2.4. Analytical methods
Total pectinase activity (TPA) was determined by measuring the reduction of viscosity of citric pectin solution
(6.3 g/L), in an acetate buffer solution 0.05 mol/L, pH 4.0. The analysis was performed using 3.2 mL sample diluted in 14.8 mL of citric pectin, at 30 C for 30 min. Thereafter, viscosity variations were measured with a viscometer (BROOKFIELD ENGINEERING, model DV-IIþ, USA). One unit of TPA was defined as the amount of enzyme that reduces the viscosity to 50%, according to standard conditions (Couri & Farias, 1995).