Abstract:Polyphenols were extracted from the needles of different pine species by high-shear mixing emulsification. Shear speed, shear time, ethanol concentration, sample to solvent ratio, and shear temperature were used as the indices. From the results of single factor testing, ethanol concentration, shear time, and extraction temperature were selected as the factors to be considered for the steepest ascent and response surface methodology using a central composite design. The optimum extraction conditions were as follows: shear speed: 18000 r/min, sample to solvent ratio: 1:10, ethanol concentration: 64%, shear time: 140 s, and shear temperature: 44 ℃. The yields of polyphenols from the needles of Pinus koraiensis, Abies nephrolepis, Pinus sylvestris, Pinus tabulaeformis, and Picea koraiensis were 19.7623, 24.6992, 14.0626, 9.4983, and 29.7984 mg/g, respectively. Meanwhile, 2,2-diphenyl-1-picrylhydrazyl (DPPH·) scavenging ability and total reducing power were used as indicators to compare the antioxidant capacities of the extracted polyphenols from the five pine species; these were in the order of Pinus koraiensis > Pinus tabulaeformis > Picea koraiensis > Pinus sylvestris > Abies nephrolepis. When 2,2′-azino-bis(3-ethylbenzothiazoline -6-sulfonic acid ABTS+· was used as the indicator, the antioxidant capacities were in the order of Pinus sylvestris > Pinus koraiensis > Pinus tabulaeformis > Picea koraiensis > Abies nephrolepis.
