Ultrasound assisted extraction of trans-resveratrol from red grapes; a taguchi optimization approach

Resveratrol is a polyphenolic compound belongs to the stilbene family which has two phenolic rings (Fig.1). It is a natural compound found in red grapes, peanuts, pistachios, fruits such as blackberries or raspberries, plants like Yucca, fescues, hellebore, trees such as eucalyptus and fir and in chocolate. The biologically active form of resveratrol is its trans isomer [1].Resveratrol has many therapeutic properties (anticancer, antiviral, anti-inflammatory, neuroprotective and etc. It was associated with the ‘‘French Paradox’’ which refers to the observation that in south-west France, despite a high consumption of animal fats, the incidence of cardiovascular disease is relatively low, due to the consumption of resveratrol rich drinks. Ultrasound is a key-technology in achieving the objective of sustainable ‘‘green” chemistry and extraction. Ultrasound is well known to have a significant effect on the rate of various processes in the chemical and food industry. Using ultrasound, full extractions can now be completed in minutes with high reproducibility, reducing the consumption of solvent, simplifying manipulation and work-up, giving higher purity of the final product, eliminating.post-treatment of waste water and consuming only a fraction of the fossil energy normally needed for a conventional extraction method such as Soxhlet extraction, maceration or Clevenger distillation [2]. In this study a taguchi optimization method was applied for ultrasound assisted extraction of trans-resveratrol from dried red grape skins evaluated by high performance liquid chromatography.