Analysis of the extraction kinetic modelling for natural compounds is essential for industrial application. The second order rate model was applied to estimate the extraction kinetics of conventional solid-liquid extraction (CSLE), ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE) of total polyphenols (TPC) from saffron floral bio-residues at different solid-to-liquid ratios (RS/L)(1:10, 1:20, 1:30, 1:50 g ml-1), ethanol 59% as solvent and 66 °C temperature. The optimum solid-to-liquid ratios for TPC kinetics were 1:20 for CLSE, 1:30 for UAE and 1:50 for MAE. The kinetics of total anthocyanins (TA) and antioxidant activity (AA) were investigated for the optimum RS/L for each method. The results showed a good prediction of the model for extraction kinetics in all experiments (R2 > 0.99; NRMS 0.65-3.35%). The kinetic parameters were calculated and discussed. UAE, compared with the other methods, had the greater efficiency for TPC, TA and AA.
Keywords: Anthocyanins; Extraction; Kinetic model; Microwaves; Polyphenols; Saffron floral bio-residues; Solid-to-liquid ratio; Ultrasound.
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