Abstract: The objective of this research was to purify α-linolenic acid from Phyllanthus emblica L. seed oil by using silver iron complexation in order to obtain high purity and yield of α-linolenic acid. Firstly, the effects of silver nitrate concentration, volume fraction of methanol, complexation time and complexation temperature on the purity and yield of α-linolenic acid were investigated by one-factor-at-a-time method. Afterwards, three independent variables were selected out of the four process parameters for the optimization experiments which were done using Box-Behnken design with the purity and yield of α-linolenic acid as response variables. The results indicated that the optimal process parameters were obtained as follows: complexation temperature, 0 ℃; silver nitrate concentration, 2.29 mol/L; methanol volume fraction, 38.00%; and complexation time, 1.93 h, under which the purity and yield of α-linolenic acid were 93.30% and 73.37%, respectively. The remaining silver nitrate was recovered for a second complexation. The recovery of silver nitrate was 93.83% and the recovered Ag+ still had good complexation effect. Particularly, exogenous Ag+ was not introduced in the whole complexation process. Therefore, this method allowed successful separation and purification of α-linolenic acid from P. emblica L. seed oil while reducing the operating cost. Meanwhile, the method of silver iron complexation was safe and helpful for industrial application of P. emblica L. seed oil.

Key words: Phyllanthus emblica L. seed oil, α-linolenic acid, silver iron complexation