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 (CE), added at the beginning of the malaxation step, were investigated by a 32 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 us to identify the optimum operating conditions (t = 91.64 min and CE = 25.00 mL/kgpaste), under which it predicted TP = 844.30 μgCAE/goil; OD = 120.80 μgCAE/goil; ARP = 24.93 μgDPPH/μLextract and Y = 15.72 goil/100 gpaste. These results, which were confirmed by additional tests performed within the selected ranges of variables, suggest that the use of the proposed enzyme treatment could enhance quantity and quality levels of the product.