Optimization of the subcritical water extraction of phenolic antioxidants from Crocus sativus petals of saffron industry residues: Box-Behnken design and principal component analysis

摘要

Subcritical water extraction was investigated as a green technology for the extraction of phenolic compounds from Crocus sativus petals. A Box-Behnken design was utilized to determine the optimal extraction conditions. Extraction temperature (120-160 degrees C), extraction time (20-60 min) and water to solid (W/S) ratio (20-40 mL/g) were considered as the variables for the extraction of phenolic compounds. A second order polynomial model was fitted to each response and the regression coefficients were determined using least square methodology. There was a good correspondence between the experimental data and their predicted counterparts. The optimum conditions of extraction were estimated to be W/S ratio of 36 mL/g, temperature of 159 degrees C and time of 54 min. Extraction using these optimized conditions achieved the best TPC (1616 mg/100 g), TFC (239 mg/100 g), %DPPHSC (86.05%) and FRAP value (5.1 mM). Principal components analysis (PCA) allowed a better understanding of interactions between properties of extracted phenolic antioxidants.