Intensification of Phenolic and Protein Extraction from

Intensification of Phenolic and Protein Extraction from Vine Shoots Hiba N. Rajha1,2, Nadia Boussetta1, Nicolas Louka2, Richard G. Maroun2, Eugene Vorobiev1 1) UTC/ESCOM, EA 4297 TIMR, Département de Génie des Procédés Industriels, Laboratoire Transformations Intégrées de la Matière Renouvelable, Université de Technologie de Compiègne, Centre de Recherche de Royallieu, Compiègne, France. 2) Centre d’Analyses et de Recherche, UR TVA, Faculté des Sciences, Université Saint-Joseph de Beyrouth, Lebanon

This study targeted the intensification of polyphenols and proteins extraction from vine shoots. After determining the optimal solid liquid extraction parameters, vine shoots were subjected to four different pre-treatments followed by the diffusion in the previously optimized conditions (water, pH 13). Pulsed electric fields (PEF) (13 kV/cm), high-voltage electrical discharges (HVED) (40 kV) and ultrasound-assisted extraction’s (USAE) (400W) phenolic and proteines yields were compared to the maximal values obtained by grinding. Polyphenols and proteins extractions were both significantly ameliorated with HVED, PEF and USAE as compared to the standard solid liquid diffusion. Energetic thresholds were defined for HVED (25.4 KJ/Kg), PEF (51 KJ/Kg) and USAE (3428 KJ/Kg), above which the enhancement of polyphenols and proteins extraction becomes significant. This suggested that HVED had the highest biomolecular extraction efficiency with the lowest energetic requirement as compared to PEF and USAE. Having various mechanisms of action and dissimilar impacts on the product fragmentation, each technique enables the obtainment of different phenolic (HVED (35 mg GAE/g DM), PEF (22 mg GAE/g DM), USAE (16 mg GAE/g DM)), and proteomic yields (HVED (4.5 mg GAE/g DM), PEF (3.2 mg GAE/g DM), USAE (3.2 mg GAE/g DM)), with different energetic thresholds. In accordance with the results the calculation of diffusion coefficients (m2/s) for both polyphenols and proteins showed better extraction enhancement for HVED, followed by PEF then USAE. However, proteins diffusion was faster than that of polyphenols, probably suggesting better accessibility to those molecules and/or their engagement in weaker noncovalent bonds, facilitating thus their release. The electrical conductivity disintegration index, Z, showed increasing cellular damage with the increased energy of the treatments for HVED, PEF and USAE. However, the effect of HVED was the highest in terms of tissue damage, which was manifested by the highest Z amongst the treatments for all the studied energies.