Effect of DIC Technology on Phenolic Content and Antioxidant Activity of Rheum ribes L. rhizome Extracts

Rheum ribes L. (rhubarb) is one of the most important medicinal Mediterranean plants. Its rhizomes’ aqueous decoctions have become common among patients suffering from various ailments. Instant Controlled Pressure-Drop (DIC) is a high temperature-short time treatment (HTST) followed by an abrupt pressure-drop (ΔP/Δt>500 kPa.s-1) towards a vacuum (about 5 kPa). It increases the expansion and reduces the tortuosity to ensure better diffusivity and higher availability of the active molecules. In this work, we assessed the impact of DIC treatment of R. ribes rhizomes on the phytochemical content and antioxidant activity of their aqueous extract. Rheum ribes rhizomes were collected, dried, ground, and sieved to be then treated with DIC technology. DIC treatment significantly impacted the total phenolic (TPC) and flavonoid (TFC) contents and scavenging capacity at low saturated steam pressures. Indeed, the highest TPC and TFC values and the greatest antioxidant activity were recorded at 260 kPa. However, there was no significant influence of the DIC treatment time on TPC and TFC. Future work will focus on optimizing the DIC processing parameters for the highest yield of phytochemicals in the aqueous extracts of R. ribes rhizomes.