Optimization of experimental parameters in subcritical water extraction of bioactive constituents from the saffron (Crocus sativus L.) corm based on response surface methodology

Abstract

Subcritical water extraction (SWE) was employed for the extraction of bioactive constituents from Crocus sativus corms. The extraction temperature and time, as the principal experimental variables, were investigated in the range of 100–180 °C and 10–30 min respectively. A central composite face-centered design (CCD) showed 180 °C and 21.99 min were the optimum conditions for maximizing the antioxidant activity and total phenolic content (TPC) of the extract. Under the optimized conditions, the amount of TPC, ferric reducing antioxidant power (FRAP) and the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) IC50 were 816.34 mg gallic acid/100 g dry matter, 1138.95 mM, and 61.67 mg kg−1, respectively. Gas chromatography–mass spectrometry (GC–MS) analysis showed dodecane (20.043%) is one of the main non-polar constituents in the saffron corm (SC) SWE extract (SC-SWE extract). Microdilution and disc diffusion methods revealed a degree of activity against Staphylococcus aureus and Escherichia coli. The results exhibited that SWE is a practical technique to extract bioactive constituents with antioxidant and antibacterial properties from Crocus sativus corms.