Extraction of purple sweet potato anthocyanins
Purple sweet potato powder were put into a 50ml conical
flask, then added in acid–ethanol (HCl, 1.5 mol/l) with
different solid–liquid ratio (1:15–1:30) and put in thermostatic
water bath at selected temperatures (40–80 1C) for
various duration periods of time (1:15–1:30), then,
centrifuged at 4000 rpm for 15 min. The supernatant was
collected and transferred into 50 ml volumetric flask for the
determination of anthocyanins yield. About 1 g of the
samples was used for each treatment.