Kinetic study of polyphenols extraction from olive (Olea europaea L.) leaves using instant controlled pressure drop texturing

• Polyphenols kinetic extraction from DIC-texturing olive leaves using UPLC.
• The application of DIC texturing is a relevant way to intensify polyphenols extraction of olive leaves.
• The use of DIC treatment shortened the extraction time from 120 min to 15 min.
• DIC texturing improves the diffusivity and the starting accessibility of olive leaves polyphenols.
• The CWD model has been a relevant methodology to describe the impact of DIC texturing.

The aim of this investigation is to study the impact of the technology of instant controlled pressure drop: “DIC” on the kinetics extraction of olive leaf (Olea europaea L.) polyphenols. The conditions of extraction were: ethanol 95%, temperature: 55 °C and ratio r = 40 g g−1 dry basis for 3 h. The extraction kinetics of total polyphenols content (TPC) of DIC-treated and untreated leaves were performed according to the method of Folin–Ciocalteau. The ultra-performance liquid chromatography (UPLC) was used to study the extraction kinetics of seven phenolic compounds of olive leaves: apigenin-7-glucoside, hydroxytyrosol, luteolin-7-glucoside, oleuropein, tyrosol, vanillic acid, and verbascoside. DIC-assisted solvent extraction allowed reducing the extraction time from 120 to 15 min while increasing the extracted yields. Phenomenological analysis of extraction kinetics was determined through the two-stage Coupled Washing/Diffusion CWD kinetic model. DIC texturing could, in favorable cases, increase the starting accessibility and systematically the internal effective diffusivity for phenolic compounds.