[Selective removal of tannins from Polygonum cuspidatum extracts using collagen fiber adsorbent].
OBJECTIVE
To investigate the selective removal of tannins from Polygonum cuspidatum extracts by using collagen fiber adsorbent, and to evaluate the adsorption and desorption performances of collagen fiber adsorbent to tannins.


METHODS
The adsorbent was prepared from bovine skin collagen fiber through crosslinking reaction of glutaraldehyde, and then used for the selective removal of tannins from P. cuspidatum extracts. Gelatin-turbidity method, gelatin-ultraviolet spectrometry method and HPLC were used for detection of tannins in the solutions. Ethanol-water solutions with varying concentration were used to test their desorption ability of tannins in order to choose proper desorption solution. On the basis of batch experimental results, the column adsorption and desorption tests were carried out, by using gelatin-turbidity method for detection of tannins.


RESULTS
The collagen fiber adsorbent exhibited excellent adsorption selectivity to tannins. It was found that tannins of P. cuspidatum were completely removed, while nearly no adsorption of active components (resveratrol as representative) was found. Moreover, the collagen fiber adsorbent could be regenerated by using 30% ethanol-water solution and then reused.


CONCLUSIONS
The collagen fiber adsorbent can be considered as a promising material for selective removal of tannins from P. cuspidatum extracts.
Li
Juan
J
National Engineering Laboratory for Clean Technology of Leather Manufacture, Sichuan University, Chengdu 610065, China. blackgound@163.com
Liao
Xuepin
X
Shu
Xingxu
X
Shi
Bi
B
D000327:Adsorption; D003094:Collagen / Q000737:chemistry*; D045468:Fallopia japonica / Q000737:chemistry*; D010936:Plant Extracts / Q000032:analysis*; D013634:Tannins / Q000302:isolation & purification*
D010936:Plant Extracts; D013634:Tannins; D003094:Collagen