ATPE used as a primary separation method has been widely
applied for the recovery of biological products due to its easiness for
scale-up, high capacity and yield, low cost and short processing time
[9-12]. Furthermore, ATPE has the potential to achieve the desired
purification and concentration of the product in a single step. In the
separation of the pigments, polyethylene glycol (PEG)/ (NH4)2SO4
system has been used to separate betalains from crude beetroot extract
[13], and Mageste et al. studied ATPE of natural dye carmine with
polyethylene oxide (PEO)/Li2SO4 system [14]. However, polymers are
very expensive and not easy to recover. Recently, a novel aqueous twophase system (ATPS) composed of short chain alcohol and salt has
been used to extract natural compounds due to its low cost and easy
recovery of solvent by evaporation. For example, ethanol/ (NH4
)2
SO4
system has been used to separate piceid, resveratrol and emodin from
Polygonum cuspidatum [15], and n-propanol/ phosphate system has
been used for the purification of salvianolic B from crude extract of
Salvia miltiorrhiza by counter-current chromatography (CCC) [16].
Encouraged by the previous results, ATPE is thought to be suitable for
the extraction of natural pigments.