Purification of Grape Proanthocyanidins by Membrane Ultrafiltration
Katherina Fernández E., Rocío Paiva, and Estrella Aspé
Department of Chemical Engineering, University of Concepción, Concepción, Chile
Abstract—The objective of this study was to maximize the permeate flux (J) in the purification by UF of a grape seed extract, by evaluating the effect of operating variables: transmembrane pressure and tangential velocity on J and on the extracts chemical characteristics. Concentrations of total phenols, mean degree of polymerization (mDP), and average molecular weights (aMW) were compared. Flat membranes of polyvinylidene fluoride (PVDF) with a molecular weight cut off (MWCO) of 10 (kDa) and 1 (kDa) were used in an Alfa Laval equipment LAbUnit M10. The pressure was tested at 2, 3, 4 and 5 (bar) at a constant speed of 0.9 (m/s) and the tangential velocity was evaluated at 1.2, 1.3 and 1.4 (m/s) at 5 bar pressure and constant temperature (20ºC). The transmembrane pressure and tangential velocity tests confirmed a direct relationship of these variables with J for both membranes. The J for 1kDa membrane was more sensitive to changes in pressure, with a maximum J of 15.18 (L/m2h), while that for 10 kDa membrane J reached a maximum value of 37.50 (L/m2h), both at 20 °C, 5 bar and 1.3 (m/s). The purification by UF reduced the mDP of the extracts from 7.15 up to 1-3 units of flavan-3-ols, corresponding to dimmers and trimmers in the permeate. To maximize J, the phenolics concentration, and minimize the mDP, carrying out the UF process with 10kDa membrane to 5 bar and 1.3 m/s would be optimal.
Index Terms—ultrafiltration, grape seed, phenolic compounds, purificaction, flavan-3-ols, permeate flux
Cite: Katherina Fernández E., Rocío Paiva, and Estrella Aspé, "Purification of Grape Proanthocyanidins by Membrane Ultrafiltration," Journal of Medical and Bioengineering, Vol. 4, No. 3, pp. 178-183, June 2015. Doi: 10.12720/jomb.4.3.178-183
Index Terms—ultrafiltration, grape seed, phenolic compounds, purificaction, flavan-3-ols, permeate flux
Cite: Katherina Fernández E., Rocío Paiva, and Estrella Aspé, "Purification of Grape Proanthocyanidins by Membrane Ultrafiltration," Journal of Medical and Bioengineering, Vol. 4, No. 3, pp. 178-183, June 2015. Doi: 10.12720/jomb.4.3.178-183
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