Effect of pulsed electric fields and high voltage electrical discharges on polyphenol and protein extraction from sesame cake

• Extraction of phenolic compounds and proteins from sesame cake was performed.
• The effect of two different electrotechnologies was analyzed.
• Extraction yield improved when the technologies were applied as pre-treatments.
• Electrotechnologies reduce the need of ethanol and high temperatures for extraction.
• Mass effective diffusivity calculation confirmed the efficacy of the technologies.

The study evaluates the effect of pulsed electric fields (PEF) and high voltage electrical discharges (HVED) on the extraction of sesame cake compounds. Different energy inputs were applied and, afterwards, PEF and HVED were used as pre-treatments to diffusion. Diffusion kinetics were evaluated in diverse ethanol concentrations and temperatures. The extracts were analyzed for polyphenols, lignans and proteins. According to the results, the disintegration index and the polyphenol and protein contents increased with the energy inputs, until 83 kJ/kg was reached. During diffusion, both pre-treatments improved extraction yields of polyphenols and lignans through different solvents. For diffusion in different temperatures, PEF and HVED had a significant positive effect on the extraction of proteins and polyphenols when compared to the control sample. Results show that the use of PEF or HVED can reduce the use of organic solvents and the need for high temperatures to improve diffusion.Industrial relevanceThere is an increasing demand by the industry for the development of extraction procedures that reduce or eliminate the need for organic solvents and high temperatures. Also, food producers are aiming to find new application for by-products from the industry. PEF and HVED assisted extraction damages the product cells, increasing diffusion from the product to the solvent. The concentration of polyphenols and protein in the solvent after PEF and HVED treatments shows that the use of these techniques is relevant for an industrial use, since solvent amount and extraction time and temperature can be reduced.