Study on tannins extraction process from Chestnut shell and scavenging effects of DPPH free radical

The aim of the study was to obtain the optimum extraction method of tannins and study its scavenging effects of DPPH free radical from chestnut shell,which is a kind of waste in chestnut production.It was determined that the optimum extraction method was refluxing method and the optimum extraction solvent was ethanol by screening experiments. On the basis,single factor experiments and orthogonal experiments were carried out. The effects of different volume fractions of ethanol,extraction time and solid- liquid ratio were explored. And the optimum extraction conditions were that 25% aqueous ethanol solution as the best extraction solvent,the solid /liquid ratio of 1 to 10.5 and extraction time 2 h. Under these conditions,the extraction ratio for the chestnut shell tannin reached 14.617 mg / g.The antioxidant activity of tannin crude extracts was investigated by DPPH method,and the results showed that tannin crude extracts from chestnut shell had strong antioxidant effect and it could be explored as a kind of natural antioxidants.