Efficient separation and purification of anthocyanins from saskatoon berry by using low transition temperature mixtures

Abstract

Different kinds of low transition temperature mixtures (LTTMs) were synthesized with DL-lactic acid and five different quaternary ammonium salts respectively, and their viscosity and solubility parameters change with different molar ratios of quaternary ammonium salt to DL-lactic acid were investigated and compared with anthocyanins. Then the LTTMs synthesized were used to extract anthocyanins from saskatoon berry (Amelanchier alnifolia Nutt.). It turned out that the choline chloride/DL-lactic acid (ChCl/LA) showed the best solubility of anthocyanins compared with the other LTTMs, which was in line with solubility parameter theory. Under the optimized process condition with 1 : 15 of molar ratio, 1 : 20 of solid to liquid ratio, 50 °C of extraction temperature and 45 min of extraction time, the extraction amount of anthocyanins reached 525.27 ± 0.82 mg per 100 g and the extracted rate of anthocyanins was 87.4%. Then the macroporous resin AB-8 adsorbent was used to separate and purify the anthocyanin compounds from saskatoon berry, with a recovery yield of 65.7%. Further, the confirmation of the purified anthocyanins was carried out using nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FT-IR) and high performance liquid chromatography-mass spectrometry (HPLC-MS). Finally, the purified anthocyanins were proved to be good antioxidants through the comparison with vitamin C and butylated hydroxytoluene.