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High Voltage Electrical Discharges, Pulsed Electric Field, and Ultrasound Assisted Extraction of Protein and Phenolic Compounds from Olive Kernel


The study was aimed at improvement of recovery of intracellular valuable compounds from olive kernels (Olea europaea). High voltage electrical discharges (HVED), pulsed electric field (PEF), and ultrasound (US) were applied as pretreatments before extraction. The influence of HVED energy input (0–109 kJ/kg), pH (2.5–12), and ethanol (0–50 %) on the efficiency of the extraction was studied. The extracts obtained immediately after pretreatments were analyzed for total phenolic compounds, antioxidant activity, proteins, and pigments. HVED treatment was demonstrated to be more effective than ultrasound and pulsed electric field in terms of energy input and effective treatment time to extract phenolic compounds and proteins. Moreover, the application of HVED increased significantly the aqueous and hydro-ethanolic extractions of total phenolic content (TPC), and proteins of the recovered extracts when energy input was augmented. pH and ethanol percentage had also a significant influence in TPC, protein, and antioxidant recovery. The interesting observation is that pH 2.5 resulted in the optimum conditions to recover TPC and antioxidant capacity. However, the higher protein content was found when pH 12 was used. Multiple response optimization showed that TPC, content of proteins, and antioxidant capacity (Trolox equivalent antioxidant capacity (TEAC) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) values) of the sample were further maximized after HVED pretreatment at energy input 66 kJ/kg at pH 2.5 followed by extraction in 49 % ethanol. TPC, content of proteins, TEAC, and DPPH values under such conditions of extraction were 626.6 mg GAE/L, 0.225 mg/mL, 9.80 mM TE, and 7.61 mM TE, respectively.

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  1. Barba, F. J., Esteve, M. J., Tedeschi, P., Brandolini, V., & Frígola, A. (2013). A comparative study of the analysis of antioxidant activities of liquid foods employing spectrophotometric, fluorometric, and chemiluminescent methods. Food Analytical Methods, 6(1), 317–327.

    Article  Google Scholar 

  2. Boussetta, N., & Vorobiev, E. (2014). Extraction of valuable biocompounds assisted by high voltage electrical discharges: a review. Comptes Rendus Chimie, 17(3), 197–203.

    Article  CAS  Google Scholar 

  3. Boussetta, N., Lebovka, N., Vorobiev, E., Adenier, H., Bedel-Cloutour, C., & Lanoisellé, J.-L. (2009). Electrically assisted extraction of soluble matter from chardonnay grape skins for polyphenol recovery. Journal of Agricultural and Food Chemistry, 57(4), 1491–1497.

    Article  CAS  Google Scholar 

  4. Boussetta, N., Turk, M., De Taeye, C., Larondelle, Y., Lanoiselle, J. L., & Vorobiev, E. (2013). Effect of high voltage electrical discharges, heating and ethanol concentration on the extraction of total polyphenols and lignans from flaxseed cake. Industrial Crops and Products, 49, 690–696.

    Article  CAS  Google Scholar 

  5. Bradford, M. M. (1976). A refined and sensitive method for the quantitation of microgram quantities of protein using the principle of protein-dye binding. Analytical Biochemistry, 72, 248–255.

    Article  CAS  Google Scholar 

  6. Carbonell-Capella, J. M., Barba, F. J., Esteve, M. J., & Frígola, A. (2013). High pressure processing of fruit juice mixture sweetened with Stevia rebaudiana Bertoni: optimal retention of physical and nutritional quality. Innovative Food Science and Emerging Technologies, 18, 48–56.

    Article  CAS  Google Scholar 

  7. Chemat, F., Zill-E-Huma, & Khan, M. K. (2011). Applications of ultrasound in food technology: processing, preservation and extraction. Ultrasonics Sonochemistry, 18(4), 813–835.

    Article  CAS  Google Scholar 

  8. Galanakis, C. M. (2012). Recovery of high added-value components from food wastes: conventional, emerging technologies and commercialized applications. Trends in Food Science & Technology, 26(2), 68–87.

    Article  CAS  Google Scholar 

  9. Galanakis, C. M. (2013). Emerging technologies for the production of nutraceuticals from agricultural by-products: a viewpoint of opportunities and challenges. Food and Bioproducts Processing, 91(4), 575–579.

    Article  CAS  Google Scholar 

  10. Galanakis, C. M., Tornberg, E., & Gekas, V. (2010a). A study of the recovery of the dietary fibres from olive mill wastewater and the gelling ability of the soluble fibre fraction. LWT - Food Science and Technology, 43(7), 1009–1017.

    Article  CAS  Google Scholar 

  11. Galanakis, C. M., Tornberg, E., & Gekas, V. (2010b). Dietary fiber suspensions from olive mill wastewater as potential fat replacements in meatballs. LWT - Food Science and Technology, 43(7), 1018–1025.

    Article  CAS  Google Scholar 

  12. Ghanbari, R., Anwar, F., Alkharfy, K. M., Gilani, A.-H., & Saari, N. (2012). Valuable nutrients and functional bioactives in different parts of olive (Olea europaea L.)—a review. International Journal of Molecular Sciences, 13(3), 1291–1340.

    Google Scholar 

  13. Keceli, T., & Gordon, M. H. (2001). The antioxidant activity and stability of the phenolic fraction of green olives and extra virgin olive oil. Journal of the Science of Food and Agriculture, 81(14), 1391–1396.

    Article  CAS  Google Scholar 

  14. Lichtenthaler, H. K. (1987). Chlorophylls and carotenoids: pigments of photosynthetic biomembranes. Methods in Enzymology, 148(C), 350–382.

    Article  CAS  Google Scholar 

  15. Liu D., Vorobiev D., Savoire R., & Lanoiselle, J.-. L. (2011). Extraction of polyphenols from grape seeds by unconventional methods and extract concentration through polymeric membrane. In Food Process Engineering in a Changing World. Proceedings of the 11th International Congress on Engineering and Food (pp. 1939–1940).

  16. Max, B., Salgado, J. M., Cortes, S., & Dominguez, J. M. (2010). Extraction of phenolic acids by alkaline hydrolysis from the solid residue obtained after prehydrolysis of trimming vine shoots. Journal of Agricultural and Food Chemistry, 58(3), 1909–1917.

    Article  CAS  Google Scholar 

  17. Meireles, M. A. A. (2009). Extracting bioactive compounds for food products theory and applications. Boca Raton: CRC Press.

    Google Scholar 

  18. Nefzaoui, A., Hellings, P., & Vanbelle, M. (1983). Ensiling olive pulp with ammonia: effects on voluntary intake and digestibility measured by sheep. In 34th Annual Meeting of the EAAP Annual Commission. Madrid.

  19. Niaounakis, M., & Halvadakis, C. P. (2004). Olive-Mill waste management. Literature Review and Patent Survey. (G. Dardanos, Ed.). Typothito. Athens.

  20. Rajha, H. N., Boussetta, N., Louka, N., Maroun, R. G., & Vorobiev, E. (2014). A comparative study of physical pretreatments for the extraction of polyphenols and proteins from vine shoots. Food Research International. doi:10.1016/j.foodres.2014.04.024.

    Google Scholar 

  21. Rawel, H. M., Meidtner, K., & Kroll, J. (2005). Binding of selected phenolic compounds to proteins. Journal of Agricultural and Food Chemistry, 53(10), 4228–4235.

    Article  CAS  Google Scholar 

  22. Re, R., Pellegrini, N., Proteggente, A., Pannala, A., Yang, M., & Rice-Evans, C. (1999). Antioxidant activity applying an improved ABTS radical cation decolorization assay. Free Radical Biology and Medicine, 26(9–10), 1231–1237.

    Article  CAS  Google Scholar 

  23. Samaniego Sanchez, C., Troncoso Gonzalez, A. M., Garcia-Parrilla, M. C., Quesada Granados, J. J., de la Serrana, H., & Lopez Martinez, M. C. (2007). Different radical scavenging tests in virgin olive oil and their relation to the total phenol content. Analytica Chimica Acta, 593(1), 103–107.

    Article  CAS  Google Scholar 

  24. Singleton, V. L., Orthofer, R., & Lamuela-Raventos, R. M. (1999). Analysis of total phenols and other oxidation substrates and antioxidants by means of Folin-Ciocalteu reagent. In L. Packer (Ed.), Oxidants and antioxidants. Part A (Vol. 299, pp. 152–178). Academic Press, New York.

  25. Sun, R. C., & Tomkinson, J. (2002). Characterization of hemicelluloses obtained by classical and ultrasonically assisted extractions from wheat straw. Carbohydrate Polymers, 50(3), 263–271.

    Article  CAS  Google Scholar 

  26. Vorobiev, E., & Lebovka, N. (2010). Enhanced extraction from solid foods and biosuspensions by pulsed electrical energy. Food Engineering Reviews, 2(2), 95–108.

    Article  CAS  Google Scholar 

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F. J. Barba thanks the Valencian Autonomous Government (Consellería d’Educació, Cultura i Esport. Generalitat Valenciana) for the postdoctoral fellowship of the VALi+d program “Programa VALi+d per a investigadors en fase postdoctoral 2013” (APOSTD/2013/092).

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Correspondence to Nabil Grimi.

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Roselló-Soto, E., Barba, F.J., Parniakov, O. et al. High Voltage Electrical Discharges, Pulsed Electric Field, and Ultrasound Assisted Extraction of Protein and Phenolic Compounds from Olive Kernel. Food Bioprocess Technol 8, 885–894 (2015).

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  • Olive kernel
  • Extraction
  • High voltage electrical discharges
  • Pulsed electric fields
  • Ultrasound