par Mai, Huynh Cang ;Truong, Vinh;Debaste, Frédéric
Référence International Congress of Chemical an Process Engineering(21th: 23-27 Août 2014: Prague, République Tchèque), Proceedings of the CHISA-21
Publication Publié, 2014-08-24
Abstract de conférence
Résumé : Gac fruit oil is rich in carotenoids, mainly β-carotene and lycopene which are natural pigments, pro-vitamin A and have a high antioxidant activity. Carotenoids concentration using membrane separation is simpler than using an organic solvent, a hot or a cold concentration, because of its low energy consumption, low temperatures, high selectivity and absence of added chemical products.In this paper the concentration of gac fruit oil using a pilot scale (15L of feed per batch) ultrafiltration device is studied. To our knowledge, this has never been addressed in a published paper. The impact on membrane pore size, transmembrane pressure, temperature is systematically studied in term of impact on the permeate flux and its evolution over time. The different components of the membrane resistance (intrinsic, polarization and fouling) are evaluated. The retention of the total carotenoids, phospholipids and free fatty acid are systematically monitored. Key properties for further uses of the concentrated oil are also measured (solid content, lipophilic and hydrophilic antioxidant activity using DPPH assay and dynamic viscosity).The results show that the membrane can be efficiently approached using a Darcy law with only the viscosity of the oil that is dependent on temperature. The experiments allow identifying an optimal functioning with 5 nm pore size a transmembrane pressure of 2 bar and a temperature of 40°C. The major part of final total resistance due to polarization concentration resistance (55 %) while fouling resistance contributes for 30 %.These conditions are a trade-off between flux and retention that allow the production of a significant quantity of permeate with low carotenoids concentrations (the retention coefficient are of 88%, 5% and 1% for the carotenoids, phospholipids and 1% free fatty acid respectively). At the end of a 150 min experiment the total carotenoid content reaches 65g/l while the initial oil comprises 7.5g/l. The evolution of the antioxidant activity shows that the lypophilic activity scales linearly with the total carotenoid content while a part of the hydrophilic antioxidant activity is lost for the retentate.Further developments should address the crystallisation of the oil in order to retrieve purified carotenoids crystals.