Different Extraction Techniques on the Characteristic Properties of Valonea Tannin

Valonea extract is a natural tannage widely applied in leather industry which is produced via conventional hot water extraction method. On the otherhand more environmental friendly methods have started to be used in extraction technology recently. Present paper reports on the effect of different extraction methods on the properties of valonea extracts. For this purpose, conventional solvent extraction (CSE) (methanol/water mixture), supercritical CO 2 (scCO 2 ) extraction and pressurized fluid extraction (PFE) (water/CO 2 binary system) techniques have been employed on valonea and the obtained extracts have been characterized. Molecular weight of the tannins was determined by gel permeation chromatography (GPC), particle size was examined by Malvern Zetasizer instrument, chemical structure by Fourier Transform Infrared Spectroscopy (FTIR). Tannin content was also examined and the results were compared with commercial valonea extract (CVT). The results showed that especially particle size of the tannins was affected by the applied extraction method and the smallest particle size was obtained by PFE method as 505.3 nm compared to commercial tannin as 983.0 nm of average particle size. PFE method was also provided more uniform extract according to the polydispersity index values. GPC and FTIR analyses showed slightly differences on the characteristics of tannins.